Thermally-stable and highly-efficient bi-layered NiOx-based inverted planar perovskite solar cells by employing a p-type organic semiconductor

Abstract

Nickel oxide (NiOx) is one of the most promising inorganic hole transport layers for perovskite solar cells (PSCs) due to its low cost, high hole mobility, and superior stability. However, the mismatched energy level and undesirable chemical reaction at the NiOx/perovskite interface limit the performance of NiOx-based PSCs. Herein, a p-type semiconductor TPA-BA is explored to modify the NiOx/perovskite interface and form an intermediate hole transport layer (HTL) between NiOx and perovskite for efficient and efficient stable PSCs. This molecule comprises triphenylamine and carboxyl function groups, which can be anchored on the NiOx surface and facilitate the hole transfer between the perovskite and NiOx layer by minimizing the interfacial band energy offset. Furthermore, the bi-layered NiOx HTL exhibited reduced chemical reactivity at NiOx/perovskite interface, which would otherwise lead to detrimental perovskite degradation. Thus, a champion PSC device with an open-circuit voltage value up to 1.15 V and a power conversion efficiency of 22.25% was demonstrated-a high value for NiOx-based PSCs. More importantly, the intermediated HTL modified PSCs exhibit significantly improved device stability compared with un-modified PSCs, retaining over 90 % of their initial efficiencies after 1000-h continuous operation under 1 sun illumination and thermal aging at 85 °C respectively. This work renders the promise of TPA-BA as the intermediated HTL in between p-type metal oxide and perovskite for optoelectronic applications.