Novel low-dimensional organic-inorganic hybrid metal halide

Abstract

The invention discloses a novel low-dimensional organic-inorganic hybrid metal halide, and relates to the technical field of novel materials, the molecular formula of the low-dimensional organic-inorganic hybrid metal halide is [EMPA] 2Pb3Br12, EMPA is protonated 5-[(4-ethyl piperazine-1-yl) methyl] pyridine-2-amine, the [EMPA] 2Pb3Br12 has bright broadband WLE, and the molecular formula of the low-dimensional organic-inorganic hybrid metal halide is as shown in the specification. And the CRI value is 91.4. The novel low-dimensional organic-inorganic hybrid metal halide [EMPA] 2Pb3Br12 provided by the invention has efficient white light emitting performance, CRI is as high as 91.4, and the novel low-dimensional organic-inorganic hybrid metal halide [EMPA] 2Pb3Br12 can pave a way for further designing and developing materials capable of effectively emitting white light for solid-state lighting application.

Description

Technical Field

[0001] The invention relates to the technical field of novel materials, and more specifically, to a novel low-dimensional organic-inorganic hybrid metal halide. Background Art

[0002] In recent years, efficient light-emitting diodes (LEDs) have become increasingly important due to their high energy efficiency and low negative impact on the environment. Particularly relevant are white light-emitting diodes (WLEDs), which are rapidly replacing traditional incandescent and fluorescent light sources. Commercial WLEDs are usually manufactured by coating blue or UV chips with mixed-component phosphors. However, they exhibit several disadvantages, such as self-absorption, low efficiency, and color instability. Single-component white-light emitting materials can overcome these disadvantages and have high color rendering index (CRI) and economical manufacturing processes in addition to better spectral stability. Organic-inorganic hybrid metal halide perovskites have broad application prospects in the fields of lasers, light-emitting diodes, solar cells, and photodetectors due to their excellent physical properties. By selecting appropriate organic ammonium ions, the structural dimensions of the inorganic frameworks based on these hybrid perovskites can be easily adjusted from one to three dimensions, thereby changing their optical and electrical properties. The development of high-quality single-component white-light emitting materials is of great significance because of their broad application prospects in display devices and solid-state lighting.

[0003] Hybrid lead halide semiconductors have attracted much attention for their applications in optoelectronic devices such as sensors, lasers, photovoltaic cells, and LEDs. Hybrid lead halide perovskites with different size structures have been widely studied for their photoluminescence properties. They have ultra-high color rendering index values, large photoluminescence quantum efficiencies (PLQEs), and stable luminescence colors. Low-dimensional hybrid lead halide semiconductor compounds with broadband white light emission (WLE) generally have excellent physical flexibility and good optical properties compared to other size-hybridized halide compounds. Achieving white light emission has been considered a key step for SSL to become a more efficient lighting source than traditional light sources.

[0004] Generally speaking, the performance of white light emission depends on two key parameters, the International Commission on Illumination (CIE) chromaticity coordinates and the color rendering index (CRI). CIE chromaticity coordinates represent the exact color of light emitted as perceived by the human eye. The standard CIE1931 chromaticity coordinates of white light are (0.33, 0.33). CRI describes the ability of a light source to render colors as ideal colors, and ranges from 0 to 100. A CRI of 80 is required for human eye-friendly applications, while an extremely high CRI of >90 is required for color-critical lighting applications such as museum exhibitions, surgery, and movies.

[0005] However, white light emission with ultrahigh color rendering index has long been limited to multi-component systems. Due to the strict manufacturing and very high cost, designing a new single-component white light with excellent color rendering properties is crucial in superoptical lasers; therefore, the present invention aims to provide a new low-dimensional organic-inorganic hybrid metal halide to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a novel low-dimensional organic-inorganic hybrid metal halide. The present invention provides a novel low-dimensional organic-inorganic hybrid metal halide EMPA] 2 Pb 3 Br 12 , has efficient white light emitting performance with a CRI of up to 91.4, which can pave the way for further design and development of materials that efficiently emit white light for solid-state lighting applications.

[0007] The above technical objectives of the present invention are achieved through the following technical solutions: a novel low-dimensional organic-inorganic hybrid metal halide, the molecular formula of which is [EMPA] 2 Pb 3 Br 12 , the EMPA is protonated 5-[(4-ethylpiperazin-1-yl)methyl]pyridin-2-amine).

[0008] The present invention is further configured as follows: the [EMPA] 2 Pb 3 Br 12 Features bright broadband WLE with a CRI value of 91.4.

[0009] The present invention also provides an application of low-dimensional organic-inorganic hybrid metal halide in super-optical laser.

[0010] In summary, the present invention has the following beneficial effects:

[0011] The present invention provides a novel low-dimensional organic-inorganic hybrid metal halide EMPA] 2 Pb 3 Br 12 , has efficient white light emitting performance with a CRI of up to 91.4, which can pave the way for further design and development of materials that efficiently emit white light for solid-state lighting applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a comparison chart of the theoretical PXRD and the experimental PXRD simulated from the structure in the embodiment of the present invention;

[0013] Figure 2is a diagram of metal halide under a fluorescent lamp and under an ultraviolet lamp in an embodiment of the present invention;

[0014] Figure 3 is the excitation spectrum of the metal halide under ultraviolet light in the embodiment of the present invention;

[0015] Figure 4 is the emission spectrum of the metal halide excited under ultraviolet light in the embodiment of the present invention;

[0016] Figure 5 is a color coordinate diagram of the emission spectrum of the metal halide excited at room temperature under ultraviolet light in an embodiment of the present invention;

[0017] Figure 6 is an emission spectrum of the small-sized metal halide crystals and the powder after grinding of the small-sized crystals in the embodiment of the present invention excited at room temperature;

[0018] Figure 7 is a graph of the life span of metal halides at different temperatures in an embodiment of the present invention;

[0019] Figure 8 It is a comparison diagram of the white light LED made of metal halide in the embodiment of the present invention before and after power is turned on. DETAILED DESCRIPTION

[0020] The following is combined with Figure 1-8 The present invention is described in further detail.

