Boosting efficiency and stability of perovskite solar cells via integrating engineered Li/Na-ferrite-based inorganic charge transport layers: a combined experimental and theoretical study

Organic–inorganic hybrid perovskite solar cells (PSCs) have made significant progress in achieving record-high efficiency in the past few years. However, the basic problem for commercialization is the interplay between high efficiency, scalable manufacturing, and chemical stability of the perovskite solar cell. Most efficient PSCs rely on Spiro-OMeTAD-based organic hole transporting layer (OHTL) which suffers from chemical instability, expensive material cost, and low durability. Herein, we demonstrate novel Li/Na-ferrite (LiFeO 2 /NaFeO 2 )-based inorganic hole transporting layers (IHTLs) as a potential replacement for Spiro-OMeTAD OHTL, leading to optimized PSCs with high efficiency and long-term chemical stability. The solar cell has been fabricated using the spin coating technique. The performance parameter of the device has been probed by investigating structural, optical, electrical, and photoconversion efficiency as well as simulation of the solar cell. PSCs using Li and Na-ferrite as IHTLs exhibited power conversion efficiency (PCE) ~ 17.5% and ~ 17.1%, respectively, which surpassed the overall performance of Spiro-OMeTAD-based PSC that exhibited PCE ~ 14.4%. The experimental and theoretical studies confirm the stabilized interfacial effect of Li/Na-ferrite IHTLs that strongly controls the crystallization of the perovskite films, charge carrier transport, and trap density, which leads to reduce non-radiative charge recombination losses and improved device stability for long-term operation. Our work highlights the significance of ferrite-based IHTLs as promising candidates for future efficient and stable perovskite solar cells. Graphical Abstract