阅读说明：本技术 一种全无机钙钛矿光电探测器及其制备方法 (All-inorganic perovskite photoelectric detector and preparation method thereof ) 是由 廖广兰 刘星月 刘智勇 孙博 谭先林 史铁林 于 2020-03-19 设计创作，主要内容包括：本发明属于微纳制造相关技术领域,其公开了一种全无机钙钛矿光电探测器及其制备方法,所述光电探测器包括玻璃基底、CuPc空穴传输层、CsPbBr<Sub>3</Sub>钙钛矿薄膜、MoO<Sub>x</Sub>修饰层及Ag电极层,所述玻璃基底包括基底及形成在所述基底上的ITO导电层；所述CuPc空穴传输层形成在所述ITO导电层远离所述基底的表面上；所述CsPbBr<Sub>3</Sub>钙钛矿薄膜形成在所述CuPc空穴传输层远离所述ITO导电层的表面上；所述MoO<Sub>x</Sub>修饰层形成在所述CsPbBr<Sub>3</Sub>钙钛矿薄膜远离所述CuPc空穴传输层的表面上；所述Ag电极层形成在所述MoO<Sub>x</Sub>修饰层远离所述CsPbBr<Sub>3</Sub>钙钛矿薄膜的表面上。本发明的生产成本低,适用性好,尤其适合大面积器件及器件阵列的高效制备。(The invention belongs to the technical field related to micro-nano manufacturing, and discloses an all-inorganic perovskite photoelectric detector and a preparation method thereof 3 Perovskite thin film, MoO x The glass substrate comprises a substrate and an ITO conducting layer formed on the substrate; the CuPc hole transport layer is formed on the surface of the ITO conductive layer, which is far away from the substrate; the CsPbBr 3 The perovskite thin film is formed on the surface of the CuPc hole transport layer away from the ITO conductive layer; the MoO x A modifier layer formed on the CsPbBr 3 Surface of perovskite thin film far away from CuPc hole transport layerOn the surface; the Ag electrode layer is formed on the MoO x The modification layer is far away from CsPbBr 3 On the surface of the perovskite thin film. The invention has low production cost and good applicability, and is particularly suitable for the high-efficiency preparation of large-area devices and device arrays.)

1. An all-inorganic perovskite photodetector is characterized in that:

the photoelectric detector is a laminated structure stacked along the thickness direction thereof and comprises a glass substrate, a CuPc hole transport layer and CsPbBr₃Perovskite thin film, MoO_xThe glass substrate comprises a substrate and an ITO conducting layer formed on the substrate; the CuPc hole transport layer is formed on the ITO conductive layer; the CsPbBr₃The perovskite thin film is formed on the surface of the CuPc hole transport layer; the MoO_xA modifier layer formed on the CsPbBr₃On the perovskite film; the Ag electrode layer is formed on the MoO_xAnd (4) a decorative layer.

2. The all-inorganic perovskite photodetector of claim 1, wherein: the CsPbBr₃The perovskite film is formed by sequentially evaporating PbBr₂The precursor layer and the CsBr precursor layer are formed by reaction under annealing.

3. The all-inorganic perovskite photodetector of claim 2, wherein: PbBr₂The thickness of the layer is 150-200 nm, and the thickness of the CsBr layer is 115-150 nm.

4. The all-inorganic perovskite photodetector of claim 1, wherein: the thickness of the CuPc hole transport layer is 6-10 nm.

5. The all-inorganic perovskite photodetector of claim 1, wherein: the MoO_xThe thickness of the modification layer is 4-8 nm.

6. The all-inorganic perovskite photodetector of any one of claims 1 to 5, wherein: the thickness of the Ag electrode layer is 110-120 nm.

7. A method of making an all inorganic perovskite photodetector as claimed in any one of claims 1 to 6, comprising the steps of:

(1) providing a glass substrate, and preparing a CuPc hole transport layer on an ITO conductive layer of the glass substrate by adopting an evaporation process;

(2) method for preparing CsPbBr on CuPc hole transport layer by continuous evaporation process₃A perovskite thin film;

(3) adopts the evaporation process in CsPbBr₃Deposition of MoO on perovskite thin films_xA finishing layer;

(4) in MoO by adopting evaporation process_xAnd depositing an Ag electrode layer on the modification layer, thereby completing the preparation of the photoelectric detector.

