N-Bromosuccinimide as a p-type dopant for a Spiro-OMeTAD hole transport material to enhance the performance of perovskite solar cells

Low cost N-bromosuccinimide (NBS) was applied as an effective p-type dopant in 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9-spirobifluorene (Spiro-OMeTAD), an important hole transport material (HTM) for perovskite solar cells (PSCs).