**1. Introduction**

Chalcogenide thin films have attracted a great deal of attention for decades because of several reasons such as earth abundancy, environmental friendly [1–3], excellent structural [4–6], electrical [7–9], and optical properties [10–12]. These materials could be employed in various applications such as solar cells [13–15], ultraviolet light emitters, laser devices [16], spin functional devices, gas sensors, transparent electronics, corrosion resistant coating [17], microelectronics [18], optics, magnetic and acoustic wave devices. Several deposition methods including chemical vapor deposition [19], physical vapor deposition [20], sputtering [21], SILAR, spray pyrolysis [22], chemical bath deposition [23–26], vacuum evaporation method [27], and electro deposition

method [28, 29] have been used to produce thin films. Generally, these deposition methods could be divided into physical method and chemical techniques. Researchers highlighted that the chemical deposition method has many advantages such as inexpensive, and convenient for large area deposition [30–32].

Supercapacitor has been considered as one of the potential energy storage systems. The redox electrochemical capacitors and the electrochemical double layer capacitor have been extensively investigated by many researchers. Researcher reported that transition metal oxide, conducting polymers, and metal oxide thin films have been tested in supercapacitors. The perovskite structure consisted of the crystal structure of calcium titanium oxide. This material showed high absorption coefficient with a sharp absorption edge. The organic-inorganic hybrid perovskites based solar cell was made from sandwiching a perovskite absorber layer between the electron transport layer and hole transport layer. The obtained solar cells showed some unique advantages such as low-temperature processes for all sub cells, compatibility with flexible and lightweight applications. The thin film-based sensor could be used to convert physical or chemical quantity into equivalent electrical for measurement. Sensor is critical in improving the reliability and efficiency of manufacturing operations by providing faster and more accurate feedback regarding product quality.

In this book chapter, thin film based solar cell, thin film based supercapacitor and thin film based sensor will be discussed. The properties of the obtained films were reported. Lastly, the advantages and limitations of these materials will be highlighted.
