Molecular engineering to enhance perovskite solar cell performance: Incorporation of benzothiadiazole as core unit for low cost hole transport materials

Through molecular engineering, a benzothiadiazole unit is incorporated as the core structure to generate a new hole transport material JY5. Cyclic voltammetry measurement suggests matched energy level of JY5 with the perovskite materials. TGA and DSC show excellent thermal stability of JY5. Hole mobility and PL decay experiments indicate good hole transport ability in JY5. As a result, perovskite solar cells utilizing JY5 as HTM outperforms the biphenyl centered analogue, and a champion efficiency of 16.87% was achieved among the HTMs studied in this work, with short-circuit current (Jsc) of 21.06 mA cm−2, open-circuit voltage (Voc) of 1.06 V, and fill factor (FF) of 0.76. The high efficiency as well as low costs make it potential alternative to the highly cost Spiro-OMeTAD.