A hybrid based on perovskite nanocrystals and near-infrared dye molecules, as well as its preparation method and application

Abstract

The present invention discloses a hybrid based on perovskite nanocrystal-near-infrared dye molecules, a preparation method thereof, and an application thereof. The hybrid comprises perovskite nanocrystals and near-infrared dyes; wherein the perovskite nanocrystals are CsPbI3 NCs; the near-infrared dye has a general structural formula as shown in Formula I; the Pb on the surface of the perovskite nanocrystals is 2+ The hybrid is anchored and coordinated to at least one R1 group on the near-infrared dye via electrostatic forces. This hybrid exhibits a dual-mode excitation mechanism, significantly improving light-harvesting efficiency compared to single perovskite nanocrystals or single near-infrared dye molecules, breaking through the efficiency bottleneck of traditional single pathways. It also boasts a broad absorption spectrum response from 300 to 900 nm, improving photostability and dispersibility, and laying the material foundation for practical applications in photodynamic therapy, upconversion luminescence, and photocatalysis. #imgabs0#I

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials, and specifically comprises a hybrid based on perovskite nanocrystals and near-infrared dye molecules, and a preparation method and application thereof. Background Art

[0002] In recent years, inorganic semiconductor nanocrystals (NCs) and quantum dots (QDs) have shown significant potential for applications in photovoltaics, light-emitting diodes, and photodetectors due to their exceptional optoelectronic properties, such as high absorption cross sections and size-tunable optical band gaps. To further expand these functionalities, hybridization of organic molecules with inorganic NCs / QDs has become a research hotspot. These hybrid systems combine the electronic properties of inorganic materials with the chemical activity of organic molecules, enabling efficient utilization of excitons through excited-state energy or charge transfer, such as singlet / triplet energy transfer (SET / TET) or electron / hole transfer. The generation of triplet excitons is particularly critical, playing a central role in applications such as photodynamic therapy, photon upconversion, and photocatalysis.

[0003] However, existing hybrid systems still face multiple challenges. First, the efficiency of exciton or charge transfer is limited by the coupling strength and energy level matching of the organic-inorganic interface. Traditional hybrid strategies usually rely on groups such as carboxylic acid to anchor molecules to shorten the interface distance, but if the energy level arrangement (ELA) of the inorganic material and the molecule does not match, the charge separation state is difficult to effectively recombine into a triplet state. Secondly, there is a competitive relationship between excited state processes (such as SET and TET), and the excited state path needs to be regulated through sophisticated energy band design. In addition, the light response range of existing systems is narrow and it is difficult to cover the ultraviolet to near-infrared spectral region, which limits the efficiency of light energy utilization. For example, most hybrid systems rely only on a single excitation mode (such as directly excited molecules or NCs), resulting in insufficient photon capture ability, and the efficiency of triplet generation is limited by slow spin flip rates or complex intermediate state dynamics. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the first object of the present invention is to provide a hybrid based on perovskite nanocrystals and near-infrared dye molecules.

[0005] The second object of the present invention is to provide a method for preparing the hybrid as described above.

[0006] The third object of the present invention is to provide an application of the hybrid based on perovskite nanocrystals and near-infrared dye molecules as described above in the preparation of solar cells, upconversion luminescent materials, and photodynamic therapy products.

[0007] To achieve the above first object, the technical solution adopted by the present invention includes:

[0008] The present invention discloses a hybrid based on perovskite nanocrystals and near-infrared dye molecules, wherein the hybrid comprises perovskite nanocrystals and near-infrared dyes;

[0009] Wherein, the perovskite nanocrystals are CsPbI3NCs, abbreviated as NCs;

[0010] The general structural formula of the near-infrared dye is shown in Formula I:

[0011] I;

[0012] In Formula I,

[0013] R1 is selected from methyl, One of the following, and the two R1s are not methyl at the same time, "." represents the position where R1 is connected to N on the parent nucleus;

[0014] The value of n is an integer from 0 to 6;

