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

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.