Novel organic-inorganic hybrid perovskite photoelectric material and preparation method thereof

Abstract

At present, perovskite luminescent materials mainly face the following two key problems: 1, lead-based perovskite is strong in toxicity and easy to degrade in wet oxygen; and 2. 3D crystal boundary recombination is more, the migration rate is low, and commercial and performance improvement is hindered. According to the invention, an organic molecule with intermolecular cation-pi interaction and intramolecular pi conjugation effect is selected to replace a traditional A-site inorganic element, and Bi < 3 + > is doped, so that a novel one-dimensional organic-inorganic hybrid lead-free material Bi-C12H12N2Ge2Br6 perovskite is synthesized, and a preparation method for realizing the material is provided. The material and the preparation method thereof have important significance on high response and intrinsic stability of novel lead-free perovskite.

Description

Technical Field

[0001] This invention belongs to the field of perovskite optoelectronic materials, and specifically relates to a method for preparing organic-inorganic hybrid perovskite optoelectronic materials. Background Technology

[0002] Perovskite materials (especially metal-organic inorganic perovskites) have shown great promise in the optoelectronic field due to their excellent optoelectronic properties (such as high luminous efficiency, tunable bandgap, and low-cost solution preparation). Organic-inorganic lead-based perovskites, with their four major advantages of high efficiency, low defects, tunable bandgap, and low-temperature solution processing, have become star optoelectronic platforms covering multiple scenarios including photovoltaics, LEDs, and detection. However, lead-free production and high stability are key factors for practical applications. By adopting Ge... 2+ Bi 3+ Replacing lead with environmentally friendly elements and combining this with low-dimensional (especially one-dimensional) crystal structure design to reduce defect state density has become an effective way to improve the environmental compatibility and structural stability of materials. Furthermore, introducing π-conjugated systems or intermolecular interactions (such as cation-π interactions) into organic components has been shown to simultaneously optimize the charge transport properties and intrinsic stability of materials.

[0003] Combining the aforementioned strategies of element substitution, dimensional regulation, and organic cation engineering to synergistically improve the overall performance of materials is a cutting-edge direction for promoting the development of high-performance, high-stability lead-free perovskite optoelectronic devices. Summary of the Invention

[0004] Organic-inorganic hybrid perovskites (OIHPs) exhibit unique advantages in the field of optoelectronic materials, stemming from their superior photoelectric conversion efficiency, tunable bandgap structure, and excellent carrier transport characteristics. OIHPs can simultaneously achieve high water stability and high photoelectric performance through cation-π interactions between organic components and intramolecular π-conjugation effects. This invention is the first to develop a novel organic-inorganic hybrid perovskite material, (4,4′-VDP)B₂Br₆ (B: Pb, Ge, Sn, Bi, etc.), contributing significantly to the field of optoelectronic materials.

[0005] Technical implementation elements:

[0006] To address development needs, this invention provides a novel organic-inorganic hybrid perovskite Bi-C 12 H 12 N2Ge2Br6 material and its preparation method, the method includes the following steps: synthesis of Bi-C by cooling recrystallization. 12 H 12N2Ge2Br6 crystals, weigh out 0.5 mmol GeO2 and 0.5 mmol C. 12 H 10 N2 and 0.020 mmol BiBr3 were added to a three-necked flask, followed by 15 ml HBr and 2 ml H3PO2. The mixture was heated to 120 °C under nitrogen protection and continuous magnetic stirring. After clarification, the mixture was slowly cooled to crystallize and washed with isopropanol and filtered.

[0007] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0008] Material composition and properties: Most existing perovskite optoelectronic materials are lead-based perovskite materials, which cause significant environmental pollution, have poor stability, and are difficult to further improve in terms of responsivity. In contrast, organic-inorganic hybrid perovskite photodetectors have synergistic advantages over all-inorganic perovskite devices in terms of continuously tunable bandgap, defect density suppression, extended carrier diffusion length, low-temperature compatibility with flexible substrates, and built-in polarization electric field modulation. They can simultaneously achieve broad-spectrum response, high responsivity, low dark current, and fast response speed within a single semiconductor layer, overcoming the performance bottlenecks of inorganic perovskite, such as limited bandgap adjustment, high dark current, and high flexible processing temperature.

[0009] 2) Structure: Bi-C 12 H 12 The perovskite material N2Ge2Br6 has a P-1 space group structure.

[0010] 3) Process: Based on a mixed solvent (HBr / H3PO2) cooling recrystallization technique. This invention prepares Bi-C through a one-step reaction combined with a cooling recrystallization process. 12 H 12 N2Ge2Br6 organic-inorganic hybrid perovskite optoelectronic material. Attached Figure Description

[0011] Figure 1 The fluorescence emission spectrum of perovskite materials prepared according to existing technology;

[0012] Figure 2 The XRD pattern of the synthesized material achieved according to the present invention;

[0013] Figure 3 Scanning electron microscopy (SEM) results;

[0014] Figure 4 The photocurrent and responsivity spectra of devices fabricated from perovskite optoelectronic materials synthesized according to the present invention are shown at 420 nm.

[0015] Figure 5The graph shows the external quantum efficiency and detectivity of a device fabricated from the perovskite optoelectronic material synthesized according to the present invention at 420 nm. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0017] In this invention, the organic-inorganic hybrid perovskite structure and its enhanced carrier spatial separation make it a low-cost and relatively stable optoelectronic material with development potential.

[0018] The principle of the cooling recrystallization method, which has relatively simple processing and low experimental requirements, is to completely dissolve the raw materials in a mixed solvent (HBr / H3PO2) and then cool it for crystallization. Studies have shown that Bi doping significantly improves photoelectric responsivity. More importantly, by suppressing charge recombination and promoting carrier spatial separation, a synergistic enhancement of photoelectric performance and intrinsic stability is achieved.

[0019] Example 1

[0020] An organic-inorganic hybrid perovskite material, the specific preparation steps of which are as follows:

[0021] Step 1: Clean a three-necked flask; clean the three-necked flask with deionized water, acetone, isopropanol, and deionized water for ten minutes each, then dry it with a nitrogen gun.

[0022] Step 2: First, under a nitrogen atmosphere and with constant stirring, add 0.5 mmol GeO2 and 0.5 mmol C 12 H 10 N2 and 0.020 mmol BiBr3 were dissolved in 15 ml HBr and 2 ml H3PO2;

[0023] Step 3: Stir the reaction thoroughly at 120℃;

[0024] Step 4: After slow cooling and crystallization, the liquid is removed, and the crystal is washed with isopropanol and filtered to obtain the final organic-inorganic hybrid perovskite crystal.

[0025] Technical Summary

[0026] This invention discloses a highly responsive organic-inorganic hybrid perovskite material and its universal preparation method, which includes the following steps: using HBr and H3PO2 as solvents, adding organic molecules C 12 H 10N2, GeO2, and BiBr3 were heated to 120°C under a nitrogen atmosphere and with continuous stirring. After clarification, the mixture was slowly cooled and crystallized. The resulting organic-inorganic hybrid perovskite optoelectronic material was obtained by washing with isopropanol and filtering.

[0027] The optoelectronic material realized according to the present invention has the characteristics of high responsivity and high water stability.

Claims

1. A high-response inorganic-organic hybrid perovskite material, synthesized by a cooling recrystallization method, having the chemical formula Bi-C 12 H 12 N2Ge2Br6 perovskite optoelectronic material.

2. A method of preparing high-response organic-inorganic hybrid lead-free perovskite material as claimed in claim 1.

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