Molybdenum-Oxide-Modified PEDOT:PSS as Efficient Hole Transport Layer in Perovskite Solar Cells

Over the last ten years, there has been a remarkable enhancement in the power conversion efficiency (PCE) of perovskite solar cells (PSCs), with poly (3,4-ethylenedioxythiohene):poly (styrenesulfonate) (PEDOT:PSS) emerging as a prevalent choice for the hole transport layer (HTL). Nevertheless, the evolution of the widely utilized PEDOT:PSS HTL has not kept pace with the swift advancements in PSC technology, attributed to its suboptimal electrical conductivity, acidic nature, and inadequate electron-blocking performance. This study presents a novel approach to enhance the HTL by introducing molybdenum oxide (MoO₃) into the PEDOT:PSS, leveraging the conductivity and solution processing compatibility of MoO₃. Two methods for MoO₃ integration were explored: an ammonium molybdate tetrahydrate (AMT) precursor and the direct addition of MoO₃ nanoparticles. The carrier dynamics of PSCs modified by MoO₃ are significantly optimized. Therefore, the PCE of the device modified by AMT and molybdenum oxide is increased to 18.23 and 19.64%, respectively, and the stability of the device is also improved. This study emphasizes the potential of MoO₃ in contributing to the development of more efficient and stable PSCs.