[0015] X is selected from any one of H, Br, Cl, and an alkyl group having 1 to 4 carbon atoms;

[0016] Y is selected from any one of H, an alkyl group having 1 to 10 carbon atoms, and a cycloalkyl group having 3 to 10 carbon atoms;

[0017] R2 is selected from any one of H, Br, Cl, and I;

[0018] The Pb on the surface of the perovskite nanocrystal 2+ It is anchored and coordinated with at least one R1 group on the near-infrared dye through electrostatic force to form a stable interface. Technicians can understand that anchoring and coordination can only occur when R1 is not selected from methyl. Therefore, it is necessary to satisfy that the two R1s are not methyl at the same time.

[0019] In the present invention, based on the special energy level arrangement of perovskite nanocrystals and near-infrared dyes, the ultrafast electron spin flip rate of perovskite nanocrystals, and the characteristics of near-infrared dye molecules (i.e., the molecular structure and absorption spectrum), the special excited state behavior and efficient triplet state generation of the hybrid system are maintained. The special excited-state behavior of the hybrid system can be specifically divided into two cases, namely, occurring under the conditions of selective excitation of near-infrared dye molecules and perovskite nanocrystals, respectively, and having a dual-mode excitation mechanism. When near-infrared light selectively excites near-infrared dye molecules, the electrons on the LUMO of the near-infrared dye molecules undergo electron transfer (ElecT) and are injected into the perovskite nanocrystal to form a charge-separated state (CT). Subsequently, the charge-separated state undergoes charge recombination (CR) to produce a triplet state. This process ultimately manifests as ElecT-mediated intersystem crossing (ISC), which is achieved with the help of the energy level arrangement of the hybrid and the electron spin flip rate of the perovskite nanocrystal. When visible light selectively excites the perovskite nanocrystal, the excitons undergo a one-step TET to produce a triplet state instead of ElecT. This is a novel phenomenon in the triplet-sensitized system of perovskite nanocrystal-near-infrared dye molecule hybrid. Based on the above-mentioned dual-mode excitation mechanism, the hybrid system can achieve a wide absorption spectrum response in the range of 300-900 nm. The light capture efficiency is greatly improved compared to single perovskite nanocrystals and near-infrared dye molecules, while also improving the photostability and dispersibility.

[0020] In terms of molecular structure, at least one R1 on the near-infrared dye molecule has one of the following groups: carboxyl, sulfate, amino, thiol, or diethyl phosphite, which can enable anchoring of the near-infrared dye and the surface of the perovskite nanocrystal; in addition, the six-membered ring structure connected to R2 in the near-infrared dye molecule can reduce the rapid non-radiative transition of the excited state caused by the torsion of the entire compound. This structure can provide a longer excited state lifetime for subsequent excited state behavior.

[0021] In terms of absorption spectrum, near-infrared dye molecules have a near-infrared absorption band. This feature has the following three effects. First, it can meet the needs of near-infrared light excitation, which enables nanocrystals that originally cannot absorb near-infrared light to absorb near-infrared light; second, this means that the excited singlet energy of the near-infrared dye molecules is lower than the first exciton absorption peak energy of the nanocrystals, avoiding the singlet energy transfer of excited-state molecules to the nanocrystals; third, the absorption spectrum of the nanocrystals and the absorption spectrum of the near-infrared dye molecules can jointly cover the wavelength range of no more than 900 nm, and further the range of 300-900 nm, which enables the hybrid to absorb all wavelengths of light in the ultraviolet, visible and near-infrared regions, greatly expanding the absorption capacity and usage environment of the hybrid.

