阅读说明：本技术 卤代荧光素弱光上转换体系及其制备方法与应用 (Halogenated fluorescein weak light up-conversion system and preparation method and application thereof ) 是由 王筱梅 于雪 王凯 叶常青 梁作芹 陈硕然 于 2020-07-01 设计创作，主要内容包括：本发明公开了卤代荧光素弱光上转换体系及其制备方法与应用,将卤代荧光素溶液与湮灭剂溶液在醇溶剂中混合,除氧,得到卤代荧光素弱光上转换体系；将卤代荧光素在溶剂中溶解,得到卤代荧光素单光子吸收上转换体系。由本发明提供的弱光上转换单组份体系可获得红-转-黄上转换发光；本发明提供的弱光上转换双组份体系不但可获得绿-转-蓝发光,还可获得白色的上转换发光,在照明领域、太阳能利用和生物医院等领域具有潜在的应用价值。(The invention discloses a halogenated fluorescein weak light up-conversion system and a preparation method and application thereof, wherein halogenated fluorescein solution and annihilator solution are mixed in alcohol solvent, and oxygen is removed to obtain the halogenated fluorescein weak light up-conversion system; dissolving halogenated fluorescein in a solvent to obtain a halogenated fluorescein single-photon absorption up-conversion system. The weak light up-conversion single-component system provided by the invention can obtain red-to-yellow up-conversion luminescence; the weak light up-conversion two-component system provided by the invention can obtain green-to-blue luminescence and white up-conversion luminescence, and has potential application value in the fields of illumination, solar energy utilization, biological hospitals and the like.)

1. The weak light upconversion system of the halogenated fluorescein is characterized by comprising the halogenated fluorescein and an annihilation agent.

2. The weak light upconversion system of halofluorescein of claim 1, wherein the annihilator is an anthracene material; the chemical structural formula of the halogenated fluorescein is as follows:

。

3. the weak light upconversion system of halofluorescein according to claim 1, wherein the molar ratio of the halofluorescein to the annihilator is 1: 20-140.

4. The halofluorescein weak light upconversion system of claim 1, wherein the halofluorescein weak light upconversion system further comprises an alcohol solvent.

5. The weak light upconversion system of halofluorescein according to claim 1, wherein the upconversion system has an excitation light wavelength of 532nm and an excitation light intensity of 5-500 mW/cm²。

6. The halogenated fluorescein single-photon absorption up-conversion system is characterized by consisting of halogenated fluorescein and a solvent.

7. The halofluorescein single-photon absorption up-conversion system of claim 6, wherein the wavelength of the excitation light of the up-conversion system is 655nm, and the intensity of the excitation light is 200-2000 mW/cm²。

8. The application of the halogenated fluorescein as a photosensitizer in a two-component weak light up-conversion system or a single photon absorption up-conversion system.

9. Use of the halofluorescein weak light up-conversion system as claimed in claim 1 for the preparation of white light-emitting materials.

10. The method for preparing the halogenated fluorescein weak light up-conversion system as described in claim 1, wherein the halogenated fluorescein and the annihilating agent are mixed in a solvent to remove oxygen, thereby obtaining the halogenated fluorescein weak light up-conversion system.

Technical Field

The invention belongs to a weak light upconversion technology, and relates to two organic weak light upconversion systems, in particular to a halogenated fluorescein weak light upconversion system, a preparation method and application thereof.

Background

Up-conversion means that light of a short wavelength (light of high energy) is obtained under excitation by light of a long wavelength (light of low energy). There are currently three classes of upconversion based on organic materials: strong two-photon absorption up-conversion (TPA-UC), triplet-triplet annihilation up-conversion (TTA-UC), and single-photon absorption up-conversion (OPA-UC). TPA-UC requires intense light at megawatts per square centimeter>MW×cm^-2) Excitation, so called strong light up-conversion, TTA-UC and OPA-UC require weak light in milliwatt/square centimeter (-mW × cm)^-2) Obtained under excitation, and is called weak light up-conversion. Obviously, the weak light up-conversion has greater application value in the fields of solar photovoltaic, photocatalysis, biomedicine, light control illumination, environmental detection and the like. At present, there are two types of organic weak light up-conversion: TTA-UC and OPA-UC. Due to their different micro-mechanisms, the materials involved are also different. The TTA-UC material is a two-component system, while the OPA-UC material is a single-component system. TTA-UC requires the co-participation of a sensitizer-annihilator two components (the medium is usually a solvent). The microscopic mechanism is as follows: the sensitizer first harvests low energy excitation light, and thus intersystem crossing (ISC); the sensitizer then transfers triplet energy to the annihilator; the last two excited triplet annihilator molecules undergo an electron spin conversion process, emitting high-energy photons that are upconverted relative to low-energy excitation light. On the other hand, OPA-UC only relates to the luminescent agent (i.e. single component) and has the mechanism that: the luminescent agent molecules have tropical absorption properties: i.e., a transition from a higher vibrational level (tropical) (St) of the ground state (S0) to an excited singlet state (S1), followed by emission of a photon of higher energy than the absorbed photon. At present, materials for strong two-photon absorption up-conversion (TPA-UC) and triplet-triplet annihilation up-conversion (TTA-UC) are reported more, while materials for single-photon absorption up-conversion (OPA-UC) are reported less, because absorption of molecules mostly transitions from zero vibrational level of the ground state to the excited state, and the phenomenon that molecules transition from higher vibrational level of the ground state to the excited state is less. In the TTA-UC system, the most reported triplet sensitizers are noble metal-containing complexes, such as noble metal porphyrins and noble metal phthalocyanines. However, the sensitizer containing noble metal complex has high preparation cost and high price, which limits the practical application.

