LAUSR

Hole transporting layers (HTLs) play a crucial role in realization of efficient and stable perovskite solar cells (PSCs). Copper Phthalocyanine (CuPc) is one of the promising HTLs owing to its thermal stability and favorable band alignment with perovskite absorber. However, the power conversion efficiency (PCE) of PSCs with CuPc HTL is still lag behind highly efficient solar cells. Herein, a p-type F4-TCNQ is employed as an interlayer between the perovskite and CuPc HTL in all vacuum deposited PSCs. The F4-TCNQ interlayer improves the conductivity of both MAPbI3 and CuPc, reduces the shunt pathway and facilitates an efficient photoexcited holes transfer from the valance band of the MAPbI3 to LUMO of the F4-TCNQ. Consequently, a best solar cell device with F4-TCNQ interlayer achieved the PCE of 13.03% with a remarkable improvement in fill factor. Moreover, the devices showed superior stability against thermal stress at 85 ˚C over 250 hours and retained ~95% of its initial efficiency. This work demonstrates a significant step towards all vacuum deposited perovskite solar cells with high thermal stability.