[0022] Furthermore, the perovskite nanocrystals are prepared using a hot injection method, have a particle size of 5-13 nm, and an electron spin flip rate of 3-10 ps. The ultra-fast electron spin flip rate of the perovskite nanocrystals can cause the electrons in the CT state in the nanocrystal's conduction band to undergo charge flipping. Only when the electrons in the conduction band complete the flip can the CT state recombine to form the triplet state of the molecule; otherwise, the CT state will complete the recombination by returning to the ground state, and the triplet state of the molecule cannot be formed. In common inorganic nanocrystals or quantum dots, the electron spin flip of 2-20 nm perovskites typically occurs within 10 ps, which is a significant advantage over other materials such as CdS, CdSe, ZnS, ZnSe, and InP, which all have electron spin flips of at least 30 ps.

[0023] Furthermore, the conduction band energy level of the perovskite nanocrystal is -3.7 to -3.3 eV, and the valence band energy level of the perovskite nanocrystal is -5.7 to -5.4 eV;

[0024] The LUMO energy level of the near-infrared dye is -3.0 to -3.8 eV, and the HOMO energy level of the near-infrared dye is -4.5 to -5.5 eV.

[0025] Furthermore, the perovskite nanocrystal and the near-infrared dye satisfy at least one of the following energy level arrangement thresholds:

[0026] 1) The LUMO energy level of the near-infrared dye is 0.1-0.3 eV higher than the conduction band energy level of the perovskite nanocrystal;

[0027] 2) The HOMO energy level of the near-infrared dye is 0.2-0.9 eV higher than the valence band energy level of the perovskite nanocrystal.

[0028] This unique energy level arrangement results in the near-infrared dye molecule's LUMO and HOMO being higher than the perovskite nanocrystal's conduction band (CB) and valence band (VB), respectively, with the energy difference remaining within a predefined threshold. The near-infrared dye molecule's LUMO energy level is 0.1-0.3 eV higher than the perovskite nanocrystal's CB, ensuring electron transfer from the LUMO orbital to the CB. The HOMO energy level is 0.2-0.9 eV higher than the perovskite nanocrystal's VB, blocking hole transfer. This designed energy level arrangement provides the driving force for the aforementioned excited-state behavior while preventing other behaviors. For example, when the LUMO is lower than the CB, electron transfer from the excited molecule's LUMO orbital to the CB is unlikely, with a ΔGET greater than 0. When the HOMO is lower than the VB, the excited molecule's HOMO orbital is easily transferred to the VB, leading to hole transfer and preventing the desired excited-state behavior.

[0029] Furthermore, the mass ratio of the perovskite nanocrystals to the near-infrared dye is 1:0.1-1, for example, the mass ratio of the perovskite nanocrystals to the near-infrared dye can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1, etc.

[0030] Furthermore, the near-infrared dye is selected from one of the structures shown below:

[0031] .

[0032] Furthermore, the hybrid further comprises an organic solvent, and the organic solvent is selected from toluene or n-hexane.

[0033] Furthermore, the concentration of the hybrid is 0.01-0.8 mg / mL. Exemplarily, the concentration of the hybrid can be 0.01 mg / mL, 0.05 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, etc.

[0034] Furthermore, the particle size distribution of the hybrid is ≤20 nm.

[0035] To achieve the above second purpose, the technical solutions adopted by the present invention include:

[0036] The present invention discloses a method for preparing the hybrid as described above, comprising the following steps:

[0037] 1) Preparation of perovskite nanocrystals by hot injection

[0038] 1-1) 0.2-0.3 g Cs2CO3, 0.8-1.2 mL oleic acid, and 8-12 mL octadecene were vacuum degassed at 130-160°C for 15-30 minutes to prepare a Cs-oleic acid precursor;

[0039] 1-2) Dissolve 100-120 mg of PbI2 and 200-300 mg of ZnI2 in 3-7 mL of octadecene, 1-2 mL of oleylamine, and 1-2 mL of bis(2,4,4-trimethylpentyl)phosphonic acid (TMPPA) at 140-150 °C under nitrogen to prepare a Pb / I precursor.

[0040] 1-3) Rapidly inject 0.3-0.5 mL of Cs-oleic acid precursor into the Pb / I precursor, react at 140-150°C for 15-20 seconds, and then quench in an ice bath.

