Modification of PCBM electron transport layer (ETL) by potassium iodide in inverted type perovskite solar cells

Abstract

Over the past decade, perovskite solar cells have garnered significant attention owing to their exceptional optoelectronic properties. The performance of perovskite solar cells is highly dependent on the efficient operation of both hole transport layers and electron transport layers, making the selection of cost-effective and compatible charge transport materials critically important. Phenyl-C61-butyric acid methyl ester (PCBM) is widely utilized as an electron transport layer (ETL) in perovskite solar cells; however, several limitations persist, including low electron mobility, challenges in the deposition of uniform and high-quality films, and considerable interfacial recombination losses. In this study, potassium iodide (KI) doping of PCBM was investigated to enhance the photovoltaic parameters of perovskite solar cells. The incorporation of KI was found to enhance photovoltaic performance by optimizing surface morphology. Characterization techniques such as space charge limited current (SCLC) measurements confirmed a decrease in trap-state density within the perovskite layer, thereby mitigating charge recombination and contributing to improved device efficiency.Graphical abstractDevice fabrication under ambient air