High-performance hybrid perovskite solar cells with open circuit voltage dependence on hole-transporting materials

A series of conductive polymers, including poly(p-phenylene) (PPP), polythiophene (PT) and poly (4,4'-bis(N-carbazolyl)-1,1'-biphenyl) (PPN), were prepared via the electrochemical polymerization and their application as hole-transporting layer in CH3NH3PbI3 perovskite solar cells was explored. The open circuit voltage of the corresponding devices with an ITO/conductive-polymer/CH3NH3PbI3/C-60/BCP/Ag construction was correlated directly with the work functions of the conductive polymers that served as the hole-selective contact materials to the perovskite layer, as well as the recombination resistances of the devices. Highest open circuit voltage of 1.05 V was obtained on the devices with PPP that has a work function of 5.31 eV as the hole-transporting layer. Its power conversion efficiency reached about 16.5% with a high fill factor of 0.75, good open voltage of 1.03 V and short circuit current-density of 21.6 mA cm(-2). The results indicated that high conductive hole-transporting material with a work function about 5.3 eV is more compatible with this device construction to afford desired hole-selective contact. Furthermore, this simple, prompt, controllable and economic method to prepare hole-transporting materials would be favorable for large-scale production of hole-transporting layer for perovskite solar cells. (C) 2015 Elsevier Ltd. All rights reserved.