Photovoltaics & Solar Cells

Solar photovoltaic technology is a method of converting light into electricity at the atomic level through the photoelectric effect. In this process, certain semiconductor materials absorb photons, or particles of sunlight, and release electrons. A photovoltaic cell, which produces electricity from visible light, absorbs the entire spectrum of light frequencies, not just visible light, converting solar radiation into useful energy. Photovoltaic and solar cell systems are safe, sustainable, and efficient sources of energy, widely used in applications ranging from electric vehicles (EVs) and solar roofs to water pumping and desalination systems. Photovoltaic cells typically utilize layered semiconductor materials in a PN junction configuration to convert light energy into electric current. The PN junction consists of a p-type semiconductor (electron acceptor) and an n-type semiconductor (electron donor). When sunlight strikes the n-type material, it dislodges an electron, generating a free electron and an electron-hole pair. The free electron is attracted to the p-type material, while the positively charged hole moves towards the n-type material. If a circuit is completed through electrodes, the free electron flows through the circuit, generating electricity until it recombines with the hole in the p-type material. The efficiency of photovoltaic systems depends on the type of solar cell technology and semiconductor materials used. Early solar cells were made from inorganic polycrystalline and single-crystalline materials. Significant progress has been made with advancements in organic electronics and materials. Organic solar cells are lightweight, flexible, and can be produced cost-effectively with high-performance polymeric donors, fullerene, and non-fullerene acceptors (NFAs), using low-temperature solution processing on transparent conductors like indium tin oxide (ITO) or fluorine-doped tin oxide (FTO). The development of organic hole-transport materials (HTMs) has enabled the creation of high-performance perovskite solar cells, which offer an alternative, more efficient method for harvesting solar energy. Perovskite solar cells typically use a hybrid inorganic-organic material as the light-harvesting layer and benefit from high conversion efficiency, low production costs, and simple manufacturing processes, making them the fastest-growing solar technology for commercial use. Lead halide perovskites, in particular, have the highest conversion efficiency, making them the most rapidly advancing solar cell technology.