A New 1,3,4-Oxadiazole-Based Hole-Transport Material for Efficient CH3 NH3 PbBr3 Perovskite Solar Cells

A new hole-transport material (HTM) based on the 1,3,4-oxadiazole moiety (H1) was prepared through a single-step synthetic pathway starting from commercially available products. Thanks to a deep HOMO level, H1 was used as HTM in CH3 NH3 PbBr3 perovskite solar cells yielding an efficiency of 5.8%. The reference HTM (Spiro-OMeTAD), under the same testing conditions, furnished a lower efficiency of 5.1%. Steady-state and time-resolved photoluminescence of the thin films showed good charge-extraction dynamics for H1 devices. In addition, H1 shows a large thermal stability and completely amorphous behavior (as evaluated by thermal gravimetric analysis and differential scanning calorimetry).