[0041] 1-4) centrifuging, washing, and dispersing the collected nanocrystal solids in an organic solvent to obtain a perovskite nanocrystal solution;

[0042] 2) Preparation of hybrids

[0043] The near-infrared dye is added to the perovskite nanocrystal solution, ultrasonicated, and centrifuged to obtain the product.

[0044] Furthermore, the centrifugation conditions in steps 1-4) are 8000-10000 rpm×10 minutes.

[0045] Furthermore, the solvent used for washing in step 1-4) is a polar solvent such as methyl acetate.

[0046] Furthermore, the concentration of the perovskite nanocrystal solution is 0.5-5 mg / mL, and the mass volume ratio of the near-infrared dye to the perovskite nanocrystal solution is 1-5 mg:1 mL.

[0047] Furthermore, the ultrasonic treatment conditions are as follows: ultrasonic power of 100-200 W, ultrasonic frequency of 40 kHz, and ultrasonic time of 20-40 minutes.

[0048] Furthermore, the purpose of centrifugation in step 2) is to remove unbound near-infrared dye, and the centrifugation condition can be 3000 rpm×5 minutes.

[0049] To achieve the third objective, the present invention employs the following technical solutions:

[0050] The present invention discloses an application of the hybrid as described above in the preparation of light-responsive materials, photodynamic diagnostic and therapeutic materials, up-conversion luminescent materials, and photovoltaic device materials.

[0051] Beneficial effects of the present invention:

[0052] The present invention proposes a new hybrid system based on perovskite nanocrystals and near-infrared dye molecules. Through unique energy band engineering and interface design, the system achieves efficient triplet generation under dual-mode excitation: (1) When near-infrared light excites the dye, electron transfer and the spin-orbit coupling of the perovskite work together to drive the charge complex state to generate a triplet state through intersystem crossing; (2) When visible light excites the perovskite nanocrystal, the exciton sensitizes the molecular triplet state through direct triplet energy transfer without an intermediate charge transfer state. The two excitation modes respectively utilize the energy level gradient and interface coupling advantages of the hybrid system, and the light capture efficiency is greatly improved compared to that of a single perovskite nanocrystal and a near-infrared dye molecule, breaking through the efficiency bottleneck of the traditional single path. In addition, the Pb on the surface of the perovskite nanocrystal 2+By anchoring the near-infrared dye with at least one R1 group through electrostatic forces, the material significantly broadens the absorption spectrum (300-900 nm) while also improving photostability and dispersibility. This innovative design not only provides new insights into light-controlled electron transfer mechanisms but also lays a material foundation for practical applications in photodynamic therapy, upconversion luminescence, and photocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The transmission electron microscopy images and size distribution of the nanocrystals and the transmission electron microscopy images of the hybrids in Example 1 are shown. Figure 1 In the figure, a is the transmission electron microscopy image of the nanocrystals, b is the size distribution of the nanocrystals, and c is the transmission electron microscopy image of the hybrid.

[0054] Figure 2 The schematic diagram of the hybrid structure, absorption spectrum, emission spectrum, and energy band structure of Example 1 are shown, wherein: Figure 2 In the figure, a is a schematic diagram of the hybrid structure, b is the absorption spectrum, c is the emission spectrum, and d is the band structure.

[0055] Figure 3 The schematic diagram of the dual-mode excitation mechanism of the hybrid of Example 1 is shown, wherein Figure 3 a is the ElecT-ISC excitation mechanism, and b is the TET excitation mechanism.

[0056] Figure 4 The excitation mechanism verification of the ElecT-ISC excitation mechanism of the hybrid of Example 1 is shown.

[0057] Figure 5 The TET excitation mechanism of the hybrid of Example 1 is shown.

[0058] Figure 6 The singlet oxygen activation experiment test diagram in Example 2 is shown.

