Flexible, hole transporting layer-free and stable CH 3 NH 3 PbI 3 /PC 61 BM planar heterojunction perovskite solar cells

Hole transporting layer (HTL)-free CH3NH3PbI3/PC61BM planar heterojunction perovskite solar cells were fabricated with the configuration of ITO/CH3NH3PbI3/PC61BM/Al. The devices present a remarkable power conversion efficiency (PCE) of 11.7% (12.5% best) under AM 1.5G 100 mW cm−2 illumination. Moreover, the HTL-free perovskite solar cells on flexible PET substrates are first demonstrated, achieving a power conversion efficiency of 9.7%. The element distribution in the HTL-free perovskite solar cell was further investigated. The results indicated that the PbI2 enriched near the PC61BM side for chlorobenzene treatment via the fast deposition crystallization method. Without using HTL on the ITO, the device is stable with comparison to that with poly(3,4-ethylenedioxylenethiophene): poly(styrene sulfonate) (PEDOT:PSS) as HTL. In addition, the fabricating time of the whole procedure from ITO substrate cleaning to device finishing fabrication only cost about 3 h for our mentioned devices, which is much more rapid than other structure devices containing other transporting layer. The high efficient and stable HTL-free CH3NH3PbI3/PC61BM planar heterojunction perovskite solar cells with the advantage of saving time and cost provide the potential for commercialization printing electronic devices.