8. The method of claim 7, wherein the CuPc hole transport layer is formed under a pressure of less than 9 × 10^-4Pa in a vacuum chamber at an evaporation rate of

9. The method of making an all-inorganic perovskite photodetector as claimed in claim 7, wherein: in the step (2), firstly, PbBr is vapor-plated on the CuPc hole transport layer₂A precursor layer, and evaporating a CsBr precursor layer again; finally, annealing for 7-10min at 250-270 ℃ in the air to obtain CsPbBr₃A perovskite thin film; wherein, PbBr₂The evaporation rates of the layer and CsBr layer are both

10. The method for preparing an all-inorganic perovskite photodetector as claimed in claim 7, wherein the step (4) is carried out at a pressure of less than 9 × 10^-4Pa in a vacuum chamber at an evaporation rate of

Technical Field

The invention belongs to the technical field related to micro-nano manufacturing, and particularly relates to an all-inorganic perovskite photoelectric detector and a preparation method thereof.

Background

The photoelectric detector is the most important component of modern photoelectric systems, is widely applied to national defense safety and people life, and has important functions in systems such as optical fiber communication, industrial flaw detection, medical imaging, infrared early warning, space detection and the like, and devices such as optical fiber communication, remote controllers, face recognition, cameras and the like. At present, commercial photodetectors are mainly constructed on the basis of traditional inorganic semiconductor materials such as Si, InGaAs, GaN and the like, and have the problems of poor weak light responsivity and the like. The inorganic semiconductor films of Si, InGaAs, GaN and the like adopted by the device are mostly prepared by molecular beam epitaxy and metal organic chemical vapor deposition processes, the requirements on production equipment are high, the production cost is high, the process temperature is high (often higher than 1000 ℃), the energy consumption is high, and the preparation of the flexible photoelectric detector and the application of the flexible photoelectric detector in a flexible electronic system are limited. Due to the unique photoelectric characteristics and the easiness in preparation by a solution method (spin coating, ink-jet printing or screen printing and the like), the novel organic or quantum dot light detection material gains more and more attention in the field of photoelectric detection. However, such materials are generally limited by low carrier mobility, and photodetectors prepared based on the materials generally have low response rate, and are difficult to meet the requirements of high frame frequency photoresponse in high-speed imaging and high-speed communication systems.

The all-inorganic perovskite material is a good material in the field of photoelectronic technology due to its unique optoelectronic properties, such as excellent photoconductivity, dipole charge transport property, adjustable forbidden band, high light absorption coefficient, low exciton binding energy and the like, and excellent stability (especially thermal stability). The photoelectric detector using the all-inorganic perovskite material as the photosensitive layer shows excellent photoresponse and working stability, and the response time is as low as tens of nanoseconds, so that the photoelectric detector has great development potential in the field of photoelectric detection.

All-inorganic perovskite photodetectors are mainly classified into two types: photoconductive and photovoltaic. The longer transmission distance of carriers in the photoconductive device leads to longer optical response time (hundreds of microseconds to several milliseconds) of the device, and limits the application of the device in high-frequency optical signal detection. The photovoltaic photoelectric detector has the advantages of self-energy supply, high response speed (nanosecond level), high detection rate and the like, simplifies the complexity of a photoelectric system because an external power supply device is not needed, and has huge development potential in the field of high-frequency light detection. However, the high performance of the devices is often based on the use of electron transport layers and hole transport layers (PTAA, P3HT) which are high in energy consumption or expensive, and the use of these materials greatly increases the production cost of the devices, limiting the commercial popularization thereof. In addition, most of the traditional all-inorganic perovskite thin films are prepared based on a solution method, and have the defects of difficult synthesis of inorganic perovskite materials, high defect state density of the thin films, poor film forming property and the like, the defects are not favorable for rapid carrier migration, and the solution method process is not favorable for preparing large-area perovskite thin films and also limits the preparation of large-area photoelectric detectors. Accordingly, there is a need in the art to develop a low-cost, high-performance perovskite photodetector and a method for fabricating the same.

