A method for producing a Ba x Pb 1-x S alloy using a molecular precursor route

Abstract

The application discloses a method for preparing Ba x Pb 1‑x S alloy by using a molecular precursor route, which comprises the following steps: firstly, synthesizing barium dibutyl dithiocarbamate and lead dibutyl dithiocarbamate solids; dispersing the two kinds of solids by using carbon disulfide to obtain a mixed solution; and reacting and alloying under the condition of nitrogen to obtain Ba x Pb 1‑x S alloy powder; or dropping and coating the mixed solution on a quartz glass and reacting and alloying to obtain a Ba x Pb 1‑x S alloy thin film. The Ba 0.5 Pb 0.5 S alloy prepared by the method has a band gap width of 1.77 eV and can maintain good stability under high humidity conditions. The photoelectric detector constructed by the Ba 0.5 Pb 0.5 S alloy has an extremely low dark current and excellent photoelectric response capacity, and the band gap of the Ba x Pb 1‑x S alloy can be adjusted by adjusting the molar ratio of Ba and Pb in the Ba-Pb-S alloy.

Description

Technical Field

[0001] This invention belongs to the field of Ba-Pb-S alloy preparation technology, specifically relating to a method for preparing Ba using a molecular precursor route. x Pb 1-x Methods for S alloys. Background Technology

[0002] Multijunction tandem solar cells (TSCs) have attracted much attention due to their potential to exceed the Shockley-Queisser (SQ) limit and achieve higher power conversion efficiencies. Wide-bandgap solar cells, as a key component of TSCs, play a crucial role in capturing high-energy photons and achieving high open-circuit voltages; therefore, exploring high-performance wide-bandgap semiconductor materials is of great significance to the development of TSCs.

[0003] In recent years, in-depth research has been conducted on semiconductor materials containing lead. Studies have shown that the uniqueness of lead in semiconductor applications is inseparable from its atomic structure. The antibonding hybridization between Pb 6s and the anion p affects the upper valence band. The presence of this antibonding characteristic in the valence band will increase dispersion and hole mobility, making it widely used in semiconductor materials. For example, chalcogenide lead compounds and lead halide perovskites have high application potential as light absorption layers for solar cells and photodetectors. Researchers have begun exploring the synthesis of novel multi-component lead-based chalcogenide compounds. Kristopher M (KMKoskela, BCMelot, RLBrutchey, Solution Deposition of a Bournonite CuPbSbS3 Semiconductor Thin Film from the Dissolution of Bulk Materials with a Thiol-Amine Solvent Mixture. Journal of the American Chemical Society 2020, 142, 6173-6179.) synthesized CuPbSbS3 films with excellent properties by dissolving bulk materials using a thiol-amine solvent mixture, which can serve as an important component of solar cell absorbers.