Disclosure of Invention

The invention discloses bromo-fluorescein or iodo-fluorescein with dual-function performance. Can be used as a sensitizer of TTA-UC system and a luminescent agent of OPA-UC. Respectively triplet-triplet annihilation up-conversion (TTA-UC) and single-photon absorption up-conversion (OPA-UC). In particular to a halogen (bromine/iodine) fluorescein which has the multifunctional characteristics: namely, the compound has strong triplet state sensitization capability and can be used as a sensitizer of a TTA-UC system; meanwhile, the fluorescent powder has the absorption capacity of a tropical zone (namely, a ground state is higher in vibration energy level), and can be used as a luminescent agent of an OPA-UC system.

When the fluorescent dye is used as a sensitizer of a TTA-UC system, under the excitation of a green light (532 nm) semiconductor laser, the halogenated fluorescein can sensitize 9, 10-diphenylanthracene and derivatives thereof, the obtained upconversion fluorescence peak position is 430 nm, and the highest upconversion efficiency of the green-to-blue upconversion fluorescence peak position is 15.9%. Because the blue light has high up-conversion efficiency and has the same intensity with the yellow fluorescence of the sensitizing agent, the blue light and the yellow fluorescence of the sensitizing agent can be combined to obtain a stable white light spectrum. When the fluorescent material is used as a luminescent agent of an OPA-UC system, under the excitation of a red light (655 nm) semiconductor laser, the halogenated fluorescein is transited to an excited state (S) through ground state tropical absorption (absorption of a higher vibration energy level)₁) Then emitting up-conversion fluorescence with maximum peak position blue shiftThe conversion efficiency of red-to-yellow is up to 17.8% up to 575 nm.

The weak light up-conversion single-component system provided by the invention can obtain red-to-yellow up-conversion luminescence; the weak light up-conversion two-component system provided by the invention can obtain green-to-blue luminescence and white up-conversion luminescence, and has potential application value in the fields of illumination, solar energy utilization, biological hospitals and the like.

The invention adopts the following technical scheme:

the weak light upconversion system of the halogenated fluorescein is a two-component system (named as TTA-UC system) and comprises the halogenated fluorescein and an annihilation agent; further, the paint also comprises a solvent; the halogen fluorescein is taken as a sensitizing agent, the annihilation agent is anthracene substance, such as 9, 10-diphenyl anthracene and derivatives thereof, and the solvent is alcohol solvent.

The halogenated fluorescein single-photon absorption up-conversion system is a single-component system (called an OPA-UC system) and consists of halogenated fluorescein and a solvent, wherein the halogenated fluorescein is used as a luminescent molecule, and the solvent is a DMF solvent.

The invention discloses a preparation method of the above halogenated fluorescein weak light up-conversion system, which comprises the steps of mixing halogenated fluorescein and an annihilating agent in a solvent, and deoxidizing to obtain the halogenated fluorescein weak light up-conversion system; the solvent is n-propanol; deoxidizing by using argon; preferably, the halogenated fluorescein solution and the annihilator solution are mixed in an alcohol solvent, and oxygen is removed to obtain the halogenated fluorescein weak light upconversion system.

The invention discloses a preparation method of the halogenated fluorescein single-photon absorption up-conversion system, which comprises the steps of dissolving halogenated fluorescein in a solvent to obtain the halogenated fluorescein single-photon absorption up-conversion system; the solvent is DMF.

In the invention, a TTA-UC system and an OPA-UC system are respectively put into a cuvette and are irradiated by different exciting lights to obtain respective up-conversion spectrums. The excitation light is taken as a light source by a conventional semiconductor laser, wherein the wavelength of the excitation light of the TTA-UC system is 532nm, and the intensity of the excitation light is 5-500 mW/cm²(ii) a The excitation light wavelength of the OPA-UC system is 655nm, and the excitation light intensity is 200-2000 mW/cm²。

In the invention, the chemical structural formula of the halogenated fluorescein is as follows:

the chemical structural formula of the annihilator is as follows:

the alcohol solvent is n-propanol.

In the weak light up-conversion system of the halogenated fluorescein, the molar ratio of the halogenated fluorescein to the annihilator is 1: 20-140.