Disclosure of Invention

Aiming at the defects or the improvement requirements of the prior art, the invention provides a low-cost and high-performance all-inorganic perovskite photoelectric detector and a preparation method thereof based on the working characteristics of the photoelectric detector, wherein the preparation method adopts an evaporation process to prepare all functional layers or precursor layers of the photoelectric detector, and a continuous evaporation process is adopted to prepare high-quality CsPbBr₃Perovskite thin film by fine tuningPbBr₂Thickness of CsPbBr precursor layer to realize CsPbBr₃Accurate control of film components, CsPbBr prepared by the method₃The film is compared with CsPbBr prepared by the traditional solution method₃The film is more uniform, has higher crystallinity, higher coverage rate, longer carrier service life, fewer internal defects and the like, and is beneficial to the transmission of carriers. Meanwhile, in the photoelectric detector, a cheap p-type CuPc material is adopted to replace an expensive organic micromolecular hole transport material, so that the overall cost of the device can be effectively reduced, the stability of the device can be improved, the carrier mobility of the device can be promoted, and the optical detection performance of the device can be improved. In addition, inexpensive MoO was introduced_xModification layer pair CsPbBr₃Defects of the perovskite thin film are passivated, unfavorable non-radiative coincidence loss is reduced, and the carrier transmission rate and the photoresponse rate of the photoelectric detector are further improved.

To achieve the above object, according to one aspect of the present invention, there is provided an all-inorganic perovskite photodetector having a stacked layered structure including a glass substrate, a CuPc hole transport layer, and CsPbBr₃Perovskite thin film, MoO_xThe glass substrate comprises a substrate and an ITO conducting layer formed on the substrate; the CuPc hole transport layer is formed on the surface of the ITO conductive layer, which is far away from the substrate; the CsPbBr₃The perovskite thin film is formed on the surface of the CuPc hole transport layer away from the ITO conductive layer; the MoO_xA modifier layer formed on the CsPbBr₃The surface of the perovskite thin film, which is far away from the CuPc hole transport layer; the Ag electrode layer is formed on the MoO_xThe modification layer is far away from CsPbBr₃On the surface of the perovskite thin film.

Further, the CsPbBr₃The perovskite film is formed by sequentially evaporating PbBr₂The precursor layer and the CsBr precursor layer are formed by reaction under annealing.

Further, PbBr₂The thickness of the layer is 150-200 nm, and the thickness of the CsBr layer is 115-150 nm.

Further, the thickness of the CuPc hole transport layer is 6-10 nm.

Further, the MoO_xThe thickness of the modification layer is 4-8 nm.

Furthermore, the thickness of the Ag electrode layer is 110-120 nm.

According to another aspect of the present invention, there is provided a method of fabricating an all-inorganic perovskite photodetector, the method comprising the steps of:

(1) providing a glass substrate, and preparing a CuPc hole transport layer on an ITO conductive layer of the glass substrate by adopting an evaporation process;

(2) method for preparing CsPbBr on CuPc hole transport layer by continuous evaporation process₃A perovskite thin film;

(3) adopts the evaporation process in CsPbBr₃Deposition of MoO on perovskite thin films_xA finishing layer;

(4) in MoO by adopting evaporation process_xAnd depositing an Ag electrode layer on the modification layer, thereby completing the preparation of the photoelectric detector.

