Donor-Acceptor Type Dopant-Free, Polymeric Hole Transport Material for Planar Perovskite Solar Cells (19.8%)

Organic-inorganic hybrid perovskite has led to the development of new solar cells with outstanding efficiency. In perovskite solar cells (PSCs), perovskite is sandwiched between a working electrode (fluorine-doped tin oxide) and a counter electrode (gold, Au). In order to transport charges and block opposite charges, charge transport layers are inserted between perovskite and the electrodes. In particular, a hole transport layer is important because it generally prevents perovskite from exposure to air. Therefore, it is necessary to investigate dopant-free and hydrophobic polymeric hole transport materials (HTMs). In this study, a novel polymeric HTM (PTEG) is synthesized by controlling the solubility using a tetraethylene glycol group. The planar-PSC employing PTEG exhibits an efficiency of 19.8% without any dopants, which corresponds to the highest value reported to date. This study offers a fundamental strategy for designing and synthesizing various polymeric HTMs.