[0004] Ba-Pb-S ternary alloys have been extensively studied as a potential novel semiconductor material, with predictions indicating their tunable bandgap, high absorption coefficient, low effective mass, and good stability, suggesting broad application prospects in thermoelectric materials and solar cells. Chattopadhyaya S (Chattopadhyaya, R. Bhattacharjee, Theoretical study of structural, electronic and optical properties of BaxPb1-xS, BaxPb1-xSe and BaxPb1-xTe ternary alloys using FP-LAPW approach. Journal of Alloys and Compounds 2017, 694, 1348-1364.) used density functional theory (DFT) to simulate the physical properties of Pb-Ba-S, calculating its band structure, bandgap, and spectrum, demonstrating that this material could be an effective candidate for optoelectronic devices. Furthermore, Li (Y.Li,L.Wang,Y.Qiao,Y.Gan,DJSingh, Prediction of ternary alkaline-earth metal Sn(II) and Pb(II)chalcogenide semiconductors. Physical Review Materials 2020,4,055004.) predicted that the band gap of Ba-Pb-S chalcogenides is approximately 1.85 eV, with strong visible light absorption and relatively low effective mass of holes and electrons. However, despite extensive theoretical research, no Ba-Pb-S ternary alloy synthesis technology has been developed or publicly disclosed. Based on the predicted superior physical properties of Ba-Pb-S ternary alloys and their potential important role in optoelectronics, there is an urgent need to develop a technical solution for preparing Ba-Pb-S ternary alloys. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a method for preparing Ba using a molecular precursor route. x Pb 1-x The method for S alloying first involves synthesizing barium dibutyldithiocarbamate (BaDBuDTC) and lead dibutyldithiocarbamate (PbDBuDTC) solids. The two solids are then dispersed in carbon disulfide to obtain a mixed solution. Alloying is then carried out under nitrogen atmosphere and heated to obtain Ba. x Pb 1-x S alloy powder; or Ba alloy powder can be obtained by dropping the mixed solution onto quartz glass and reacting to alloy. x Pb1-x S alloy thin film. Ba alloy thin film obtained by this invention. x Pb 1-x S alloys exhibit a wide band gap and good stability under high humidity conditions, based on Ba x Pb 1-x Photodetectors constructed from Ba-Pb-S alloys exhibit extremely low dark current and excellent photoelectric response. Furthermore, by adjusting the molar ratio of Ba to Pb in the Ba-Pb-S alloy, Ba… x Pb 1-x The tunable bandgap of the S alloy lays an important foundation for further exploring the application of the Ba-Pb-S ternary alloy system in the optoelectronic field.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] A method for preparing Ba using a molecular precursor route x Pb 1-x The method for S alloying involves first synthesizing barium dibutyldithiocarbamate and lead dibutyldithiocarbamate solids, then dispersing the two solids with carbon disulfide to obtain a mixed solution, and finally alloying them under nitrogen atmosphere to obtain Ba. x Pb 1-x S alloy powder; or Ba alloy powder can be obtained by dropping the mixed solution onto quartz glass and reacting to alloy. x Pb 1-x S alloy thin film.

[0008] The above preparation method includes the following specific steps:

[0009] (1) Synthesis of the molecular precursor barium dibutyldithiocarbamate (BaDBuDTC): Barium hydroxide octahydrate and dibutylamine were placed in a round-bottom flask and stirred at room temperature; then carbon disulfide was slowly added and stirred, and the mixture was dried by rotary evaporation to obtain solid BaDBuDTC.

[0010] (2) Synthesis of molecular precursor lead dibutyldithiocarbamate (PbDBuDTC): Lead oxide and dibutylamine were placed in a round-bottom flask and stirred at room temperature; then carbon disulfide was slowly added and stirred, and then dried by rotary evaporation to obtain solid PbDBuDTC.

[0011] (3)Ba x Pb 1-x Synthesis of S alloy: The BaDBuDTC solid obtained in step (1) and the PbDBuDTC solid obtained in step (2) were uniformly dispersed with carbon disulfide to obtain a mixed solution.

[0012] ①Ba x Pb 1-xPreparation of S alloy powder: The mixed solution was transferred to a crucible and placed in a tube furnace. After slowly replacing the nitrogen, the temperature was raised to react and alloy, and then cooled to obtain Ba. x Pb 1-x S alloy powder;

[0013] ②Ba x Pb 1-x Preparation of S alloy thin film: The mixed solution was drop-coated onto quartz glass and reacted and alloyed in a tube furnace to obtain Ba. x Pb 1-x S alloy thin film.

[0014] Furthermore, in step (1), the molar ratio of barium hydroxide octahydrate, dibutylamine, and carbon disulfide added is 4-6:9-11:10-13, and the mixture is stirred at 60-70℃ for 3.5-4.5 hours; the rotary evaporation temperature is 70-75℃; and the drying temperature is 60-70℃ for 23-26 hours.

[0015] Furthermore, in step (2), the molar ratio of lead oxide, dibutylamine, and carbon disulfide is 4-6:9-11:10-13, and the mixture is stirred at 30-40°C for 3.5-4.5 hours; the rotary evaporation temperature is 70-75°C; and the drying temperature is 60-70°C for 23-26 hours.

[0016] Furthermore, the purity of barium hydroxide octahydrate in steps (1)-(2) is higher than 98%, the purity of lead oxide is higher than 99.9%, and the purity of dibutylamine is higher than 99%.

[0017] Furthermore, in step (3), the molar ratio of BaDBuDTC and PbDBuDTC added is 1-2:1-2; the nitrogen gas is replaced 2-4 times; the temperature is increased from room temperature to 680-720℃ within 110-130 min; the reaction alloying temperature is 680-720℃ and maintained for 4-4.5 h.

