Improving photoluminescence properties and reducing recombination of CsPbBr3 perovskite through lithium doping.

This study investigates the impact of lithium doping on the structural and photophysical properties of spin-coated CsPbBr3 perovskite thin films. The deposited films display a pristine structure, preferentially growing along the (220) direction, and exhibit high-quality green photoluminescence at around 530 nm. The doping leads to an improvement in the optical properties of the films, as evidenced by a stronger photoluminescence (PL) intensity compared to undoped CsPbBr3, particularly at temperatures below 200 K. The increase in PL intensity suggests a decrease in defects and surface passivation. Additionally, the decrease in the power-law exponent ß from 1.6 to 1.0 indicates a reduction in non-radiative recombination, likely due to trap states filling with free electrons induced by the doping. Overall, doping with lithium reduces non-radiative recombination, fills trap states, and reduces band tail/activation energy, leading to improved optoelectronic properties of the films. This investigation provides insights into the photophysical properties of the Li-CsPbBr3 absorber layer and the recombination mechanism, and helps to unravel new methods for the development of high-stability, high-performance perovskite thin-film solar cells and optoelectronic devices.

Growth of copper indium diselenide ternary thin films (CuInSe2) for solar cells: Optimization of electrodeposition potential and pH parameters.

Herein, copper indium diselenide ternary (CuInSe2) thin film has been deposited on Indium Tin Oxide (ITO) coated glass substrate by electrochemical deposition technique with different potential and pH solutions. CuInSe2 thin films were deposited by one-step electrodeposition before post-depot selenization at 450 °C for 30 min. The effect of potential and pH on the structural and optical properties of CuInSe thin film have been studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), and UV-Visible spectrometer. According to the X-ray diffraction (XRD) measurements, it was observed that all samples exhibit prominent reflections (112), (204/220), and (312/116) of tetragonal CuInSe2. The films electrodeposited at -0.8 V potential shows growth and peak values increasing in the (204/220) crystal direction within a pH range of 2.2, whereas the films electrodeposited at pH 2.6 tend to favor an increase in (112) peaks. We also noticed an improvement in surface morphology and adherent of CuInSe2 thin films electrodeposited at -0.8 V applied potential from the solution having pH 2.6. The band gaps of samples electrodeposited at -0.8V potentials from pH 2.6, 2.4, and 2.2 solutions were 1.15 eV, 1.25 eV, and 1.21 eV, respectively. As part of our investigation, we used a Solar Cell capacitance simulator (SCAPS) to perform our electrodeposited films. The most effective Power conversion efficiency (PCE) was obtained for thin films electrodeposited at -0.8 V within the solution having pH 2.4.

The Structural and Electrochemical Properties of CuCoO2 Crystalline Nanopowders and Thin Films: Conductivity Experimental Analysis and Insights from Density Functional Theory Calculations.

A novel manufacturing process is presented for producing nanopowders and thin films of CuCoO2 (CCO) material. This process utilizes three cost-effective synthesis methods: hydrothermal, sol-gel, and solid-state reactions. The resulting delafossite CuCoO2 samples were deposited onto transparent substrates through spray pyrolysis, forming innovative thin films with a nanocrystal powder structure. Prior to the transformation into thin films, CuCoO2 powder was first produced using a low-cost approach. The precursors for both powders and thin films were deposited onto glass surfaces using a spray pyrolysis process, and their characteristics were examined through X-ray diffraction, scanning electron microscopy, HR-TEM, UV-visible spectrophotometry, and electrochemical impedance spectroscopy (EIS) analyses were conducted to determine the conductivity in the transversal direction of this groundbreaking material for solar cell applications. On the other hand, the sheet resistance of the samples was investigated using the four-probe method to obtain the sheet resistivity and then calculate the in-plane conductivity of the samples. We also investigated the aging characteristics of different precursors with varying durations. The functional properties of CuCoO2 samples were explored by studying chelating agent and precursor solution aging periods using Density Functional Theory calculations (DFT). A complementary Density Functional Theory study was also performed in order to evaluate the electronic structure of this compound. Resuming, this study thoroughly discusses the synthesis of delafossite powders and their conversion into thin films, which hold potential as hole transport layers in transparent optoelectronic devices.

