CsPbI 3 has recently received tremendous attention as a possible absorber of perovskite solar cells (PSCs). However, CsPbI 3 -based PSCs have yet to achieve the high performance of the hybrid PSCs. In this work, we performed a density functional theory (DFT) study using the Cambridge Serial Total Energy Package (CASTEP) code for the cubic CsPbI 3 absorber to compare and evaluate its structural, electronic, and optical properties. The calculated electronic band gap ( E g ) using the GGA-PBE approach of CASTEP was 1.483 eV for this CsPbI 3 absorber. Moreover, the computed density of states (DOS) exhibited the dominant contribution from the Pb-5d orbital, and most charges also accumulated for the Pb atom as seen from the electronic charge density map. Fermi surface calculation showed multiband character, and optical properties were computed to investigate the optical response of CsPbI 3 . Furthermore, we used IGZO, SnO 2 , WS 2 , CeO 2 , PCBM, TiO 2 , ZnO, and C 60 as the electron transport layers (ETLs) and Cu 2 O, CuSCN, CuSbS 2 , Spiro-MeOTAD, V 2 O 5 , CBTS, CFTS, P3HT, PEDOT:PSS, NiO, CuO, and CuI as the hole transport layers (HTLs) to identify the best HTL/CsPbI 3 /ETL combinations using the SCAPS-1D solar cell simulation software. Among 96 device structures, the best-optimized device structure, ITO/TiO 2 /CsPbI 3 /CBTS/Au, was identified, which exhibited an efficiency of 17.9%. The effect of the absorber and ETL thickness, series resistance, shunt resistance, and operating temperature was also evaluated for the six best devices along with their corresponding generation rate, recombination rate, capacitance–voltage, current density–voltage, and quantum efficiency characteristics. The obtained results from SCAPS-1D were also compared with wxAMPS simulation results.

BackgroundChronic arsenic exposure has been shown to cause liver damage. However, serum hepatic enzyme activity as recognized on liver function tests (LFTs) showing a dose-response relationship with arsenic exposure has not yet been clearly documented. The aim of our study was to investigate the dose-response relationship between arsenic exposure and major serum enzyme marker activity associated with LFTs in the population living in arsenic-endemic areas in Bangladesh.MethodsA total of 200 residents living in arsenic-endemic areas in Bangladesh were selected as study subjects. Arsenic concentrations in the drinking water, hair and nails were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The study subjects were stratified into quartile groups as follows, based on concentrations of arsenic in the drinking water, as well as in subjects' hair and nails: lowest, low, medium and high. The serum hepatic enzyme activities of alkaline phosphatase (ALP), aspartate transaminase (AST) and alanine transaminase (ALT) were then assayed.ResultsArsenic concentrations in the subjects' hair and nails were positively correlated with arsenic levels in the drinking water. As regards the exposure-response relationship with arsenic in the drinking water, the respective activities of ALP, AST and ALT were found to be significantly increased in the high-exposure groups compared to the lowest-exposure groups before and after adjustments were made for different covariates. With internal exposure markers (arsenic in hair and nails), the ALP, AST and ALT activity profiles assumed a similar shape of dose-response relationship, with very few differences seen in the higher groups compared to the lowest group, most likely due to the temporalities of exposure metrics.ConclusionsThe present study demonstrated that arsenic concentrations in the drinking water were strongly correlated with arsenic concentrations in the subjects' hair and nails. Further, this study revealed a novel exposure- and dose- response relationship between arsenic exposure metrics and serum hepatic enzyme activity. Elevated serum hepatic enzyme activities in the higher exposure gradients provided new insights into arsenic-induced liver toxicity that might be helpful for the early prognosis of arsenic-induced liver diseases.

Here a combined DFT, SCAPS-1D, and wxAMPS frameworks are used to investigate the optimized designs of Cs2BiAgI6 lead-free double perovskite-based solar cells from ninety-six device structures using various electron and hole charge transport layers.

