阅读说明：本技术 发光材料性质预测方法、系统、电子设备和存储介质 (Method, system, electronic device, and storage medium for predicting property of luminescent material ) 是由 王悦 胡晗 毕海 李志强 于 2021-09-03 设计创作，主要内容包括：本发明涉及数据处理技术领域,尤其涉及一种发光材料性质预测方法、系统、电子设备和存储介质,发光材料性质预测方法包括：对无标签的发光材料分子数据进行节点层面的预训练,训练结果作为第一编码器；第一编码器对无标签的发光材料分子数据进行编码,标签从无的发光材料分子数据中抽取出发光材料分子中预定义的官能团,对所述官能团进行分组并组成序列,将序列作为自监督学习的标签进行训练,训练结果作为第二编码器；使用所述第二编码器对待预测的发光材料分子数据进行编码,对待预测的发光材料的性质进行预测。本发明通过设计节点层面和图层面的建模方法,让分子结构更好地被表征,解决了现有方法中出现的特征丢失问题。(The invention relates to the technical field of data processing, in particular to a luminescent material property prediction method, a luminescent material property prediction system, electronic equipment and a storage medium, wherein the luminescent material property prediction method comprises the following steps: pre-training the luminescent material molecular data without labels on a node level, wherein a training result is used as a first encoder; the method comprises the steps that a first encoder encodes luminescent material molecule data without labels, the labels extract predefined functional groups in luminescent material molecules from the luminescent material molecule data without labels, the functional groups are grouped and form sequences, the sequences are used as labels for self-supervision learning to be trained, and training results are used as a second encoder; and encoding the luminescent material molecular data to be predicted by using the second encoder, and predicting the property of the luminescent material to be predicted. By designing a modeling method of a node level and a graph level, the molecular structure is better characterized, and the problem of feature loss in the existing method is solved.)

1. A method for predicting a property of a luminescent material, comprising:

a first pre-training step: pre-training the luminescent material molecular data without labels on a node level, wherein a training result is used as a first encoder;

a second pre-training step: encoding the unlabeled luminescent material molecule data by using the first encoder, extracting predefined functional groups in the luminescent material molecules from the unlabeled luminescent material molecule data, wherein the functional groups are groups with preset functions and composed of chemical atoms, namely atom sets, grouping the functional groups and forming a sequence, training the sequence as a label for self-supervision learning, and taking a training result as a second encoder;

a prediction step: and encoding the luminescent material molecular data to be predicted by using the second encoder, and predicting the property of the luminescent material to be predicted.

2. The method according to claim 1, wherein the first pre-training step comprises the following steps:

the method comprises the following steps: selecting a molecule in the non-tag luminescent material, traversing all atoms in the molecule, selecting all atoms with the number of bonds more than or equal to 2 as central atoms to form a sequence Y, and taking the sequence Y as the first pre-trained tag sequence;

step two: traversing each atom in the sequence Y, selecting one atom as Y, taking Y as a center, and extracting k-layer neighbors and bonds near Y as substructures;

step three: covering atoms y of the extracted substructure, coding the rest part by using a graph neural network, taking the covered y atoms as a label for graph neural network training, and taking the rest part as the part of the extracted substructure with the covered atoms removed;

step four: training all central atoms in the sequence Y, and removing the central atoms which can not be converged or have converged errors larger than a preset value;

step five: repeating the steps from the first step to the fourth step for all molecules of the unlabeled luminescent material, and training a graph model based on a node level as the first encoder.

3. The method of claim 2, wherein the side information input by the graph neural network is a adjacency matrix of the substructure, and the node information is a feature matrix consisting of a type, a form charge, a number of hydrogen atoms connected, and a characteristic of each atom in the substructure, and whether the atom is a hetero-state atom.

4. The method according to claim 2, wherein the value of k is 2.

5. The method according to claim 1, wherein the second pre-training step comprises the following steps:

the method comprises the following steps: grouping the non-label luminescent material molecule functional groups according to the luminescent properties, carrying out fuzzy grouping on pre-training data according to the grouping result, and selecting one grouped luminescent material chemical molecule as a data set for each pre-training;

step two: encoding each atom in the luminescent material chemical molecules by using the first encoder, and accumulating the encoding of each atom to be used as the encoding of the final molecular level;

step three: extracting all functional groups under one group of the luminescent material chemical molecules to form a sequence F as a label sequence pre-trained on a molecular level;

step four: training the final molecular level code obtained in the step two and the functional group molecular level pre-trained label sequence obtained in the step three by using a multi-classification model;

step five: when the training of a grouped functional group is finished, evaluating the obtained graph model, and taking the evaluated graph model as a second encoder;

step six: and selecting functional groups of all other groups to repeat the steps two to five one by one, wherein the functional groups of each group are trained and evaluated to obtain a second encoder.