Under the excitation of a 655nm semiconductor laser, halogenated fluorescein (iodo-fluorescein or bromo-fluorescein) DMF solution can emit OPA-up-conversion yellow light; under the excitation of 532nm semiconductor laser, annihilating agent (DPA orp-DHMPA) and a sensitizer halofluorescein (iodofluorescein or bromofluorescein) in n-propanol solution can emit TTA-up-converted blue light; in addition, in iodofluorescein/DPA orp-In a DHMPA two-component system, white upconversion luminescence can also be obtained by mixing upconversion blue light with downconversion yellow light of iodofluorescein.

The invention discloses a novel halogenated fluorescein sensitizer, which comprises bromine-containing fluorescein and iodine-containing fluorescein, and is compounded with luminescent agent molecules (DPA and p-DHMPA) to generate green-to-blue TTA-UC up-conversion. Meanwhile, the two halogen fluoresceins can be used as chromophores of OPA-UC, under the excitation of a laser with lower power of 655nm, the red-to-yellow OPA-UC up-conversion can be carried out without deoxidization, the fluorescein without the halogen does not have the OPA-UC phenomenon, the slope of the logarithmic graph of the up-conversion integral to the power density is 1, and the effect of a single photon is shown. (ii) a The two chromophores are applied to photocurrent, and under the illumination of a red-to-yellow up-conversion system, the silicon cell photodiode generates obvious photocurrent (I-V curve), so that the potential application value of the red-to-yellow OPA up-conversion system as an excitation light source to excite the solar cell is proved.

Drawings

FIG. 1 shows the absorption and fluorescence spectra of bromofluorescein and iodofluorescein (n-propanol, 10 μ M);

FIG. 2 fluorescence decay curves and fitted lifetimes (n-propanol, 10 μ M) for bromofluorescein and iodofluorescein;

FIG. 3 phosphorescence spectra and phosphorescence lifetime curves (n-propanol, 10 μ M) for bromofluorescein (a) and iodofluorescein (b) at 77K;

FIG. 4 annihilator DPA (a) andp-absorption and fluorescence spectra of dhmpa (b) (n-propanol, 50 μ M);

FIG. 5 is a plot of the upconversion intensity versus excitation light power density at 532nm excitation for iodofluorescein/DPA and bromofluorescein/DPA (left) and the corresponding logarithm of the upconversion integral versus logarithm of the power density (right) (degassed n-propanol with sensitizer concentration set at 10 μ M);

FIG. 6 shows iodofluorescein @underexcitation at 532nmp-DHMP (a) and bromofluoresceinp-Dhmpa (b) the relationship between upconversion intensity and excitation light power density and the corresponding logarithm of integration of upconversion versus logarithm of power density (degassed n-propanol, sensitizer concentration 10 μ M);

FIG. 7 relationship between the conversion intensity on iodofluorescein/DPA and bromofluorescein/DPA and the concentration of annihilator under excitation at 532nm (degassed n-propanol, fixed sensitizer concentration at 10 μ M);

FIG. 8 Iofluorofluorescein @, under excitation at 532nmp-DHMPA and bromofluorescein-p-Relationship between DHMPA up-conversion intensity and annihilator concentration (n-propanol degassed, fixed sensitizer concentration at 10 μ M);

FIG. 9 four binary systems (iodofluorescein @)p-DHMPA, bromofluorescein-p-DHMPA, iodofluorescein/DPA and bromofluorescein/DPA) as a function of the concentration of the annihilating agent;

FIG. 10 is a plot of single photon absorption upconversion spectra of iodofluorescein (a) and bromofluorescein (b) and the corresponding integrated logarithm of upconversion versus the logarithm of power density under 655nm excitation (DMF solvent, concentration of annihilator 0.2 mM);

FIG. 11 is a spectrum of upconversion spectra (DMF, 1 mM) in fluorescein, iodofluorescein, and bromofluorescein concentrations under 655nm excitation;

FIG. 12 shows the ratios of bromine-containing fluorescein and iodine-containing fluorescein at 2 × 10^-4A photoelectric conversion diagram of up-converted light in a solution with a concentration of mol/L and under the excitation of a 655nm laser;

FIG. 13 is a nuclear magnetic spectrum of iodofluorescein;

FIG. 14 is a mass spectrum of iodofluorescein;

FIG. 15 is a nuclear magnetic spectrum of bromofluorescein;

FIG. 16 is a mass spectrum of bromofluorescein.

Detailed Description

The invention is further described with reference to the following figures and examples:

in this example, the measurement of the UV-vis absorption spectrum was performed on a SHIMADZU UV2600 type UV spectrophotometer; the fluorescence spectra were measured on an Edinburgh FLS-920 type fluorescence spectrometer, respectively. The determination conditions of the triplet-triplet annihilation up-conversion (TTA-UC) spectrum are: the solvent was spectroscopically pure degassed n-propanol using a 532nm semiconductor laser. The measurement conditions for single photon absorption up-conversion (OPA-UC) spectra were: the solvent was spectrally pure DMF using a 655nm semiconductor laser.

The halogenated fluorescein weak light up-conversion system consists of halogenated fluorescein, an annihilator and a solvent, and specifically, a halogenated fluorescein solution and an annihilator solution are mixed in an alcohol solvent, and oxygen is removed without adding other components to obtain the halogenated fluorescein weak light up-conversion system.