Received: 16-01-2024 Revised: 12-02-2024 Accepted: 07-03-2024 1054 Volume 48 Issue 1 (March 2024) https://powertechjournal.com Effect of CdS on the Electrical Conductivity of Polyvinyl Alcohol (PVA) and Potassium Iodide (KI) thin films Ashish Raj 1 , Pavan Kumar Singh 1 , S P Pandey 1,2,* , Amit Saxena 3 , and Bhaskar Bhattacahrya 4 1 Department of Physics, Teerthanker Mahaveer University, Moradabad, UP, INDIA 2 Department of Applied Sciences, Delhi Technical Campus, Greater Noida (U.P.) INDIA 3 Department of Physics, SVIS, Shri Vaishnav Vidyapeeth Vishwavidyalaya, Indore, MP INDIA 4 Department of Physics, MMV, Banaras Hindu University, Varanasi, UP INDIA *Corresponding Author Abstract: In the past two decades, solid polymer electrolytes (SPEs) have attracted attention as a platform for electrochemical devices. Here polymer-based electrolytes have the advantage that they can be grown in a thin film, plus they are leak-proof. In the present work, we have used PVA:KI as the host polymer–salt complex with a composition of 85:15. Further, this PVA:KI complex dispersed with different wt% of CdS. Standard solution cast techniques have been used for thin film preparation. All prepared samples are characterized to study conductivity and structural changes. A maximum ionic conductivity of 2.47 X 10-7 S/cm was observed for 9wt% of CdS. Also, the band gap of these films was calculated and found to be between 2.4 to 2.9 eV. Also, the concentration and mobility of charge carriers were calculated to explain the change in conductivity pattern. This calculation was performed with the Schutt & Gerdes model. It is observed that the conductivity pattern mainly follows the concentration of charge carriers. 1. Introduction: Energy requirements and production are a challenge in the present scenario. Because a significant percentage of energy requirements are generated from conventional energy sources, including coal, petroleum, etc., but all these traditional energy sources are getting exhausted very fast [1]. An alternative solution to this problem is to choose some sustainable energy sources, where solar and wind power are the best examples. But there is a limit to these energy sources, which is the continuity of the energy supply. As we know, solar energy can only be generated for 8 - 10 hours unless the intensity of sunlight is high enough. And similar limits can be observed with other natural sources of energy [2]. Now here, the concept of energy storage can solve this limitation. Here it becomes essential to discuss the details of energy