6. The method according to claim 1, wherein the predicting step comprises the steps of:

the method comprises the following steps: grouping according to the properties of the luminescent materials, selecting a second encoder corresponding to the luminescent properties to be predicted, and encoding the molecular data of the luminescent materials;

step two: inputting the obtained molecular code as a graph model, inputting the graph model into a multilayer perceptron, converting molecular properties into numerical data, and using the numerical data obtained by molecular property conversion as a correct label of the graph model;

step three: sequentially transmitting the numerical data to a multilayer perceptron to obtain a first probability that the luminous material molecular data actually output finally of the graph neural network has the predicted luminous property;

step four: calculating an error between a first probability that the luminescent material molecular data actually output last of the graph neural network has the predicted luminescent property and a second probability that the luminescent material molecular data actually has the predicted luminescent property, and judging whether the error is within an allowable range;

step five: if the error is within the allowable range, entering a sixth step, if the error is not within the allowable range, returning the error to the network, updating the network parameters, and returning to the third step;

step six: finishing training, carrying out evaluation test on the graph model, and modifying the hyper-parameters, the structure and the layer number of the graph model according to the test result to obtain the trained graph model;

step seven: and predicting the property of the luminescent material to be predicted by using the trained graph model.

7. The method for predicting the property of the luminescent material according to claim 6, wherein the luminescent property comprises one or more of a photoluminescence property, an electroluminescence property and a vibrator intensity.

8. A luminescent material property prediction system, comprising: a node pre-training system, a graph pre-training system and a molecular property prediction system;

the node pre-training system carries out self-supervision pre-training on a non-label luminescent material molecular structure, and a modeling method combines chemical characteristics of the luminescent material molecular structure to enable a pre-training model to learn the luminescent material molecular structure characteristics by taking k nearest neighbors as a basic unit to train to obtain a first encoder;

the graph pre-training system is used for grouping the functional groups aiming at the luminescent properties, training different pre-training models for the chemical properties of the functional groups in different groups, and training by adding the characteristics of the node level during pre-training by using the first encoder to obtain a second encoder;

the molecular property prediction system uses the second encoder to perform embedded encoding on the luminescent material molecules, and then uses the obtained second encoder to predict the properties of the luminescent material.

9. An electronic device, comprising a memory and a processor, the memory having a luminescent material property prediction program stored thereon, the luminescent material property prediction program when executed by the processor implementing the steps of the luminescent material property prediction method according to any one of claims 1 to 7.

10. A computer-readable storage medium, having a luminescent material property prediction program stored thereon, the luminescent material property prediction program being executable by one or more processors to implement the steps of the luminescent material property prediction method according to any one of claims 1 to 7.

Technical Field

The present invention relates to the field of data processing technologies, and in particular, to a method and a system for predicting properties of a luminescent material, an electronic device, and a storage medium.

Background

An organic electroluminescent material (hereinafter referred to as a light-emitting material) refers to a high molecular or small molecular organic material that can emit light under the action of an electric field. Organic light emitting molecules formed based on electron donors (donors) and electron acceptors (acceptors) have a very important position in the field of organic electroluminescent materials. The donor-acceptor type organic light-emitting molecules have the characteristic of charge transfer, so that the organic light-emitting molecules become an ideal system for regulating and controlling the excited state characteristics of the molecules, and based on the molecular design of the donor unit and the acceptor unit, the small singlet state-triplet state energy difference can be realized, and further the exciton utilization rate of 100% is realized. The traditional method can synthesize a luminescent material from a donor and an acceptor in a laboratory, and then verify the luminescent property of the molecule on the basis of obtaining the molecule. Through the personal experience of experiment developers, donors and acceptors with higher possibility can be preferentially selected, and the number of experiments is reduced.

However, the detection of the properties of the organic electroluminescent material based on the conventional method requires a lot of manpower, material resources and financial resources, and is extremely dependent on some imported equipment. For example, if there are 100 donors and 100 acceptors, there are at least 10000 combinations, and the sequential experimental verification takes a lot of time. Even though it is possible to select a donor and a receptor that are more effective depending on the personal experience of some developers, the method depending on the personal experience cannot be widely popularized.

