A perfect crystalline phases of cuprous oxide were synthesized using electrochemical method at different duration ( 15, 30 and 60 min). The deposited samples were examined by XRD, SEM, UV–Vis absorption and Mott-Schottky measurements. The effect of the deposition time on the optical and dielectric properties of Cu₂O was studied in detail. The x-ray diffraction indicated increasing of crystallinity and crystallite size with increasing of deposition time. SEM micrographs exhibited grains with three-faced pyramid shape and grains size increased with improvement of crystallinity. Optical study is performed to calculate optical band gap (E_g), absorption coefficient (α), extinction coefficient (k), refractive index (n), dielectric constants (ε), urbach energy (E_U) and optical conductivity (σ_opt) using the transmittance and absorption spectra in the wavelength range of 400–1100 nm. Among all grown samples, the film deposited at 60 min shows interesting optical and dielectric properties. The Mott-Schottky analysis shows that the film deposited at 60 min has a low carrier density compared to samples deposited in other deposition times.

Eco-friendly lead-free perovskite CH ₃ NH ₃ SnI ₃ (MASnI ₃ ) based solar cell device was simulated using the one-dimensional solar capacitance tool (SCAPS 1D). In this work, we investigate the effect of several parameters such as the thickness and the defect density in the absorber layer. We focus on the effect of defect densities at the TiO ₂ /MASnI ₃ , MASnI ₃ /Spiro-OMeTAD interfaces on the photovoltaic performances. Our results show that the best performances were obtained with an absorber thickness layer kept of 1.1 μ m, and for low defect densities in the active layer and at the TiO ₂ /MASnI ₃ interface. In addition, we have studied the effect of various hole transport layers (HTL) compounds such as Cu ₂ O, CuO, CuI, CuSCN, PTAA, PEDOT: PSS, and MEH-PPV. Our results show the significant impact of valence band offset and hole mobility on device performances. The champion device has a power conversion efficiency of 27.77%, a current density ( J _sc ) of 34.6 mA cm ⁻² , an open circuit voltage ( V _oc ) of 0.96 V and a fill factor of 83.34%. This work can provide imperative guidelines to researchers for the design of efficient eco-friendly perovskite solar cells.