A study on solution-processable tetrabenzomonoazaporphyrin hole transport material for pervoskite solar cells

Quang-Duy Dao, Akihiko Fujii, Ryotaro Tsuji and Masanori Ozaki

Abstract

We demonstrate optical and electronic properties and structure of an efficient hole transporting material (HTM), soluble non-peripherally substituted octahexyl tetrabenzomonoasaporphyrin (C6TBMAPH₂), for perovskite solar cells (PSCs). X-ray diffraction patterns of C6TBMAPH₂ thin film with two peaks at around 4.6° and 4.9° indicate that the symmetry of columns is likely to be 2-dimensional rectangular lattice and stacking period of molecules along columnar axis may be disordered. The absorption spectra of C6TBMAPH₂ exhibit the two predominated bands at around 400 and 650 nm, which correspond to the B and Q bands, respectively. Furthermore, the electronic band structure of C6TBMAPH₂, was calculated with highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of −5.0 and −3.3 eV, respectively. All results suggest that C6TBMAPH₂ could be one potential HTM to extract hole and block electron from the absorber to the back electrode. Finally, an efficient solid-state, thin-film PSC utilising C6TBMAPH₂ HTM is fabricated with the best PCEs of 4.9 and 5.6% under forward and reverse bias scans, respectively.