Thermally stable dopant-free soluble phthalocyanines as hole transporting materials for Perovskite solar cells

Abstract

In enhancing the durability and photovoltaic performance of Perovskite solar cells, Hole transport Materials (HTMs) play the key role. In search of new HTMs, in this work, we have designed, synthesized and characterized 3,4,5 trimethoxy phenoxy substituent free-base soluble phthalocyanine (H2-TmPc) along with their metallo derivates with Cu(II) (Cu-TmPc) and Zn(II) (Zn-TmPc) derivatives and applied them as HTMs for PSC. All three HTMs were characterized by optical, electrochemical, thermal and impedance studies. Absorption spectra in chlorobenzene revealed two Q bands and a soret band whereas metallo derivatives showed a single Q and soret band. Electrochemical studies revealed that these HTMs are capable of extracting holes from the Perovskite layer. Impedance studies showed that Cu-TmPc showed high specific conductance of 1.78× 10[Formula: see text] when compared to other derivatives. Based on these data PSCs were fabricated with these Pc series as HTMs and SnO2 as ETL layer and noticed that Cu-TmPc gave a power conversion efficiency of 5.7%.