[0059] Figure 7 The experimental test diagram of the up-conversion luminescent material in Example 7 is shown. DETAILED DESCRIPTION

[0060] In order to more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments and accompanying drawings. It should be understood by those skilled in the art that the content described below is illustrative and non-restrictive and should not be used to limit the scope of protection of the present invention. The preparation methods in the present invention are all conventional methods unless otherwise specified. The raw materials used can be obtained from public commercial sources or prepared according to the prior art unless otherwise specified.

[0061] Example 1

[0062] 1) Preparation of CsPbI3NCs, including the following steps:

[0063] (1) In a 25 mL Schlenk flask, 0.25 g Cs2CO3, 0.98 mL oleic acid (OA), and 9 mL octadecene (ODE) were mixed and degassed at 150 °C in vacuum for 15 min to prepare the Cs-oleic acid precursor.

[0064] (2) In a 50 mL Schlenk flask, 120 mg of PbI2 and 250 mg of ZnI2 were dissolved in 5 mL of ODE, 2 mL of oleylamine (OAm), and 2 mL of bis(2,4,4-trimethylpentyl)phosphonic acid (TMPPA) at 145 °C under nitrogen protection to prepare the Pb / I precursor;

[0065] (3) Rapidly inject 0.4 mL of Cs-oleic acid precursor into the Pb / I precursor, keep the reaction warm for 20 seconds, and then quench in an ice bath;

[0066] (4) The nanocrystals were collected by centrifugation (10,000 rpm × 10 min), washed three times with methyl acetate, and dispersed in toluene to obtain a nanocrystal solution with a concentration of 1 mg / mL.

[0067] Depend on Figure 1 The transmission electron microscopy characterization of a shows that the CsPbI3NCs (abbreviated as NCs) prepared by the above steps have regular morphology and uniform size. The size of CsPbI3NCs can be controlled within the size range of 7.5 ± 1.5 nm (see Figure 1 Middle b).

[0068] 2) preparing a hybrid, comprising the following steps:

[0069] 5 mg of near-infrared dye IR 808 was added to 1 mL of the nanocrystal solution prepared above, and the mixture was sonicated for 30 min (power 100 W, frequency 40 kHz), and the unbound dye was removed by centrifugation (3000 rpm×5 min). The final concentration of the hybrid was 0.8 mg / mL, and the loading amount of the near-infrared dye was determined to be 15 wt% by UV-Vis spectroscopy.

[0070] IR 808

[0071] The hybrid can be centrifuged at high speed (8000-12000 rpm×10 minutes) to obtain a separated solid phase sample, which can then be separated and diluted with toluene or n-hexane to obtain the desired concentration, such as 0.05 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, etc.

[0072] like Figure 1As shown in Figure c, the anchoring of near-infrared dye molecules in the hybrid did not cause significant changes in the size and morphology of the nanocrystals under transmission electron microscopy (TEM), and the atomic arrangement inside the nanocrystals was not affected by the molecules. This is because the near-infrared dye molecules cannot enter the interior of the nanocrystals, but only cooperate with the atoms on the interface.

[0073] Figure 2 Figure a shows a schematic structural diagram of the hybrid, where the near-infrared dye molecules are anchored to the nanocrystal surface via carboxylic acid groups.

[0074] The optical properties and excited state behaviors of the hybrid obtained in this example were characterized: Figure 2 Figure b shows the difference in absorption spectra between the nanocrystals and the hybrid. The absorption spectrum of the hybrid is extended to the 900 nm range due to the influence of the near-infrared dye molecules. Figure 2 Figure c in the middle shows that the original emission of the nanocrystals and near-infrared dye molecules in the hybrid is almost completely quenched, which means that when one component is excited, the exciton will be accepted or consumed by the other component through some energy transfer or electron transfer method; Figure 2 Figure d in the middle illustrates the energy level arrangement of nanocrystals and near-infrared dye molecules in the hybrid. The dye LUMO energy level and the perovskite conduction band form an electron transfer driving force of about 0.1-0.3 eV.