As machine learning techniques have been developed worldwide, machine learning techniques have been applied to varying degrees in various research fields. In the face of some traditional problems, machine learning starts from the ideas of statistics, mathematics and computers, provides new ideas for many traditional subjects, and obtains certain achievements, such as the fields of remote sensing, medical images and code security. A series of techniques for predicting material properties based on machine learning methods have also emerged. However, although the deep learning method has been introduced to accelerate the progress of material prediction, the method heavily depends on a material performance relation table generated by a finite element model, and if the material performance to be predicted does not have high-quality data, the prediction is hardly possible, and the method is not popularized. The prediction accuracy of the technical method can only be kept at about 30%, and although the property prediction speed is accelerated, the prediction accuracy method still needs to be improved.

In summary, the existing luminescent material property prediction technology has the disadvantages of too high manual test cost, too much dependence on manual labeling on a prediction model, too low prediction accuracy, rough molecular structure modeling and the like.

Disclosure of Invention

The invention aims to provide a luminescent material property prediction method, aiming at overcoming the defects of low prediction accuracy and rough molecular structure modeling in the prior art.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a luminescent material property prediction method comprising:

a first pre-training step: pre-training the luminescent material molecular data without labels on a node level, wherein a training result is used as a first encoder;

a second pre-training step: encoding the unlabeled luminescent material molecule data by using the first encoder, extracting predefined functional groups in the luminescent material molecules from the unlabeled luminescent material molecule data, wherein the functional groups are groups with preset functions and composed of chemical atoms, namely atom sets, grouping the functional groups and forming a sequence, training the sequence as a label for self-supervision learning, and taking a training result as a second encoder;

a prediction step: and encoding the luminescent material molecular data to be predicted by using the second encoder, and predicting the property of the luminescent material to be predicted.

Further, the first pre-training step specifically includes the following steps:

the method comprises the following steps: selecting a molecule in the non-tag luminescent material, traversing all atoms in the molecule, selecting all atoms with the number of bonds more than or equal to 2 as central atoms to form a sequence Y, and taking the sequence Y as the first pre-trained tag sequence;

step two: traversing each atom in the sequence Y, selecting one atom as Y, taking Y as a center, and extracting k-layer neighbors and bonds near Y as substructures;

step three: covering atoms y of the extracted substructure, coding the rest part by using a graph neural network, taking the covered y atoms as a label for graph neural network training, and taking the rest part as the part of the extracted substructure with the covered atoms removed;

step four: training all central atoms in the sequence Y, and removing the central atoms which can not be converged or have converged errors larger than a preset value;

step five: repeating the steps from the first step to the fourth step for all molecules of the unlabeled luminescent material, and training a graph model based on a node level as the first encoder.

Further, the side information input by the graph neural network is an adjacency matrix of the substructure, and the node information is a feature matrix formed by the type, form charge, number of connected hydrogen atoms and the characteristic of whether each atom in the substructure is a hybrid atom.

Further, the value of k is 2.

Further, the second pre-training step specifically includes the following steps:

the method comprises the following steps: grouping the non-label luminescent material molecule functional groups according to the luminescent properties, carrying out fuzzy grouping on pre-training data according to the grouping result, and selecting one grouped luminescent material chemical molecule as a data set for each pre-training;

step two: and encoding each atom in the luminous material chemical molecule by using the first encoder, and accumulating the encoding of each atom to be used as the encoding of the final molecular level.

Step three: and extracting all functional groups under one group of the chemical molecules of the luminescent material to form a sequence F as a label sequence pre-trained on a molecular level.

Step four: training the final molecular level code obtained in the step two and the functional group molecular level pre-trained label sequence obtained in the step three by using a multi-classification model;

step five: when the training of a grouped functional group is finished, evaluating the obtained graph model, and taking the evaluated graph model as a second encoder;

step six: and selecting functional groups of all other groups to repeat the steps two to five one by one, wherein the functional groups of each group are trained and evaluated to obtain a second encoder.

Further, the predicting step specifically includes the steps of:

the method comprises the following steps: grouping according to the properties of the luminescent materials, selecting a second encoder corresponding to the luminescent properties to be predicted, and encoding the molecular data of the luminescent materials;

step two: inputting the obtained molecular code as a graph model, inputting the graph model into a multilayer perceptron, converting molecular properties into numerical data, and using the numerical data obtained by molecular property conversion as a correct label of the graph model;

step three: sequentially transmitting the numerical data to a multilayer perceptron to obtain a first probability that the luminous material molecular data actually output finally of the graph neural network has the predicted luminous property;

step four: calculating an error between a first probability that the luminescent material molecular data actually output last of the graph neural network has the predicted luminescent property and a second probability that the luminescent material molecular data actually has the predicted luminescent property, and judging whether the error is within an allowable range;

step five: if the error is within the allowable range, entering a sixth step, if the error is not within the allowable range, returning the error to the network, updating the network parameters, and returning to the third step;

step six: finishing training, carrying out evaluation test on the graph model, and modifying the hyper-parameters, the structure and the layer number of the graph model according to the test result to obtain the trained graph model;

step seven: and predicting the property of the luminescent material to be predicted by using the trained graph model.