Lead-free Cs2BiAgI6 has garnered a lot of research interest recently due to its suitability as a potential absorber layer in the solar cell (SC) architecture owing to its low cost, good stability, and high efficiency. The main highlight of this research work includes the photovoltaic (PV) performance enhancement of Cs2BiAgI6 double perovskite solar cells (PSCs) by optimizing the optoelectronic parameters of the absorber, electron transport layer (ETL), hole transport layer (HTL), and various interface layers. Solar Cell Capacitance Simulator One dimension (SCAPS-1D) numerical simulation was used to optimize the performance of Cs2BiAgI6 absorber-based SCs consisting of copper barium thiostannate (CBTS) as the HTL and TiO2, PCBM, ZnO, IGZO, SnO2, and WS2 as ETLs. The role of the non-lead cesium-based halide perovskite absorber layer in the improvement of the SC performance was systematically investigated through a variation in the thickness, doping density, and defect density of the absorber layer, ETL, and HTL. The performance of the investigated device architectures is largely dependent on the thickness of the absorber layer, acceptor density, defect density, and the combination of different ETLs and HTLs. We found that TiO2, PCBM, ZnO, IGZO, SnO2, and WS2 ETL-based optimized devices recorded a power conversion efficiency (PCE) of 23.14, 23.71, 23.69, 22.97, 23.61, and 21.72%, respectively. Furthermore, the effect of series and shunt resistances, temperature, capacitance, and Mott–Schottky for the six optimized devices was estimated along with the computation of the corresponding generation and recombination rates, current density–voltage (J–V), and quantum efficiency (QE) characteristics. The PV parameters obtained from this comprehensive analysis are finally compared with the earlier published theoretical and experimental reports on Cs2BiAgI6 absorber-based SCs.

Cesium tin chloride (CsSnCl3) is a potential and competitive absorber material for lead-free perovskite solar cells (PSCs). The full potential of CsSnCl3 not yet been realized owing to the possible challenges of defect-free device fabrication, non-optimized alignment of the electron transport layer (ETL), hole transport layer (HTL), and the favorable device configuration. In this work, we proposed several CsSnCl3-based solar cell (SC) configurations using one dimensional solar cell capacitance simulator (SCAPS-1D) with different competent ETLs like indium–gallium–zinc–oxide (IGZO), tin-dioxide (SnO2), tungsten disulfide (WS2), ceric dioxide (CeO2), titanium dioxide (TiO2), zinc oxide (ZnO), C60, PCBM, and HTLs of cuprous oxide (Cu2O), cupric oxide (CuO), nickel oxide (NiO), vanadium oxide (V2O5), copper iodide (CuI), CuSCN, CuSbS2, Spiro MeOTAD, CBTS, CFTS, P3HT, PEDOT:PSS. Simulation results revealed that ZnO, TiO2, IGZO, WS2, PCBM, and C60 ETLs-based halide perovskites with ITO/ETLs/CsSnCl3/CBTS/Au heterostructure exhibited outstanding photoconversion efficiency retaining nearest photovoltaic parameters values among 96 different configurations. Further, for the six best-performing configurations, the effect of the CsSnCl3 absorber and ETL thickness, series and shunt resistance, working temperature, impact of capacitance, Mott–Schottky, generation and recombination rate, current–voltage properties, and quantum efficiency on performance were assessed. We found that ETLs like TiO2, ZnO, and IGZO, with CBTS HTL can act as outstanding materials for the fabrication of CsSnCl3-based high efficiency (η ≥ 22%) heterojunction SCs with ITO/ETL/CsSnCl3/CBTS/Au structure. The simulation results obtained by the SCAPS-1D for the best six CsSnCl3-perovskites SC configurations were compared by the wxAMPS (widget provided analysis of microelectronic and photonic structures) tool for further validation. Furthermore, the structural, optical and electronic properties along with electron charge density, and Fermi surface of the CsSnCl3 perovskite absorber layer were computed and analyzed using first-principle calculations based on density functional theory. Thus, this in-depth simulation paves a constructive research avenue to fabricate cost-effective, high-efficiency, and lead-free CsSnCl3 perovskite-based high-performance SCs for a lead-free green and pollution-free environment.