[0075] Transient absorption spectroscopy further illustrates that the hybrid obtained in this example undergoes significant changes in excited state behavior: Figure 3 The excited state behaviors of the hybrid when the near-infrared dye molecules and nanocrystals are excited separately are shown. Figure 3 In middle a), the excited electrons of the near-infrared dye molecules are transferred to the perovskite to form a charge-separated state. 1 CT, and then undergoes charge recombination to sensitize IR 808 to the triplet state, which is a new electron transfer-induced intersystem crossing mechanism; when the nanocrystal is excited (i.e. Figure 3 In figure b), the excitons do not transfer electrons or holes but instead undergo direct triplet energy transfer, which also sensitizes the near-infrared dye molecules to the triplet state.

[0076] Figure 4 The excitation mechanism of selectively exciting near-infrared dye molecules is verified by Figure 4 It can be seen from a and b that when the near-infrared dye molecules are selectively excited, the transient absorption spectrum shows a sequential change signal of the near-infrared dye molecule singlet state-charge separation state-near-infrared dye molecule triplet state.

[0077] Figure 5 The selective excitation mechanism of nanocrystals is verified by Figure 5From a to d, we know that when the nanocrystals are selectively excited, the transient absorption spectrum shows a sequential change signal of the excited nanocrystal-near-infrared dye molecule triplet state.

[0078] Example 2

[0079] This example provides a singlet oxygen activated photoresponsive material, and the specific steps are as follows:

[0080] The hybrid prepared in Example 1 (10 μM) and 1,3-diphenylisobenzofuran (DPBF) (100 μM) were dissolved in toluene and irradiated with an 808 nm laser (power density 1 W / cm 2 ) for 5 minutes, and UV-Vis spectra were recorded every 1 minute. The absorption decay of DPBF at 410 nm followed first-order kinetics. The results are shown in Figure 6 , Figure 6 Figure a illustrates the sensitization process of singlet oxygen. Figure 6 The singlet oxygen probe used in b is not directly excited by the excitation light to avoid self-bleaching. Figure 6 Figure c in the figure shows that the singlet oxygen probe is gradually oxidized as the hybrid is exposed to light for an extended period of time. Figure 6 Figure d shows that the singlet oxygen yield was quantified by the change in absorbance and was 76%.

[0081] Example 3

[0082] This example provides a singlet oxygen activated photoresponsive material, and the specific steps are as follows:

[0083] The hybrid prepared in Example 1 (10 μM) and 1,3-diphenylisobenzofuran (DPBF) (100 μM) were dissolved in toluene and illuminated with a near-infrared LED light source (power density 1 W / cm 2 ) for 5 minutes, and UV-Vis spectra were recorded every 1 minute. The absorption peak of DPBF was significantly bleached, indicating that singlet oxygen was produced with an efficiency of 74%.

[0084] Example 4

[0085] This example provides a singlet oxygen activated photoresponsive material, and the specific steps are as follows:

[0086] The hybrid prepared in Example 1 (10 μM) and 1,3-diphenylisobenzofuran (DPBF) (100 μM) were dissolved in toluene and irradiated with a near-infrared xenon lamp (power density 1 W / cm 2 ) for 5 minutes, and UV-Vis spectra were recorded every 1 minute. The absorption peak of DPBF was significantly bleached, indicating that singlet oxygen was produced with an efficiency of 77%.

[0087] Example 5

[0088] This example provides a singlet oxygen activated photoresponsive material, and the specific steps are as follows:

[0089] The hybrid prepared in Example 1 (10 μM) and 1,3-diphenylisobenzofuran (DPBF) (100 μM) were dissolved in toluene and illuminated with a white LED light source (power density 1 W / cm 2 ) for 5 minutes, and UV-Vis spectra were recorded every 1 minute. The absorption peak of DPBF was significantly bleached, indicating that singlet oxygen was produced with an efficiency of 68%.

[0090] From the results of Examples 2-5, it can be seen that the hybrid of the present invention is applicable to a variety of light sources and has wide adaptability.