[0018] Furthermore, the carbon disulfide described in steps (1)-(3) has a purity higher than 98%.

[0019] Furthermore, the nitrogen purity in step (3) is higher than 99.99%.

[0020] This invention provides a Ba prepared by the above method. x Pb 1-x S alloy powder, the Ba x Pb 1-x S alloy powder is Ba 0.5 Pb 0.5 S alloy powder can be used in solar cells or photodetectors.

[0021] This invention provides a Ba prepared by the above method. x Pb 1-x S alloy thin film, the Ba x Pb 1-x S alloy thin film is Ba 0.5 Pb 0.5 S-film can be used in semiconductor devices.

[0022] Beneficial effects:

[0023] This invention successfully synthesized Ba using a molecular precursor route. x Pb 1-x S alloy powder and film, Ba 0.5 Pb 0.5 The absorption coefficient of S alloy in the visible light region reaches 10. 4 cm -1 With a band gap of 1.77 eV and good storage stability under high humidity conditions, it effectively fills the technological gap in the synthesis of Ba-Pb-S ternary alloys; based on Ba 0.5 Pb 0.5 Photodetectors constructed from Ba-Pb-S alloys exhibit extremely low dark current and excellent photoelectric response. By adjusting the molar ratio of Ba to Pb in the Ba-Pb-S alloy, the bandgap width of the alloy can be made tunable, paving the way for advancements in Ba-Pb-S photodetector technology. x Pb 1-x S alloys provide important reference for the development of optoelectronic applications. Attached Figure Description

[0024] Figure 1 Ba 0.5 Pb 0.5 Schematic diagram of the preparation scheme for S alloy powder;

[0025] Figure 2 Ba 0.5 Pb 0.5 SEM images of S alloy thin films;

[0026] Figure 3 Ba 0.5 Pb 0.5 HAADF-STEM images and EDS elemental spectra of S alloy; where a: Ba 0.5 Pb 0.5 HAADF-STEM images of S alloy, b: EDS elemental spectrum of Ba, c: EDS elemental spectrum of Pb, d: EDS elemental spectrum of S.

[0027] Figure 4 Ba 0.5 Pb 0.5Absorption spectrum and optical bandgap fitting diagram of S alloy; where a: Ba 0.5 Pb 0.5 Absorption spectrum of S alloy, b: Ba 0.5 Pb 0.5 Optical bandgap fitting diagram of S alloy;

[0028] Figure 5 Ba 0.5 Pb 0.5 XRD pattern of S alloy under high humidity conditions;

[0029] Figure 6 Ba 0.5 Pb 0.5 S-based photoelectric application potential evaluation diagram; where a: photodetector based on Ba0.5Pb0.5S alloy, b: photodetector based on Ba 0.5 Pb 0.5 Dynamic response diagram of S alloy 365nm LED switching device;

[0030] Figure 7 Ba with different Ba-Pb molar ratios x Pb 1-x XRD pattern of S alloy;

[0031] Figure 8 Ba with different Ba-Pb molar ratios x Pb 1-x Absorption spectrum of S alloy;

[0032] Figure 9 Ba with different Ba-Pb molar ratios x Pb 1-x Bandgap fitting diagram of S alloy. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be described in detail below. The described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0034] Example 1: Ba x Pb 1-x Preparation of S alloy

[0035] (1) Synthesis of the molecular precursor barium dibutyldithiocarbamate (BaDBuDTC): 5 mmol of barium hydroxide octahydrate and 10 mmol of dibutylamine were placed in a 25 ml round-bottom flask and stirred at room temperature. Then, 11 mmol of carbon disulfide was slowly added. After stirring at 65 °C for 4 h, the residue of carbon disulfide and water in the reaction was removed by rotary evaporation under vacuum at 70 °C. Finally, the product was dried under vacuum at 65 °C for 24 h to obtain solid BaDBuDTC, which can be stored in air without deterioration.

