Boosted efficiency of conductive metal oxide-free pervoskite solar cells using poly(3-(4-methylamincarboxylbutyl)thiophene) buffer layers

Owing to low work functions of transparent anodes and poor contact issues at interfaces, p-i-n conductive metal oxide (CMO)-free perovskite solar cells (PVSCs) commonly suffer from a limited power conversion efficiency. Herein, we report an efficient CMO-free PVSC using poly(3-(4-methylamincarboxylbutyl)thiophene) (P3CT-N) modified poly(3,4-ethylenedioxylenethiophene):poly(styrenesulfonate) (PEDOT:PSS) anodes. The contact angle between PEDOT:PSS anodes and P3CT-N buffer layers tend to be 0 for an intimate contact. Meanwhile, the work function of the PEDOT:PSS anodes coated with P3CT-N is as high as -5.11 eV, which substantially accounted for the raised ability of hole transport. All the parameters (i.e. open-circuit voltage, short-circuit current density and fill factor) were improved simultaneously. As a result, the efficiency of the CMO-free solar cells was significantly improved from 4.63% to 13.13%. Our results indicate that P3CT-N is suitable to the highly conductive but hydrophobic PEDOT:PSS anodes for making high-efficiency CMO-free PVSCs.