[0091] Example 6

[0092] This example provides a near-infrared photodynamic therapy material. The specific steps are as follows:

[0093] The hybrid prepared in Example 1 is mixed with a hydrogel (or surfactant) to form emulsion microspheres. After being injected subcutaneously, the high penetrability of near-infrared light is utilized to directly excite near-infrared dye molecules, generating singlet oxygen for photodynamic diagnosis and therapy.

[0094] Example 7

[0095] This example provides a near-infrared light-excited triplet-triplet annihilation upconversion (TTA-UC) luminescent material. The specific steps are as follows:

[0096] In a deoxygenated atmosphere, the hybrid prepared in Example 1 and the TTA annihilator rubrene (Rub) were added to chromatographically pure toluene and mixed evenly to obtain an upconversion luminescent material, wherein the molar ratio of the hybrid to rubrene was 1:1000.

[0097] Figure 7 Figure a illustrates the upconversion luminescence process of the hybrid with rubrene molecules using the TTA strategy. Figure 7 Figure b shows that the system can obtain significant upconversion luminescence under the excitation of 808 nm laser. Figure 7 Figure c in the middle shows that the upconversion luminescence intensity gradually increases with the increase of the excitation light power density.

[0098] Example 8

[0099] This example provides a photovoltaic device material, and the specific steps are as follows:

[0100] The ITO glass was ultrasonically cleaned with acetone and then ethanol, followed by spin coating of a dense TiO2 layer (4000 rpm for 30 seconds). A mixed layer (10 mg / mL) of the hybrid from Example 1 and Rubrene (approximately 100 nm thick) was spin-coated on the ITO glass surface at a mass ratio of 1:500 to 1:5000. A 100 nm thick Ag electrode was then evaporated on the mixed layer. Experiments revealed that photocurrent was consistently obtained under AM 1.5G illumination at various raw material mass ratios.

[0101] Comparative Example 1

[0102] In this example, the following near-infrared dye molecules were used to prepare nanocrystal-near-infrared dye molecule hybrids, and the preparation method was referred to Example 1:

[0103]

[0104] This molecule differs from IR 808 in that it lacks a six-membered ring on the double-single bond carbon bridge in its central region. This missing six-membered ring reduces the rigidity of the molecule, making it more susceptible to non-radiative relaxation processes such as structural torsion in the excited state.

[0105] In transient absorption spectroscopy experiments, the excited-state lifetime of near-infrared dye molecules lacking carbon-bridged six-membered rings on their surfaces was reduced to ~370 ps. This results in the excited state of near-infrared dye molecules lacking carbon-bridged six-membered rings being less stable than that of IR 808. Consequently, the hybrid lacks sufficient time for electron transfer and subsequent photophysical processes to occur, thus failing to generate a triplet state and realize the excitation mechanism described in this invention.

[0106] Comparative Example 2

[0107] In this example, nanocrystal-alizarin molecule hybrids were prepared using alizarin molecules and cadmium sulfide nanocrystals (CdS). The preparation method was similar to that of Example 1. The energy level arrangement threshold of the hybrid of Comparative Example 2 was the same as that of the hybrid of the present invention, wherein the valence band of CdS was -5.4 eV, and the HOMO orbital of alizarin was -4.3 eV, with a difference of -0.9 eV; the conduction band of CdS was -2.5 eV, and the LUMO orbital of alizarin was -2.3 eV, with a difference of -0.2 eV.

[0108] The energy level difference of this hybrid also meets the energy level difference requirements of the present invention. However, after excitation of the alizarin molecule, the charge-separated state of Comparative Example 2 fails to undergo the expected charge recombination to generate the triplet state of the alizarin molecule, but instead returns directly to the ground state. This may be because the slow spin-flip rate of CdS (~30 ps) prevents the charge-separated state from undergoing sufficient kinetic conditions for subsequent excited-state behavior.