[0036] (2) Synthesis of molecular precursor lead dibutyldithiocarbamate (PbDBuDTC): 5 mmol lead oxide and 10 mmol dibutylamine were placed in a 25 ml round-bottom flask and stirred at room temperature. Then 11 mmol carbon disulfide was slowly added. After stirring at 35 °C for 4 h, the mixture was rotary evaporated under vacuum at 70 °C to remove residual carbon disulfide and water. Finally, the mixture was dried under vacuum at 65 °C for 24 h to obtain solid PbDBuDTC, which can be stored in air without deterioration.

[0037] (3)Ba 0.5 Pb 0.5 Synthesis of S alloy: 1 mmol BaDBuDTC solid obtained in step (1) and 1 mmol PbDBuDTC solid obtained in step (2) were uniformly dispersed in a glass sample bottle with 2 ml of carbon disulfide to obtain a mixed solution;

[0038] ①Ba 0.5 Pb 0.5 Preparation of S alloy powder samples: such as Figure 1 As shown, the mixed solution was transferred to a crucible and placed in a tube furnace. After three slow nitrogen replacements, the temperature was raised from room temperature to 700℃ in a nitrogen atmosphere for 120 minutes. After maintaining the temperature at 700℃ for 4 hours, it was naturally cooled to room temperature to obtain Ba. 0.5 Pb 0.5 S alloy powder samples were used in subsequent experiments.

[0039] ②Ba 0.5 Pb 0.5 Preparation of S alloy thin film: The mixed solution was drop-coated onto quartz glass using a dropper, and then held at 700℃ for 4 hours in a tube furnace to obtain Ba alloy film loaded on quartz glass. 0.5 Pb 0.5 S alloy thin film.

[0040] Example 2: Ba x Pb 1-x Evaluation of S alloy thin films

[0041] Dense thin films are a prerequisite for most semiconductor device applications. The Ba obtained in Example 1... 0.5 Pb0.5 The microstructure of the S alloy thin film was observed using a scanning electron microscope (SEM), such as... Figure 2 As shown, Ba 0.5 Pb 0.5 The S alloy thin film exhibited good compactness in scanning electron microscope (SEM) images, providing an important reference for the preparation of this alloy thin film.

[0042] Example 3: Ba x Pb 1-x Confirmation of S alloy synthesis

[0043] The lattice spacing and elemental distribution of the alloy were analyzed using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Figure 3 As shown in a, Ba 0.5 Pb 0.5 The lattice spacings of the S alloy are 0.309 nm and 0.219 nm, respectively. These values ​​fall between the (200) and (022) lattice spacings of lead sulfide (0.297 nm and 0.210 nm) and barium sulfide (0.319 nm and 0.226 nm), respectively, confirming that Ba... 0.5 Pb 0.5 Synthesis of S alloy.

[0044] Secondly, Figure 3 Energy-dispersive X-ray spectroscopy (EDS) analysis was performed on the region captured in a, such as... Figure 3 As shown in bd, Ba, Pb, and S are uniformly distributed in this region, further confirming that Ba 0.5 Pb 0.5 The formation of S alloy.

[0045] Example 4: Ba x Pb 1-x Absorption spectrum and optical band gap fitting of S alloy

[0046] Ba was determined using ultraviolet-visible-near-infrared spectroscopy. 0.5 Pb 0.5 Absorption spectrum and optical band gap of S alloy. For example... Figure 4 As shown in Figure a, the absorption coefficient in the visible light region reaches 10. 4 cm -1 . Figure 4 As shown in b, the direct bandgap width of the alloy powder with a Ba:Pb molar ratio of 1:1 is 1.77 eV. The alloy prepared by this invention has a wide bandgap, which is within the optimal bandgap range of the top cell of a tandem solar cell, and can be used as the absorber layer material of the top cell of a tandem solar cell.

[0047] Example 5: Ba x Pb 1-xStability evaluation of S alloy

[0048] Will Ba 0.5 Pb 0.5 The S alloy was exposed to an environment with a relative humidity of 60% for 30 days, and its stability to moisture was then investigated. Figure 5 As shown, in a high humidity environment, Ba 0.5 Pb 0.5 The S alloy retains its original alloy structure and exhibits significant stability compared to organic-inorganic metal halide perovskite materials.