Further, the light emitting property includes one or more of a photoluminescence property, an electroluminescence property, and a vibrator intensity.

Accordingly, there is also provided a luminescent material property prediction system comprising: a node pre-training system, a graph pre-training system and a molecular property prediction system;

the node pre-training system carries out self-supervision pre-training on a non-label luminescent material molecular structure, and a modeling method combines chemical characteristics of the luminescent material molecular structure to enable a pre-training model to learn the luminescent material molecular structure characteristics by taking k nearest neighbors as a basic unit to train to obtain a first encoder;

the graph pre-training system is used for grouping the functional groups aiming at the luminescent properties, training different pre-training models for the chemical properties of the functional groups in different groups, and training by adding the characteristics of the node level during pre-training by using the first encoder to obtain a second encoder;

the molecular property prediction system uses the second encoder to perform embedded encoding on the luminescent material molecules, and then uses the obtained second encoder to predict the properties of the luminescent material.

Accordingly, there is also provided an electronic device comprising a memory and a processor, the memory having stored thereon a luminescent material property prediction program, the luminescent material property prediction program when executed by the processor implementing the steps of the luminescent material property prediction method described above.

Accordingly, there is also provided a computer readable storage medium having a luminescent material property prediction program stored thereon, the luminescent material property prediction program being executable by one or more processors to implement the steps of the luminescent material property prediction method described above.

Compared with the prior art, the invention has the following beneficial effects:

the method for predicting the property of the luminescent material provided by the invention predicts the property of the luminescent material through deep learning, greatly reduces the experiment cost and accelerates the research and development speed. The node level self-supervision training learning method greatly reduces the cost of manual labeling and the requirement of machine learning on labeled data, and the graph level self-supervision training learning method greatly reduces the cost of manual labeling and the requirement of machine learning on labeled data.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic flow chart illustrating a method for predicting properties of a luminescent material according to an embodiment of the present invention;

FIG. 2 is a schematic flow diagram illustrating a refinement of a first pre-training step of the method for predicting properties of a luminescent material of FIG. 1;

FIG. 3 is a schematic flow diagram illustrating a refinement of a second pre-training step of the method for predicting properties of a luminescent material of FIG. 1;

FIG. 4 is a schematic flow diagram illustrating a refinement of the prediction step of the method for predicting properties of a luminescent material of FIG. 1;

FIG. 5 is a schematic structural diagram of a system for predicting properties of a luminescent material according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

It will also be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

Fig. 1 is a schematic flow chart illustrating a method for predicting properties of a luminescent material according to an embodiment of the present invention.

Referring to fig. 1, in the present embodiment, the method for predicting the property of the luminescent material specifically includes the following steps:

s01, first pre-training step

And pre-training the luminescent material molecular data without the label at a node level, wherein a training result is used as a first encoder.

S02, second pre-training step

The method comprises the steps of utilizing a first encoder to encode unlabeled luminescent material molecule data, extracting predefined functional groups in luminescent material molecules from the unlabeled luminescent material molecule data, grouping the functional groups into sequences, training the sequences as labels for self-supervision learning, and taking training results as a second encoder, wherein the functional groups are chemical atom groups and have preset functions.

S03, prediction step

And encoding the luminescent material molecular data to be predicted by using the second encoder, and predicting the property of the luminescent material to be predicted.

Specifically, the unlabeled light-emitting material molecule data input in step S01 are the 3D data structure and the SMILES expression of the light-emitting material molecule, and the input 3D data structure and SMILES expression data of the light-emitting material molecule are both the unlabeled data. The node pre-training system performs node-level pre-training on the input unlabeled luminescent material molecular data, and the final pre-training result is used as the encoder, i.e. the first encoder, of the graph pre-training system in the subsequent step S02.

Specifically, in step S02, the 3D data structure and SMILES expression of the luminescent material molecule are input to a graph pre-training system, which extracts predefined functional groups from the molecule, groups the molecules into a sequence according to the functional groups, pre-trains the sequence as a label for self-supervised learning, and uses the final pre-training result as an encoder of the downstream molecular property prediction system, i.e. a second encoder.

Specifically, in step S03, tagged data, which is a sequence of functional groups extracted from the luminescent material molecular data by rdkit, is input; and encoding the luminescent material molecular data to be predicted by using a second encoder pre-trained by the graph pre-training system, and predicting the luminescent property of the luminescent material by using the encoded vector as the training input to obtain a prediction result, wherein the molecular property prediction system is a multilayer perceptron model. According to the prediction result, the research and development personnel adjust the research and development direction and select the structure with the highest possibility for research and development.