[0109] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A hybrid based on perovskite nanocrystals and near-infrared dye molecules, characterized in that: The hybrid comprises perovskite nanocrystals and near-infrared dyes; Wherein, the perovskite nanocrystals are CsPbI3 NCs; The general structural formula of the near-infrared dye is shown in Formula I: I； In Formula I, R1 is selected from methyl, One of the following, and the two R1s are not methyl at the same time, "." represents the position where R1 is connected to the N on the parent nucleus; The value of n is an integer from 0 to 6; X is selected from any one of H, Br, Cl, and an alkyl group having 1 to 4 carbon atoms; Y is selected from any one of H, an alkyl group having 1 to 10 carbon atoms, and a cycloalkyl group having 3 to 10 carbon atoms; R2 is selected from any one of H, Br, Cl, and I; The Pb on the surface of the perovskite nanocrystal 2+ Anchoring and coordinating with at least one R1 group on the near-infrared dye through electrostatic force; The perovskite nanocrystals are prepared by a hot injection method, have a particle size of 5-13 nm, and an electron spin flip rate of 3-10 ps.

2. The hybrid according to claim 1, characterized in that The conduction band energy level of the perovskite nanocrystal is -3.7 to -3.3 eV, and the valence band energy level of the perovskite nanocrystal is -5.7 to -5.4 eV; The LUMO energy level of the near-infrared dye is -3.0 to -3.8 eV, and the HOMO energy level of the near-infrared dye is -4.5 to -5.5 eV.

3. The hybrid according to claim 2, characterized in that The perovskite nanocrystal and the near-infrared dye satisfy at least one of the following energy level arrangement thresholds: 1) The LUMO energy level of the near-infrared dye is 0.1-0.3 eV higher than the conduction band energy level of the perovskite nanocrystal; 2) The HOMO energy level of the near-infrared dye is 0.2-0.9 eV higher than the valence band energy level of the perovskite nanocrystal.

4. The hybrid according to claim 1, characterized in that The near-infrared dye is selected from one of the following structures: 。 5. The hybrid according to claim 1, characterized in that The particle size distribution of the hybrid is ≤20 nm.

6. The hybrid according to claim 1, characterized in that The mass ratio of the perovskite nanocrystal to the near-infrared dye is 1:0.1-1.

7. The method for preparing a hybrid according to any one of claims 1 to 6, wherein: The following steps are involved: 1) Preparation of perovskite nanocrystals by hot injection 1-1) 0.2-0.3 g Cs2CO3, 0.8-1.2 mL oleic acid, and 8-12 mL octadecene were vacuum degassed at 130-160°C for 15-30 minutes to prepare a Cs-oleic acid precursor; 1-2) Dissolve 100-120 mg of PbI2 and 200-300 mg of ZnI2 in 3-7 mL of octadecene, 1-2 mL of oleylamine, and 1-2 mL of bis(2,4,4-trimethylpentyl)phosphonic acid at 140-150 °C under nitrogen to prepare a Pb / I precursor. 1-3) Rapidly inject 0.3-0.5 mL of Cs-oleic acid precursor into the Pb / I precursor, react at 140-150°C for 15-20 seconds, and then quench in an ice bath. 1-4) centrifuging, washing, and dispersing the collected nanocrystal solids in an organic solvent to obtain a perovskite nanocrystal solution; 2) Preparation of hybrids The near-infrared dye is added to the perovskite nanocrystal solution, ultrasonicated, and centrifuged to obtain the product.

8. The preparation method according to claim 7, characterized in that The concentration of the perovskite nanocrystal solution is 0.5-5 mg / mL, and the mass volume ratio of the near-infrared dye to the perovskite nanocrystal solution is 1-5 mg:1 mL.

9. Use of the hybrid based on perovskite nanocrystals and near-infrared dye molecules according to any one of claims 1 to 6 in the preparation of photoresponsive materials, photodynamic diagnostic and therapeutic materials, upconversion luminescent materials, and photovoltaic device materials.

Images