Enhancing the performance and stability of organometal halide perovskite by using a feasible and economical interface material

Abstract

Organometal halide perovskites (OHPs) are one of the viable options for solar absorber materials because their power conversion efficiencies are getting better and better over time. In the conventional n-i-p-based configuration, TiO₂ has been widely used as an electron transport layer (ETL). However, a number of constraints, such as low electron mobility and a mismatched band alignment with perovskite, restrict future advances in solar performance and device environmental stability. As a result, SnO₂ has garnered a lot of interest as a potential replacement due to the comparatively low manufacturing temperature, better electron mobility and appropriate energy alignment w.r.t perovskite. In this experimental work, the primary emphasis was placed on enhancing the efficiency as well as the stability of OHPs by performing interface engineering at the ETL (SnO₂)/perovskite interface. We improved the surface quality of the SnO₂ ETL layer by using a material called 8-Hydroxyquinoline, which was quite inexpensive, and we prepared a favourable plane for the deposition of perovskite. Remarkably, the proposed surface modification material made the SnO₂ layer easier to wet and impacted the growth of perovskite grains. This made the perovskite layer more compact and smooth. Our experimental findings imply that the OHPs’ enhanced charge recombination resistance and decreased charge transfer resistance are caused by effective defect passivation at the junction of the SnO₂ and perovskite films, as well as a decrease in recombination due to unwanted trap states. The fabricated cell produced a power conversion efficiency (PCE) of 20.42%, higher than a PCE of 17.9% obtained for a device without surface modification. The proposed material for changing the surface also made OHPs more stable by reducing the surface paths for the reaction with humidity and reducing the amount of extra PbI₂ in the perovskite layer. Various research groups have investigated the modification of SnO₂ ETL using interfacial engineering methods and have contributed to enhancing OHPs’ solar performance and device stability.