 Thin-film solar cells, TFSCs, are being explored as a sustainable energy source, but their efficiency has plateaued, leading to the development of new materials such as CD1-XCNX-T, CZT, and CD1-XMNX-T, CMT. These materials have been used in tandem photovoltaic cells, and both CZT and CMT-based PV cells were fabricated using vacuum evaporation method. The devices showed a power conversion efficiency of 6.67% and 6.11%, respectively, with low absorber layer thickness. Capacitance voltage measurements were used to determine the depletion layer width and dopant densities of both photovoltaic cells. Quantum efficiencies were measured to identify specific losses causing short-circuit current density deviation from its ideal value. The reproducibility of the devices was tested with an 8-12% deviation. This article was authored by Sibash Chander and Surya Contrapathy.