In this embodiment, the first encoder and the second encoder are used for converting the input luminescent material molecular data from a molecular format to a format of a graph model through the graph model.

In the present embodiment, the properties of the luminescent material mainly include the following properties: (1) photoluminescent properties such as photoluminescence wavelength, fluorescence quantum yield; (2) electroluminescent properties such as electroluminescent wavelength, external quantum efficiency; (3) a melting point, such as the melting point, boiling point of an organic molecule; (4) and (4) the strength of the oscillator.

SMILESS (simplified molecular input line entry specification), a specification for explicitly describing the structure of molecules using ASCII strings. Smiles was developed by Arthur Weininger and David Weininger in the late 80's of the 20 th century and modified and expanded by others.

Since SMILESS uses a string of characters to describe a three-dimensional chemical structure, it must convert the chemical structure into a spanning tree, and the system uses a vertical-first traversal tree algorithm. During the conversion, hydrogen is removed and the ring is opened. When indicated, the atom at the end of the bond that is cleaved is indicated by a number and the branch is shown in parentheses.

The smiles string can be imported and converted by most molecular editing software into a two-dimensional graph or a three-dimensional model of a molecule. The conversion to two-dimensional graphics can be done using Helson's "Structure image Generation algorithms" (Structure Diagram Generation algorithms).

By grouping and predicting the photoluminescence property and the electroluminescence property of the luminescent material, research personnel can evaluate the luminescent property of the luminescent material and provide suggestions for subsequent research and development directions.

Fig. 2 is a schematic flow chart illustrating a detailed process of the first pre-training step of the method for predicting properties of luminescent materials in fig. 1.

In this embodiment, the node pre-training system performs feature extraction on each node in the graph, the substructure composed of k-layer atoms and bonds that are nearest to the node, where the node refers to an atom in a molecule, and then inputs the entire substructure into a Graph Neural Network (GNN) for training, and the node at the center of the substructure is used as a training label.

As shown in fig. 2, in this embodiment, the step S01 specifically includes the following steps:

s011: selecting one molecule in the non-label luminescent material, traversing all atoms in the molecule, selecting all atoms with the number of bonds more than or equal to 2 as central atoms to form a sequence Y, and taking the sequence Y as the first pre-trained label sequence;

many atoms having 1 bond number are H atoms, and only one bond indicates that there are too few features (for example, bonds, adjacent atoms) available around the bond, and the prediction effect is poor, so that atoms having 2 or more bonds are selected as the central atoms.

S012: traversing each atom in the sequence Y, selecting one atom as Y, taking Y as a center, extracting k-layer neighbors and bonds near Y as substructures, wherein k is generally 2;

one molecular structure comprises a plurality of atoms, and the substructure refers to a structure formed by k-layer neighbors and bonds of one atom;

s013: covering atoms y of the extracted substructure, coding the rest part by using a graph neural network, taking the covered y atoms as a label for graph neural network training, and taking the rest part as the part of the extracted substructure with the covered atoms removed;

specifically, the atom y is covered (mask) by the substructure extracted in step S012, the rest is encoded by using the graph neural network, and the covered y atom is used as a label for graph neural network training. The side information input by the graph neural network is an adjacency matrix of the substructure, and the node information is a feature matrix formed by atomic features such as the type, form charge, the number of connected hydrogen atoms and whether the atom features are in a hybrid state or not of each atom in the substructure.

S014: training all central atoms in the sequence Y, and removing the central atoms which can not be converged or have converged errors larger than a preset value;

s015: repeating the steps S011 to S014 for all the molecules of the unlabeled luminescent material, and training a node level-based graph model as the first encoder.

In the modeling of the graph model, the embodiment of the invention combines the characteristics of chemical molecules, not uses a single atom as a basic unit of the graph model, but considers the overall characteristics of a substructure consisting of the atom and the nearest neighbor of the surrounding k layers, and the design of the graph model fully considers the objective rule of the chemical molecules, namely that the single atom has no property, but a specific group consisting of a plurality of atoms can influence the property of the molecule.

Fig. 3 is a schematic flow chart illustrating a detailed pre-training step of the method for predicting properties of luminescent material in fig. 1.

