**Abstract**

Chalcogenide thin films have attracted a great deal of attention for decades because of their unique properties. The recent developments on thin film-based supercapacitor applications were reported. As a result of sustained efforts, the experimental findings revealed remarkable properties with enhanced fabrication methods. The properties of perovskite solar cells were discussed in terms of crystal structure and phase transition, electronic structure, optical properties, and electrical properties. Perovskite solar cell has gained attention due to its high absorption coefficient with a sharp absorption edge, high photoluminescence quantum yield, long charge carrier diffusion lengths, large mobility, high defect tolerance, and low surface recombination velocity. The thin film-based gas sensors are used for equally the identification and quantification of gases, and hence should be both selective and sensitive to a required target gas in a mixture of gases. Metal chalcogenide materials are considered excellent absorber materials in photovoltaic cell applications. These materials exhibited excellent absorption coefficient and suitable band gap value to absorb the maximum number of photons from sun radiation. The photovoltaic parameters were strongly dependent on various experimental conditions.

**Keywords:** thin films, semiconductor, band gap, solar cells, sensor, chalcogenide materials, supercapacitor, power conversion efficiency
