Citation: Bist, A.; Pant, B.; Ojha, G.P.; Acharya, J.; Park, M.; Saud, P.S. Novel Materials in Perovskite Solar Cells: Efficiency, Stability, and Future Perspectives. Nanomaterials 2023, 13, 1724. https://doi.org/10.3390/ nano13111724 Academic Editors: Wolfgang Heiss and Elias Stathatos Received: 29 March 2023 Revised: 16 May 2023 Accepted: 17 May 2023 Published: 24 May 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). nanomaterials Review Novel Materials in Perovskite Solar Cells: Efficiency, Stability, and Future Perspectives Anup Bist 1 , Bishweshwar Pant 2,3,4, * , Gunendra Prasad Ojha 2,3,4 , Jiwan Acharya 2,3,4 , Mira Park 2,3,4, * and Prem Singh Saud 1, * 1 Department of Chemistry, Kailali Multiple Campus, Farwestern University, Mahendranagar 10400, Nepal 2 Carbon Composite Energy Nanomaterials Research Center, Woosuk University, Wanju 55338, Republic of Korea 3 Woosuk Institute of Smart Convergence Life Care (WSCLC), Woosuk University, Wanju 55338, Republic of Korea 4 Department of Automotive Engineering, Woosuk University, Wanju 55338, Republic of Korea * Correspondence: bisup@woosuk.ac.kr (B.P.); wonderfulmira@woosuk.ac.kr (M.P.); premsingh@fwu.edu.np (P.S.S.) Abstract: Solar energy is regarded as the finest clean and green energy generation method to replace fossil fuel-based energy and repair environmental harm. The more expensive manufacturing pro- cesses and procedures required to extract the silicon utilized in silicon solar cells may limit their production and general use. To overcome the barriers of silicon, a new energy-harvesting solar cell called perovskite has been gaining widespread attention around the world. The perovskites are scalable, flexible, cost-efficient, environmentally benign, and easy to fabricate. Through this review, readers may obtain an idea about the different generations of solar cells and their comparative advantages and disadvantages, working mechanisms, energy alignment of the various materials, and stability achieved by applying variable temperature, passivation, and deposition methods. Fur- thermore, it also provides information on novel materials such as carbonaceous, polymeric, and nanomaterials that have been employed in perovskite solar in terms of the different ratios of doping and composite and their optical, electrical, plasmonic, morphological, and crystallinity properties in terms of comparative solar parameters. In addition, information on current trends and future commercialization possibilities of perovskite solar have been briefly discussed based on reported data by other researchers. Keywords: perovskite solar cell (PSC); efficiency; stability; TiO 2 NPs 1. Introduction 1.1. Perovskite Solar Cells Energy demand is rising dramatically every day as the human population increases. As a result, the most widely used energy sources, such as coal, oil, diesel, and petroleum, are on the verge of becoming extinct. On the other hand, the emission of pollutants from the combustion of fossil fuels is the major cause of global warming. Therefore, it is eagerly required to promote renewable energy. The sources of renewable energy, such as solar, wind, tidal, geothermal, biomass, and hydrological energy, could replace fossil fuels to meet the world’s energy needs. Among them, solar energy is the most important due to its resource-free and zero-pollution. Since the invention of solar energy, silicon- based solar cells have been the only ones to be commercially successful. Unfortunately, it suffers from high costs, complex fabrication processes, and toxic byproducts. Therefore, other solar technologies, including cadmium telluride (CdTe), copper-Indium gallium diselenide (CIGS), dye-sensitized solar cells (DSSC), perovskite (PSC), and organic solar cells, are currently being researched and developed [1]. Among them, using perovskite semiconductor materials in solar systems has gained considerable focus to tackle the issues associated with the use of silicon materials in solar cells. Russian mineralogist L.A. Perovski developed the idea of perovskite [1,2]. This idea has defined the ABX 3 crystal’s Nanomaterials 2023, 13, 1724. https://doi.org/10.3390/nano13111724 https://www.mdpi.com/journal/nanomaterials