Further, the preparation of the CuPc hole transport layer is carried out under a pressure of less than 9 × 10^-4Pa in a vacuum chamber at an evaporation rate of

Further, in the step (2), first, PbBr is vapor-deposited on the CuPc hole transport layer₂A precursor layer, and evaporating a CsBr precursor layer again; finally, annealing for 7-10min at 250-270 ℃ in the air to obtain CsPbBr₃A perovskite thin film; wherein, PbBr₂The evaporation rates of the layer and CsBr layer are both

Further, the step (4) is to use the pressure of less than 9 × 10^-4Pa in a vacuum chamber at an evaporation rate of

In general, compared with the prior art, the all-inorganic perovskite photoelectric detector and the preparation method thereof provided by the invention have the following beneficial effects:

1. all functional layers or precursor layers of the photoelectric detector are prepared by an evaporation process, so that the requirement on equipment is low (only one thermal evaporation equipment is needed), and the efficient preparation of a large-area photoelectric detection device or a photoelectric detector array is facilitated; the whole process has strong applicability, low process complexity, high repetition rate and high preparation efficiency, and is convenient for large-scale commercial production of the photoelectric detector.

2. The CsPbBr₃The perovskite film is prepared by continuous evaporation of PbBr₂The precursor layer and the CsBr precursor layer are prepared by high-temperature annealing, and the CsPbBr can be accurately controlled by adjusting the thicknesses of the CsBr layer and the CsBr layer₃Phase composition of the film; compared with the traditional solution method, the method has the advantages of more controllable process and stronger repeatability, and the CsPbBr prepared by the method₃Compared with CsPbBr prepared by traditional solution method, the perovskite film₃The perovskite film has higher film quality and better optical and electrical properties, and is based on the evaporated CsPbBr₃The photoelectric detector prepared from the perovskite thin film has more excellent optical detection performance. In addition, the method does not use any toxic solvent, and is environment-friendly.

3. The photoelectric detector provided by the invention adopts cheap and highly hydrophobic CuPc as a hole transport material to replace the commonly used expensive hole transport material (such as Spiro-OMeTAD, PTAA, P3HT and the like), and does not use any hole transport material, thereby being beneficial to reducing the overall production cost and promoting the commercial application of the photoelectric detector; in addition, the CuPc has higher hydrophobicity and chemical stability compared with the common hole transport material, so that the service life of the device is prolonged.

4. Introducing ultra-thin MoO_xModification layer pair CsPbBr₃The perovskite film is modified, so that CsPbBr can be effectively passivated₃Bulk defects and surface defects of the perovskite thin film, remarkably reduce the non-radiative recombination rate and dark current density of carriers, and MoO_xThe layer can also effectively lowerLow CsPbBr₃And an interface potential barrier between the photosensitive layer and the Ag electrode layer improves the carrier transmission and extraction efficiency, so that high-speed and high-sensitivity light detection is realized.

5. The designed perovskite photoelectric detector is a longitudinally-stacked photovoltaic (self-powered) type device, and the device can perform optical detection autonomously without an external power supply, so that the energy consumption and complexity of the system are reduced, and the overall cost is further reduced.

Drawings

FIG. 1 is a cross-sectional view of an all-inorganic perovskite photodetector provided by the present invention;

FIG. 2 is a schematic flow chart of a preparation method of the all-inorganic perovskite photodetector provided by the invention.

The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein: 1-glass substrate, 2-ITO conductive layer, 3-CuPc hole transport layer, 4-CsPbBr₃Perovskite thin film, 5-MoO_xA decoration layer, a 6-Ag electrode layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, the all-inorganic perovskite photodetector provided by the present invention is a layered structure stacked along the thickness direction thereof, and includes a glass substrate 1, a CuPc hole transport layer 3, and CsPbBr₃Perovskite thin film 4, MoO_xThe glass substrate 1 comprises a substrate and an ITO conducting layer 2 formed on the substrate. The CuPc hole transport layer 3 is formed on the surface of the ITO conductive layer 2 far away from the substrate. The CsPbBr₃A perovskite thin film 4 is formed on the surface of the CuPc hole transport layer 3 away from the ITO conductive layer 2. The MoO_xA modifying layer 5 formed on the CsPbBr₃The perovskite thin film 4 is far away from the surface of the CuPc hole transport layer 3; the Ag electrode layer 6 is formed on the MoO_xThe modification layer 5 is far away from CsPbBr₃On the surface of the perovskite thin film 4.