Methylammonium lead triiodide perovskite-based solar cells efficiency: Insight from experimental and simulation.

This work deals with the growth investigation of the methylammonium lead triiodide (MAPbI3) thin films prepared by the spin coating technique. Firstly, MAPbI3 films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and UV-Visible spectroscopy as well as photoluminescence techniques are used to calculate the band gap energy. Indeed, the high-quality MAPbI3 perovskite films were obtained by using Chlorobenzene as an antisolvent with good crystallinity, large grain sizes, and higher absorption compared to MAPbI3 treated by toluene. Secondly, the performance of FTO/TiO2/MAPbI3/Spiro OMeTAD/Au perovskite solar cell was evaluated using a numerical simulation of the Solar Cell by SCAPS simulator. The effect of the structural and physical parameters of MAPbI3 absorber layer and HTL with the different antisolvents, including thickness, defect density, total charge density, donor density and electron affinity. Obtained results are: Jsc of 25.96 mA/cm2, PCE of 30.70%, Voc of 1.259 V, FF of 88.93% of MAPbI3-based solar cells when MAPbI3 is treated by toluene. However, for MAPbI3- Chlorobenzene, the I-V characteristics are rather: Jsc of 28.18 mA/cm2, PCE of 31.81%, FF of 88.19% and Voc of 1.200 V. It is pointed out that the use of chlorobenzene may be of interest to improve the perovskites solar cells performances.

Manufacture of different oxides with high uniformity for copper zinc tin sulfide (CZTS) based solar cells.

Herein, we investigate different oxides layers: Zinc Oxide (ZnO), Nickel Oxide (NiO), Titanium Oxide (TiO2), and Copper Oxide (CuO), which are effective materials for Copper Zinc Tin Sulfide (CZTS) based solar cells due to their excellent electrical and optical properties. The different oxide films were prepared using spray pyrolysis as a low-cost technique. Then, the films were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and UV-Visible to examine different properties. The XRD pattern showed that the different oxides are polycrystalline. ZnO exhibits a hexagonal wurtzite structure, and NiO is cubic. For the TiO2, (101) and (004) peaks have been identified, corresponding to the tetragonal anatase phase. CuO showed diffraction peaks corresponding to the monoclinic structures. The SEM results revealed that the deposited films consist of crystals with low crystallinity for NiO and good crystallinity for the rest oxides. The band gap was calculated from the UV-visible measurement. We obtained 3.26 eV, 3.34 eV, 3.2 eV, and 1.7 eV for ZnO, NiO, TiO2, and CuO respectively. The performance of the CZTS-based solar cell was checked by using the simulator SCAPS. ZnO and TiO2 were used as window layers where CZTS efficiencies are 24.40% and 24.54%, respectively. These findings show that ZnO and TiO2 films can be produced by low-cost techniques such as spray pyrolysis to be used as windows and electron transport layers for CZTS-based solar cells.

Green synthesis of copper oxide nanoparticles using Ephedra Alata plant extract and a study of their antifungal, antibacterial activity and photocatalytic performance under sunlight.