In this embodiment, the graph pre-training system will encode the molecules using the node feature extractor of the node pre-training system. All the pre-training data used in step S02 and step S01 are mutually exclusive, i.e., two completely different sets of data are used in step S01 and step S02, and all the molecules used in step S02 have functional groups associated with luminescence properties. The functional groups have obvious characteristics and can be extracted automatically through some third-party software or algorithm, such as RDkit. The embodiment of the invention can preset related functional group groups in advance, and also group molecules with certain functional groups. In the embodiment of the invention, each node in the molecule is coded by using the feature extractor, and then the result of each atom code is accumulated to be used as the final code of the molecular level. In the actual operation process, the molecular level code can also be obtained by averaging the results of each atomic code or splicing the feature matrix, or by training with a full connection layer. And finally, using a multi-classification model and using the extracted molecular functional groups as labels to perform prediction.

Specifically, as shown in fig. 3, in this embodiment, the step S02 specifically includes the following steps:

s021: grouping the non-label luminescent material molecule functional groups according to the luminescent properties, carrying out fuzzy grouping on pre-training data according to the grouping result, and selecting one grouped luminescent material chemical molecule as a data set of each pre-training;

fuzzy grouping means that the luminescent properties of functional groups according to which the grouping is based are not fixed, and the results of the obtained grouping are fuzzy;

specifically, the properties of the luminescent material mainly include the following properties: (1) photoluminescent properties such as photoluminescence wavelength, fluorescence quantum yield; (2) electroluminescent properties such as electroluminescent wavelength, external quantum efficiency; (3) a melting point, such as the melting point, boiling point of an organic molecule; (4) and (4) the strength of the oscillator.

S022: encoding each atom in the luminescent material chemical molecules by using a first encoder, and accumulating the encoding of each atom to be used as the encoding of the final molecular level;

s023: extracting all functional groups under one group of the luminescent material chemical molecules to form a sequence F as a label sequence pre-trained on a molecular level;

a sequence of tags refers to an ordered collection of a stack of tags.

S024: training the final molecular level code obtained in step S022 and the pre-trained tag sequence of the functional group molecular level obtained in step S023 by using a multi-classification model;

wherein the multi-classification model can predict multiple classes of luminescent properties, more than two classes of luminescent properties.

S025: when the training of a grouped functional group is finished, evaluating the obtained graph model, and taking the evaluated graph model as a second encoder;

in this embodiment, when each group of functional groups is trained, a plurality of different graph models are obtained correspondingly, so that the graph models obtained through training need to be evaluated, specifically, the prediction accuracy of the graph model on the functional group sequence is evaluated, that is, the prediction accuracy after the group of functional group sequences is trained is evaluated, and finally, only one graph model with the best accuracy is selected as the second encoder, that is, the graph model passing the evaluation is selected as the second encoder, and other graph models do not pass the evaluation, and therefore cannot be used as the second encoder.

In this embodiment, the estimation method of the prediction accuracy of the graph model is not limited, and for example, the estimation method may be a comprehensive estimation method based on the accuracy and recall rate of the output result of each graph model, or a measurement and estimation method using a known functional group input into the graph model.

S026: and selecting other functional groups of all the groups, and repeating the steps S022-S025 one by one, wherein the functional groups of each group are trained and evaluated to obtain a second encoder.

In this embodiment, the remaining untrained groups of functional groups need to be processed in one round of steps S022-S025, the pre-training is finished after step S026 is executed, and after the functional group training evaluation of each group, a second encoder is obtained, for example, 5 groups of functional groups are pre-trained, and then 5 second encoders are obtained after the pre-training is finished, that is, 5 second encoders correspond to 5 groups of functional groups.

In the modeling of the graph model, the embodiment of the invention combines the characteristics of chemical molecules, does not take a single atom as a basic unit of the graph model, and considers the overall characteristics of a substructure consisting of the atom and the nearest neighbor of the surrounding k layers. Such a graphical model design takes into full account the objective laws of chemical molecules, i.e., a single atom does not have properties, but a specific group consisting of multiple atoms can affect the properties of the molecule.

In the pre-training method at the graph level, the characteristics of the chemical molecules are combined again, the chemical properties of the molecules should not be uniform, and the different chemical properties are distinguished and associated, so that the associated properties in the chemical molecules are grouped, such as the light-emitting wavelength and the light-emitting efficiency of the molecules, so that the model is constrained in the similar direction in the training process. The grouping of the chemical properties of the embodiments of the present invention is accomplished by manual grouping.

In the face of the problem of machine learning technology data shortage, the embodiment of the invention also provides two methods for automatically acquiring the label: one is in the node level modeling, automatically covering (mask) a certain atom as a label of the self-supervision learning, taking a substructure formed by nearest neighbors of a k layer of the atom as an input characteristic, and carrying out the self-supervision learning; the other method is to use a molecular functional group list as a molecular self-supervision learning label in the modeling of the layer surface.

