Antioxidant induced bulk passivation for efficient and stable hole transport layer-free carbon electrode perovskite solar cells

Defect passivation is one of the important strategies to improve the efficiency and stability of perovskite solar cells. In this work, 2,6-di–tert–butyl–4-methylphenol(BHT) as antioxidant was introduced into the perovskite precursor solution to improve the quality of the prepared perovskite films, so that these films performed a larger and uniform grain size. Moreover, the-OH functional group in BHT interacts with I-,thus reducing the density of defect states and inhibiting the non-radiative recombination. The presence of hydrophobic groups in BHT protects the film from moisture erosion and improves the long-term stability of PSCs devices. The maximum photoelectric conversion efficiency of the constructed ITO/SnO2/BHTMAPbI3/Carbon device is 16.88%, and the unpackaged cell maintains the initial efficiency of 99.3% after698 h of storage under the environmental condition of 30% humidity. This work provides an efficient approach to improve the performance of printable hole transport layer-free carbon electrode perovskite solar cells.