[0049] Example 6: Ba x Pb 1-x Evaluation of the optoelectronic application potential of S alloy devices

[0050] To further evaluate the optoelectronic application potential of the alloy, a photodetector with a width of 0.6 mm and a length of 4 mm was constructed (its structural schematic diagram is shown in Figure 1). Figure 6 As shown in figure a), the transient photoelectric response of the detector was experimentally tested using a wavelength of 365 nm and an optical power density of 0.94 mW / cm². 2 The photoelectric response of the device is detected by the light emitted by the LED. Figure 6 As shown in Figure b, at a bias voltage of 1V, the detector exhibits very low dark current (1.11nA) and high photocurrent on / off repeatability. Furthermore, the detector demonstrates a fast response speed, with rise and decay times of less than 50ms. This indicates that the device possesses extremely low dark current and excellent photoresponse capability.

[0051] In addition, Ba x Pb 1-x The Ba:Pb molar ratios in S alloys were adjusted to 2:1, 1:1, and 1:2, and the band gap characteristics of the different alloys were investigated. Figure 7-9 As shown, by adjusting the Ba:Pb molar ratio, while maintaining the original alloy structure, Ba... x Pb 1-x S alloys can maintain a high light absorption coefficient while achieving adjustable band gap characteristics.

[0052] In summary, the method of the present invention prepares Ba x Pb 1-x S alloys can be used in the optoelectronic field.

Claims

1. A method for producing Ba x Pb 1-x S alloy by a molecular precursor route, characterized in that, First, barium dibutyl dithiocarbamate and lead dibutyl dithiocarbamate solids are synthesized, the two solids are dispersed with carbon disulfide to obtain a mixed solution, and alloying is obtained by heating and reacting under a nitrogen environment, to obtain Ba x Pb 1-x S alloy powder; The method specifically comprises the following steps: (1) synthesis of the molecular precursor barium dibutyl dithiocarbamate: stirring barium hydroxide octahydrate and dibutylamine at room temperature; then adding carbon disulfide, stirring, and rotary evaporation drying to obtain BaDBuDTC solid; (2) synthesis of the molecular precursor lead dibutyl dithiocarbamate: stirring lead oxide and dibutylamine at room temperature; then adding carbon disulfide, stirring, and rotary evaporation drying to obtain PbDBuDTC solid; (3) Ba x Pb 1-x Synthesis of Ba-Pb-S alloy: the BaDBuDTC solid obtained in step (1) and the PbDBuDTC solid obtained in step (2) are uniformly dispersed with carbon disulfide to obtain a mixed solution; Ba x Pb 1-x Preparation of Ba x Pb 1-x S alloy powder; the nitrogen replacement times are 2-4 times; the temperature rising is from room temperature to 680-720 °C in 110-130 min; the reaction alloying temperature is 680-720 °C, and the holding time is 4-4.5 h; and the nitrogen purity is higher than 99.99%.

2. The Ba of claim 1 x Pb 1-x A method for producing a Pb In step (1), the molar ratio of the added barium hydroxide octahydrate, dibutylamine, and carbon disulfide is 4-6:9-11:10-13, and stirring is performed at 60-70°C for 3.5-4.5h; the rotary evaporation temperature is 70-75°C; and the drying temperature is 60-70°C, and the drying time is 23-26h.

3. The Ba of claim 1 x Pb 1-x A method for producing a Pb In step (2), the molar ratio of the added lead oxide, dibutylamine, and carbon disulfide is 4-6:9-11:10-13, and stirring is performed at 30-40°C for 3.5-4.5h; the rotary evaporation temperature is 70-75°C; and the drying temperature is 60-70°C, and the drying time is 23-26h.

4. The Ba of claim 1 x Pb 1-x A method for producing a Pb In steps (1)-(2), the purity of the barium hydroxide octahydrate is higher than 98%, the purity of the lead oxide is higher than 99.9%, and the purity of the dibutylamine is higher than 99%.

5. The Ba of claim 1 x Pb 1-x A method for producing a Pb In step (3), the molar ratio of the added BaDBuDTC and PbDBuDTC is 1-2:1-2.

6. The Ba of claim 1 x Pb 1-x A method for producing a Pb In steps (1)-(3), the purity of the carbon disulfide is higher than 98%.

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