Fig. 4 is a schematic flowchart of a detailed prediction step of the luminescent material property prediction method in fig. 1, in which the molecular property prediction system according to the embodiment of the present invention encodes an input molecular 3D graph structure based on a molecular feature extractor trained by an upstream pre-training task, and then predicts the molecular properties of the whole graph structure by using a multi-layer perceptron (MLP).

Specifically, as shown in fig. 4, in this embodiment, the step S03 specifically includes the following steps:

s031: grouping according to the properties of the luminescent materials, selecting a second encoder corresponding to the luminescent properties to be predicted, and encoding the molecular data of the luminescent materials;

s032: inputting the obtained molecular code as a graph model, inputting the graph model into a multilayer perceptron, converting molecular properties into numerical data, and using the numerical data obtained by molecular property conversion as a correct label of the graph model;

in this embodiment, in order to distinguish different molecules having the same molecular property, the molecular property needs to be further quantified. The luminous efficiency of the different luminescent materials is exemplified. For example, the luminous efficiency of the luminescent material a is 0.23 after quantization, the luminous efficiency of the luminescent material B is 0.47 after quantization, and the value of the molecular property after quantization is used as the correct label of the graph model.

S033: sequentially transmitting the numerical data to a multilayer perceptron to obtain a first probability that the luminous material molecular data actually output finally of the graph neural network has the predicted luminous property;

s034: calculating an error between a first probability that the luminescent material molecular data actually output last of the graph neural network has the predicted luminescent property and a second probability that the luminescent material molecular data actually has the predicted luminescent property, and judging whether the error is within an allowable range;

for example: the luminescent material molecular data actually has the luminescent property of the predicted property, i.e. the second probability is 1, and the probability that the luminescent material molecular data actually output last of the graph neural network has the predicted luminescent property is 0.4, i.e. the first probability is 0.4, and the error is 1-0.4- = 0.6. If the set tolerance is less than or equal to 0.3, then 0.6 is greater than 0.3, and the error is not within the tolerance, so the error needs to be sent back to the network, the network parameters are updated, and the step S033 is returned. And if the error is within the allowable range, the procedure goes to step S036 to finish the training.

S035: if the error is within the allowable range, the step S036 is performed, and if the error is not within the allowable range, the error is returned to the network, the network parameters are updated, and the step S033 is returned;

s036: finishing training, carrying out evaluation test on the graph model, and modifying the hyper-parameters, the structure and the layer number of the graph model according to the test result to obtain the trained graph model;

the hyper-parameters, the structure and the layer number of the graph model are the concepts of machine learning, and the parameters can be modified manually.

S037: and predicting the property of the luminescent material to be predicted by using the trained graph model.

The material research and development personnel adjust the research and development direction of the material or verify the actual property of the recommended material according to the result of the molecular property prediction system.

In a specific implementation process, after obtaining the prediction result of the deep learning system, a material research and development staff can perform a small amount of experiments for verification, and finally determine the subsequent research and development direction according to the verification result.

The embodiment of the invention comprises three parts: modeling a molecular graph model, pre-training the molecular graph model and predicting the property of the luminescent material based on the molecular graph model.

In the molecular graph model modeling, a molecule is modeled from two dimensions of a node level and a layer level of a graph model at the same time. At present, a luminescent material property prediction method based on a graph model usually focuses on atom level modeling and trains each atom and a bond connected with the atom. However, the property of the luminescent material often depends on the mutual structure of a plurality of atoms in a molecule, and if modeling is performed only on a single atom or bond, the modeling is not enough to characterize the structural features inside the molecule, but the modeling of the local structure can better characterize the structural features of the molecule, so in the node level modeling of this embodiment, the structural properties of each atom and its surrounding k-layer neighbor nodes are modeled by using the nearest neighbor idea. In addition to modeling at the molecular node level, the luminescent material property prediction method models the whole molecule, performs graph characterization, and then performs luminescent material property prediction at the graph characterization level of the whole molecule.

The embodiment of the present invention provides a method for predicting properties of a luminescent material based on a graph, and the embodiment considers that chemical properties of molecules have a certain correlation with each other, for example, in predicting the luminescent properties of the luminescent material, properties such as the wavelength of luminescence, the efficiency of luminescence, and the intensity of luminescence of the luminescent material molecules have a certain correlation with each other, so that different pre-training needs to be performed for predicting the properties of the luminescent material in a specific field. The embodiment of the invention utilizes the personal experience of chemical researchers to group 30 common chemical properties, for example, four properties of luminous wavelength, luminous color, luminous efficiency and molecular vibration intensity of luminous material molecules are classified into one group, and a computational chemical tool, for example, RDkit is utilized to screen out all functional groups (functional groups) related to the large properties in the luminous material molecules, and the functional groups of the luminous material molecules are grouped into a sequence to be used as a multi-classification supervision learning label for layer surface modeling for training.

