Unsymmetrical and Symmetrical Zn(II) Phthalocyanines as Hole-Transporting Materials for Perovskite Solar Cells
journal contributionposted on 31.05.2018, 00:00 by Yi Zhang, Sanghyun Paek, Maxence Urbani, María Medel, Iwan Zimmermann, Kyung Taek Cho, Mine Ince, Mohammad Khaja Nazeeruddin, Tomás Torres
An unsymmetrical zinc phthalocyanine with one carboxyl and three tert-butyl groups (TT1) and a symmetrical zinc phthalocyanine with four tert-butyl groups (TT0) are employed as hole-transporting materials (HTMs) in mixed-ion perovskite [HC(NH2)2]0.1(CH3NH3)0.9PbI3 solar cells. The optical and electrochemical data of TT1 and TT0 exhibit appropriate energy levels for efficient interfacial charge transfer with the perovskite. The perovskite solar cells with TT1 show 16 ± 1 mA/cm2 photocurrent and 0.95 ± 0.07 V open circuit voltage resulting in 13.0 ± 0.7% power conversion efficiency at 1 sun. Under the same conditions, the symmetric phthalocyanine TT0 shows 20.2 mA/cm2 photocurrent and 1.05 V open circuit voltage resulting in 14% power conversion efficiency.