[0021] Example: A novel low-dimensional organic-inorganic hybrid metal halide

[0022] The molecular formula of the low-dimensional organic-inorganic hybrid metal halide in this embodiment is EMPA]2Pb3Br12 (EMPA is protonated 5-[(4-ethylpiperazine-1-yl)methyl]pyridin-2-amine). In this embodiment, a new low-dimensional structure hybrid halide [EMPA]2Pb3Br12 is simply synthesized and prepared by using EMPA as a matching organic cation, such as Figure 1 As shown in Figure 2, the correctness of the molecular structure formula was verified by structural theoretical PXRD and experimental PXRD. Photoluminescence measurements showed that WLE originated from self-trapped excitons, among which [EMPA]2Pb3Br12 exhibited bright broadband WLE with a CRI value of 91.4.

[0023] When exposed to ultraviolet light at a wavelength of 365 nm, crystals of [EMPA]2Pb3Br12 showed bright white light visible to the naked eye ( Figure 2 ). According to the fluorescence spectrometer test, its emission spectrum was tested in the range of 250–400nm, and the maximum excitation wavelength was 362nm ( Figure 3). When excited at 362 nm, crystals of [EMPA]2Pb3Br12 show broad white light emission, exhibiting broadband emission covering the entire visible spectrum, with a maximum peak at 463 nm at room temperature ( Figure 4 ).

[0024] The CIE color coordinates of [EMPA]2Pb3Br12 (0.32, 0.34) are very close to the CIE coordinates of ideal white light emission (0.33, 0.33), such as Figure 5 In addition, the CRI of [EMPA]2Pb3Br12 (91.4) is much higher than that of typical fluorescent light sources (≈65), and is comparable to some other 2D hybrid light sources and some rare earth-doped inorganic phosphors, meeting the requirements of most color-critical high-end applications. Moreover, the color temperature of 7109K corresponds to "cold" white light. [ EMPA ]2 Pb 3 Br 12 The crystal was continuously exposed to strong ultraviolet light (300 W cm -2 ) for 100 hours, the PL emission spectrum of the UV-irradiated sample still matches well with the PL emission spectrum of the synthesized sample.

[0025] To confirm [EMPA] 2 Pb 3 Br 12 The inherent luminescence of the nanostructured crystals eliminates the possibility of defect emission. This example records the luminescence spectra of bulk crystals with a diameter greater than 200 μm and microscale crystal powders with a diameter less than 10 μm. Figure 6 As shown, the emission spectrum of the microscale crystalline powder is similar to that of the bulk crystal, with only slightly lower intensity, indicating the absence of surface defect emission. In general, photogenerated free carriers initially form free excitons (FEs) and then relax into twisted self-trapped excitons (STEs) due to electron-phonon coupling. However, STEs can also be thermally trapped to form FEs. At low temperatures, the thermal energy is not sufficient to release carriers from the STE state to the FE state, thereby increasing the broadband emission intensity. The coexistence of FEs and STEs can be described by a configurational coordinate diagram, and the narrow-band and broadband emission behaviors reveal [EMPA] 2 Pb 3 Br 12The important role of STEs (within the distorted lattice) in the generation of WLE. Photogenerated carriers can self-trapped in excited states, resulting in broadband emission due to the strong electron-phonon coupling in the distorted lattice. In addition, the broadband emission at ~410nm greatly increased with decreasing temperature, which means that the transport of carriers from FE to STE states is also blocked. Low temperature blocks the energy release between STE and FE states, resulting in increased emission at both ~410nm and ~530nm, which is consistent with the mechanism. In addition, at an excitation wavelength of 362nm, [EMPA] 2 Pb 3 Br 12 The room temperature PL decay curve is fitted, and the lifetime τ value at 463nm is 0.25ms. Figure 7 ).

[0026] At the same time, we fabricated a UV light-emitting diode (LED) lamp to further confirm the white light emission of 1. Figure 8 As shown, a thin layer of supersaturated solution [EMPA] 2 Pb 3 Br 12 Coated on LED lamps. After irradiation, it emits bright white light, showing great potential in device applications. In order to further study [EMPA] 2 Pb 3 Br 12 To investigate the intrinsic mechanism of photoluminescence, we performed temperature-dependent photoluminescence experiments. In general, the broad emission spectrum tends to become stronger and narrower with decreasing temperature, which is associated with the enhancement of electron-phonon coupling interactions in the distorted lattice, which has been strongly confirmed in previously reported two-dimensional layered hybrid perovskites.

[0027] In summary, a new type of low-dimensional organic-inorganic hybrid metal halide EMPA was developed. 2 Pb 3 Br 12 , with efficient white light emitting performance and a CRI as high as 91.4. The findings of this study are expected to pave the way for further design and development of materials that efficiently emit white light for solid-state lighting applications.

[0028] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A novel low-dimensional organic-inorganic hybrid metal halide, characterized by: The molecular formula of the low-dimensional organic-inorganic hybrid metal halide is [EMPA]2Pb3Br 12 , the EMPA is protonated 5-[(4-ethylpiperazin-1-yl)methyl]pyridin-2-amine).

2. A novel low-dimensional organic-inorganic hybrid metal halide according to claim 1, characterized in that: [EMPA]2Pb3Br 12 Features bright broadband WLE with a CRI value of 91.

4.

3. Use of the low-dimensional organic-inorganic hybrid metal halide according to claim 1 in superoptical lasers.

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