When the machine learning technology is applied to other fields, the problems of data shortage, data difficult characterization and the like are often faced, so the embodiment provides a graph model pre-training method in the chemical molecular field. Firstly, collecting an open-source label-free molecular data set, automatically generating label-free luminescent material molecular data according to a certain rule, and then automatically constructing a label of a pre-training model according to chemical properties. In this embodiment, for the graph model modeling method at the node level, an atom is covered (mask) as a training label, and then self-supervised learning is performed by using the structural features of the substructure formed by k layers of neighboring nodes. After the pre-training of the node level graph model is finished, an encoder (encoder) of a node level can be obtained, each atom in a molecule is embedded (embedding) by using the encoder, and finally, the encoder is accumulated to be used as a vector (vector) after the molecule is encoded, and meanwhile, the extracted molecular functional group is used as a multi-classification supervised learning label of the molecule. According to the established luminescent material molecular property classification table, each training only aims at the functional groups under the same property classification. Because the functional group is easy to obtain and does not need manual labeling, a large amount of label data can be obtained in a short time and used for supervised learning pre-training at a graph level. According to the grouping of the chemical property functional groups, each group of the functional groups is pre-trained to form a pre-training model.

After the pre-training is finished, different pre-training models are loaded according to the grouping of the chemical properties to be predicted, and then the light-emitting material property prediction model is trained through fine-tune (fine-tune) in a small data set, so that the property prediction of the light-emitting material is realized.

FIG. 5 is a schematic structural diagram of an embodiment of a system for predicting properties of a luminescent material according to the present invention.

Referring to fig. 5, the luminescent material property prediction system of the present embodiment is used to implement the steps of the luminescent material property prediction method, and specifically includes a node pre-training system, a graph pre-training system, and a molecular property prediction system.

In this embodiment, the node pre-training system is used to implement the first pre-training step in the luminescent material property prediction method. The node pre-training system carries out self-supervision pre-training on the molecular structure of the non-label luminescent material, the modeling method combines the chemical characteristics of the molecular structure of the luminescent material, the pre-training model learns the molecular structure characteristics of the luminescent material by taking k neighbor as a basic unit, and the first encoder is obtained through training.

In this embodiment, the graph pre-training system is used to implement the second pre-training step in the luminescent material property prediction method. The graph pre-training system groups the functional groups according to the luminescent properties, trains different pre-training models according to the chemical properties of the functional groups grouped differently, trains by using the first encoder, adds the characteristics of the node layer during pre-training, trains to obtain the second encoder, and enables the characteristics of the node layer and the graph layer to be better fused.

In this embodiment, the molecular property prediction system is used to implement the prediction step in the luminescent material property prediction method. The molecular property prediction system uses the second encoder to perform embedded encoding on the luminescent material molecular data, and then uses the obtained second encoder to predict the luminescent material property. In particular, the present embodiment pre-training phase receives as input a 3D data structure of luminescent material molecules. In other embodiments, the luminescent material molecular data may have other expression forms, such as three-dimensional coordinates, SMILES, etc., which may be converted into a 3D data structure, but some of the data may be lost with some degree of accuracy. Since very accurate data is not required in the pre-training phase, the data is uniformly converted into a 3D data structure as a pre-training input. And in the downstream luminescent material property prediction stage, only the accurate 3D data structure of the luminescent material molecules and the luminescent material property to be predicted are used as input and prediction labels.

The invention also provides an embodiment of an electronic device, which includes a memory and a processor, wherein the memory stores a luminescent material property prediction program, and the luminescent material property prediction program implements the steps of the luminescent material property prediction method when executed by the processor.

The present invention also provides an embodiment of a computer-readable storage medium having a luminescent material property prediction program stored thereon, the luminescent material property prediction program being executable by one or more processors to implement the steps of the above-described luminescent material property prediction method. The processor typically includes a single-chip microcomputer including non-volatile and/or volatile memory. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchronous Link DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

According to the embodiment of the invention, the properties of the luminescent material are predicted through deep learning, so that the experiment cost is greatly reduced, and the research and development speed is accelerated. By designing a modeling method at a node level and a graph level, a molecular structure is better characterized, and the problem of feature loss in the previous methods is solved. By the two self-supervision pre-training methods, the problem of lack of machine learning label data is relieved, the cost of manual labeling is reduced, and a complete set of complete solution is designed for the pre-training stage.

In summary, the above-mentioned embodiments of the present invention are only preferred embodiments of the present invention, and not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the specification and the drawings, or other related technical fields directly/indirectly applied to the present invention are included in the scope of the present invention.