In this embodiment, compared with a common organic small molecule hole transport layer (PTTA, P3HT, etc.), the CuPc hole transport layer 3 has lower material cost and higher hydrophobicity, which is beneficial to reducing the overall cost of the device and improving the stability; the CsPbBr₃The perovskite film 4 is formed by sequentially evaporating PbBr₂The precursor layer and the CsBr precursor layer are generated by reaction under high-temperature annealing; the MoO_xThe modification layer 5 can effectively passivate CsPbBr₃Defects of the perovskite thin film reduce the non-radiative recombination rate and the dark current density of a current carrier; at the same time, the MoO_xThe modification layer 5 can also reduce CsPbBr₃The interface potential barrier between the perovskite thin film 4 and the Ag electrode layer 6 is beneficial to the effective transmission of current carriers, and further high-performance optical detection is realized.

The thickness of the CuPc hole transport layer 3 is 6-10 nm, and the evaporated PbBr₂The thickness of the layer is 150-200 nm, and the thickness of the evaporated CsBr layer is 115-150 nm; the MoO_xThe thickness of the modification layer is 4-8 nm; the thickness of the Ag electrode layer 6 is 110-120 nm.

The invention also provides a preparation method of the all-inorganic perovskite photoelectric detector, which comprises the following steps:

step one, providing a glass substrate with an ITO conductive layer, and cleaning the glass substrate.

Specifically, providing a glass substrate with an ITO conductive layer, carrying out ultrasonic cleaning on the glass substrate with the ITO conductive layer for 15-20 min by using a cleaning agent, acetone, ethanol and deionized water in sequence, and using N₂And blowing the glass substrate by air flow, and then carrying out ultraviolet ozone treatment on the glass substrate for 25-30 min.

And secondly, preparing a hole transport layer on the ITO conductive layer by adopting an evaporation process.

In particular, the amount of the solvent to be used,preparing a CuPc hole transport layer on the ITO conductive layer by adopting an evaporation process, wherein the pressure in the whole process is less than 9 × 10^-4The preparation of the CuPc hole transport layer is carried out in a high vacuum chamber of Pa, and the evaporation rate adopted for preparing the CuPc hole transport layer is controlled inThe thickness of the CuPc layer is controlled to be 6-10 nm.

Step three, preparing CsPbBr on the hole transport layer by using a continuous evaporation process₃A perovskite thin film.

Specifically, CsPbBr is prepared on the CuPc hole transport layer through a continuous evaporation process₃Perovskite thin film, which is formed by continuous evaporation of PbBr₂The precursor layer and the CsBr precursor layer are prepared, and the whole preparation process is carried out at the pressure of less than 9 × 10^-4Pa in a high vacuum chamber.

In this embodiment, first, PbBr with a thickness of 150 to 200nm is deposited on the CuPc hole transport layer by evaporation₂The precursor layer is evaporated with 115-150 nm thick CsBr precursor layer, and CsPbBr is subjected to fine adjustment of the thicknesses of the CsBr layer and the CsBr layer₃Precise control of the composition of perovskite thin films, wherein PbBr₂The evaporation rates of the layer and the CsBr layer are controlled inFinally, CsPbBr is treated in air at 250-270 DEG C₃Annealing the perovskite film for 7-10min to promote the full crystallization of the film.

Step four, adopting an evaporation process to CsPbBr₃Depositing a modifying layer on the perovskite film to CsPbBr₃And passivating the perovskite thin film defects.

Specifically, in the CsPbBr₃Preparing MoO on the layer by adopting evaporation process_xModifying layer, the whole process is carried out under the pressure of less than 9 × 10^-4In a high-vacuum chamber of Pa, MoO_xThe evaporation rate is controlled in MoO_xThe thickness of the layer is controlled to be 4-8 nm.

And fifthly, depositing an Ag electrode layer on the modification layer by adopting an evaporation process, thereby completing the preparation of the photoelectric detector.

In particular, in said MoO_xPreparing an Ag electrode layer on the modification layer by an evaporation process, and controlling the evaporation rateThe thickness of the Ag electrode layer is controlled to be 110-120 nm, and the pressure intensity is less than 9 × 10 in the whole preparation process^-4Pa in a high vacuum chamber.

The present invention is further described in detail below with reference to several specific examples.