Ultra-stable all-inorganic silver bismuth sulfide colloidal nanocrystal photovoltaics using pin type architecture

Silver bismuth sulfide (AgBiS2) colloidal nanocrystals (NCs) have emerged as an environmentally friendly light absorber for next-generation photovoltaics. Classical AgBiS2 NC photovoltaics with nip-architecture have been mandated to use a combination of polymer and molybdenum oxide as a hole transport layer (HTL), which are vulnerable to oxygen, heat and water. In this work, we develop all-inorganic AgBiS2 NC photovoltaics with pin-architecture, serving a nickel oxide (NiO) as HTL. We also employ a cascade-energy-level alignment by introducing 3-mercaptopropionic acid-treated AgBiS2 NC layer, enabling enhanced hole collection with minimized interfacial recombination. As a result, the pin type AgBiS2 NC photovoltaics demonstrate a power conversion efficiency of 5.59% as well as excellent stability even under extreme conditions such as heat and water exposures, attributed to superior chemical robustness of the inorganic HTL. This work is the first report on AgBiS2 NC device with all-inorganic components and achieves the highest device efficiency in pin type AgBiS2 NC photovoltaics.