Pd-F:SnO₂ thin films have been prepared by spray pyrolysis technique. Optimization has been done by doping SnO₂ with palladium at varying levels of concentration and then recording sheet resistance. The sheet resistivity has been observed to decrease gradually as at% Pd concentration is increased; an optimum sheet resistivity value of 2.71 × 10⁻² Ω cm has been recorded. The decrease in sheet resistivity has been attributed to presence of Pd ions which contribute in increment of charge carrier density. Using the optimum value of at% Pd doping, the same procedure has been repeated to study the effect of fluorine on Pd:SnO₂; an optimum value of 1.64 × 10⁻⁴ Ω cm sheet resistivity has been recorded. This decrease has been attributed to substitution of O⁻ with those of fluorine hence improving charge carrier density. The effect of passivation has been studied by comparing as prepared, annealed and passivated Pd-F:SnO₂ thin films. Annealing has been observed to decrease the sheet resistivity to 1.21 × 10⁻⁴ Ω cm, while passivation has the effect of increasing the sheet resistivity to 1.53 × 10⁻⁴ Ω cm which is attributed to effects resulting from annealing the samples in nitrogen gas atmosphere.

Efficient materials with good optoelectronic properties are required for the good performance of photovoltaic devices. In this work, we present findings of a theoretical investigation of the structural, electronic, elastic, mechanical, and optical properties of K₂CuX (X=As, Sb) ternary compounds. The computations were carried out by using the density functional theory (DFT) formalism as implemented in the quantum espresso (QE) software package. The calculated lattice constants of 19.1414 a.u (K₂CuAs) and 20.0041 a.u (K₂CuSb) are in agreement with the experimental results from the literature. The materials under study were found to have bandgaps of 1.050eV (K₂CuAs) and 1.129eV (K₂CuSb). The valence band was majorly formed by Cu-3d, As-2p, and Cu-4s states while the conduction band was majorly dominated by Cu-5p in K₂CuAs, whereas in K₂CuSb, the valence band was mainly formed by Cu-3d, Cu-4s, and Sb-3p states while the conduction band was majorly formed by Sb-3p and Cu-5p states. The investigated materials were found to be mechanically stable at zero pressure, ductile, and ionic. The optical absorption coefficient curves were found to cover the ultraviolet to visible (UV-Vis) regions, thus making K₂CuAs and K₂CuSb good UV-Vis absorbers hence their suitability for photovoltaic applications.

A new highly structured system based on TiO ₂ /In(OH) _x S _y /PbS/PEDOT:PSS/Au has been developed for photovoltaic applications. In this device, TiO ₂ , In(OH) _x S _y , PbS and PEDOT:PSS serve as electron conductor, buffer layer, absorber and hole conductor, respectively. Both buffer and absorber layers have been prepared by chemical bath deposition. For annealed In(OH) _x S _y , an optical band gap of 2.2 eV has been obtained and for PbS the bulk value is widened to about 0.85 eV due to the presence of oxide in the film composition. At present stage, solar cells with such configuration have reached up to about 1% efficiency with J _sc = 8 mA/cm ² and V _oc = 0.3 V. .