In the present work, copper oxide (CuO NPs) was synthesized by an eco-friendly, simple, low-cost, and economical synthesis method using Ephedra Alata aqueous plant extract as a reducing and capping agent. The biosynthesized CuO-NPs were compared with chemically obtained CuO-NPs to investigate the effect of the preparation method on the structural, optical, morphological, antibacterial, antifungal, and photocatalytic properties under solar irradiation. The CuO NPs were characterized using X-ray diffraction (XRD), UV-VIS spectroscopy, Fourier transform infrared spectrometer (FTIR) analysis, and field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX). The photocatalytic activities of biosynthetic CuO-NPs and chemically prepared CuO-NPs were studied using methylene blue upon exposure to solar irradiation. The results showed that the biosynthesized CuO photocatalyst was more efficient than the chemically synthesized CuO-NPs for Methylene Blue (MB) degradation under solar irradiation, with MB degradation rates of 93.4% and 80.2%, respectively. In addition, antibacterial and antifungal activities were evaluated. The disk diffusion technique was used to test the biosynthesized CuO-NPs against gram-negative bacteria, Staphylococcus aureus and Bacillus subtilis, as well as C. Albicans and S. cerevisiae. The biosynthesized CuO-NPs showed efficient antibacterial and antifungal activity. The obtained results revealed that the biosynthesized CuO-NPs can play a vital role in the destruction of pathogenic bacteria, the degradation of dyes, and the activity of antifungal agents in the bioremediation of industrial and domestic waste.

Manufacture of High-Efficiency and Stable Lead-Free Solar Cells through Antisolvent Quenching Engineering.

Antisolvent quenching has shown to significantly enhance several perovskite films used in solar cells; however, no studies have been conducted on its impact on MASnI3. Here, we investigated the role that different antisolvents, i.e., diethyl ether, toluene, and chlorobenzene, have on the growth of MASnI3 films. The crystallinity, morphology, topography, and optical properties of the obtained thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) measurements, and UV-visible spectroscopy. The impact of the different antisolvent treatments was evaluated based on the surface homogeneity as well as the structure of the MASnI3 thin films. In addition, thermal annealing was optimized to control the crystallization process. The applied antisolvent was modified to better manage the supersaturation process. The obtained results support the use of chlorobenzene and toluene to reduce pinholes and increase the grain size. Toluene was found to further improve the morphology and stability of thin films, as it showed less degradation after four weeks under dark with 60% humidity. Furthermore, we performed a simulation using SCAPS-1D software to observe the effect of these antisolvents on the performance of MASnI3-based solar cells. We also produced the device FTO/TiO2/MASnI3/Spiro-OMeTAD/Au, obtaining a remarkable photoconversion efficiency (PCE) improvement of 5.11% when using the MASnI3 device treated with chlorobenzene. A PCE improvement of 9.44% was obtained for the MASnI3 device treated with toluene, which also showed better stability. Our results support antisolvent quenching as a reproducible method to improve perovskite devices under ambient conditions.

Investigation of the Surface Coating, Humidity Degradation, and Recovery of Perovskite Film Phase for Solar-Cell Applications.

Presently, we inquire about the organic/inorganic cation effect on different properties based on structure, morphology, and steadiness in preparing a one-step solution of APbI3 thin films, where A = MA, FA, Cs, using spin coating. This study was conducted to understand those properties well by incorporating device modeling using SCAPS-1D software and to upgrade their chemical composition. X-ray diffraction (XRD) was used to analyze the crystal structures. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were conducted to characterize the surface morphology; photoluminescence, Transmission Electron Microscopy (TEM), and a UV-Visible spectrometer helped us to study the optical properties. The (110) plane is where we found the perovskite's crystalline structure. According to the XRD results and by changing the type of cation, we influence stabilization and the growth of the APbI3 absorber layer. Hither, a homogenous, smooth-surfaced, pinhole-free perovskite film and large grain size are results from the cesium cation. For the different cations, the band gap's range, revealed by the optical analysis, is from 1.4 to 1.8 eV. Moreover, the stability of CsPbI3 remains excellent for two weeks and in a ~60% humid environment. Based on the UV-Visible spectrometer and photoluminescence characterization, a numerical analysis for fabricated samples was also performed for stability analysis by modeling standard solar-cell structures HTL/APbI3/ETL. Modeling findings are in good agreement with experimental results that CsPbI3 is more stable, showing a loss % in PCE of 14.28%, which is smaller in comparison to FAPbI3 (44.46%) and MAPbI3 (20.24%).