BaZrS₃ chalcogenide perovskites have emerged as a promising absorber due to their exceptional properties. However, there are no experimental reports on the applicability of BaZrS₃ in photovoltaics. Thus, theoretical knowledge of device structure engineering is essential for its successful fabrication. In this regard, we have proposed various BaZrS₃ device configurations by altering 12 electron transport layers (ETLs) in combination with 13 hole transport layers (HTLs) using SCAPS-1D, wherein a total of 782 devices are simulated by tuning the thickness, carrier concentration, and defect density of BaZrS₃, ETLs, and HTLs. Interestingly, the absorber's thickness optimization enhanced the absorption in the device by 2.31 times, elevating the generation rate of charge carriers, while the increase in its carrier concentration boosted the built-in potential from 0.8 to 1.68 V, reducing the accumulation of charge carriers at the interfaces. Notably, on further optimization of ETL and HTL combinations, the best power conversion efficiency (PCE) of 28.08% is achieved for FTO/ZrS₂/BaZrS₃/SnS/Au, occurring due to the suppressed barrier height of 0.1 eV at the ZrS₂/BaZrS₃ interface and degenerate behavior of SnS, which increased charge carrier transportation and conductivity of the devices. Upon optimizing the work function, an ohmic contact is achieved for Pt, boosting the PCE to 28.17%. Finally, the impact of Ti alloying on BaZrS₃ properties is examined on the champion FTO/ZrS₂/BaZrS₃/SnS/Pt device where the maximum PCE of 32.58% is obtained for Ba(Zr_0.96,Ti_0.04)S₃ at a thickness of 700 nm due to extended absorption in the NIR region. Thus, this work opens doors to researchers for the experimental realization of high PCE in BaZrS₃ devices.

The remarkable performance of copper indium gallium selenide (CIGS)-based double heterojunction (DH) photovoltaic cells is presented in this work. To increase all photovoltaic performance parameters, in this investigation, a novel solar cell structure (FTO/SnS₂/CIGS/Sb₂S₃/Ni) is explored by utilizing the SCAPS-1D simulation software. Thicknesses of the buffer, absorber and back surface field (BSF) layers, acceptor density, defect density, capacitance–voltage (C–V), interface defect density, rates of generation and recombination, operating temperature, current density, and quantum efficiency have been investigated for the proposed solar devices with and without BSF. The presence of the BSF layer significantly influences the device's performance parameters including short-circuit current (J_sc), open-circuit voltage (V_oc), fill factor (FF), and power conversion efficiency (PCE). After optimization, the simulation results of a conventional CIGS cell (FTO/SnS₂/CIGS/Ni) have shown a PCE of 22.14% with V_oc of 0.91 V, J_sc of 28.21 mA cm⁻², and FF of 86.31. Conversely, the PCE is improved to 31.15% with V_oc of 1.08 V, J_sc of 33.75 mA cm⁻², and FF of 88.50 by introducing the Sb₂S₃ BSF in the structure of FTO/SnS₂/CIGS/Sb₂S₃/Ni. These findings of the proposed CIGS-based double heterojunction (DH) solar cells offer an innovative method for realization of high-efficiency solar cells that are more promising than the previously reported traditional designs.

We report the numerical simulation of an efficient FA₄GeSbCl₁₂ solar cell with a PCE of 22.5%. This study provides novel device design and explanations to understand device physics mainly based on CBO & VBO at ETL/absorber & absorber/HTL interfaces.

Cadmium sulfide (CdS) nanoparticles were synthesized by chemical precipitation method using cadmium chloride (CdCl₂), sodium sulfide (Na₂S) and water as a solvent by varying temperatures from 20–80 °C. The nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), High-resolution transmission electron microscopy (HR-TEM) and UV-Visible spectroscopy. XRD pattern revealed cubic crystal structure for all the synthesized CdS nanoparticles. Raman spectra showed first and second order longitudinal optical (LO) phonon vibrational modes of CdS. The size of CdS nanoparticles was found to be in the range of 15–80 nm by FE-SEM analysis, in all cases. The atomic percentage of cadmium and sulfur was confirmed to be 1:1 from EDS analysis. TEM micrograph depicts the spherical shape of the particles and the size is in the range of 15–85 nm while HR-TEM images of CdS nanoparticles exhibit well-resolved lattice fringes of the cubic structure of CdS. The optical properties of CdS were examined by UV-Visible spectroscopy which showed variation in absorption band from 460–480 nm. The band gap was calculated from the absorption edge and found to be in the range of 3.2–3.5 eV which is greater than the bulk CdS.

Cu₂ZnSn(S,Se)₄ is a non-toxic, earth-abundant photovoltaic absorber. However, its efficiency is limited by a large open circuit voltage (V_OC) deficit occurring due to its antisite defects and improper band alignment with toxic CdS buffer. Therefore, finding an absorber and non-toxic buffers that reduce V_OC deficit is crucial. Herein, for the first time, Ag₂BaTiSe₄ is proposed as an alternative absorber using SCAPS-1D wherein a new class of alkaline earth metal chalcogenide such as MgS, CaS, SrS, and BaS is applied as buffers, and their characteristics are compared with CdS to identify their potential and suitability. The buffer and absorber properties are elucidated by tuning their thickness, carrier concentration, and defect density. Interestingly, optimization of the buffer’s carrier concentration suppressed the barrier height and accumulation of charge carriers at the absorber/buffer interface, leading to efficiencies of 18.81%, 17.17%, 20.6%, 20.85%, 20.08% in MgS, CaS, SrS, BaS, and CdS-based solar cells respectively. Upon optimizing Ag₂BaTiSe_4, MoSe₂, and interface defects maximum efficiency of > 28% is achieved with less V_OC loss (~ 0.3 V) in all solar cells at absorber’s thickness, carrier concentration, and defect density of 1 µm, 10¹⁸ cm⁻³, 10¹⁵ cm⁻³ respectively, underscoring the promising nature of Ag₂BaTiSe₄ absorber and new alkaline earth metal chalcogenide buffers in photovoltaics.