Orientation?Engineered Small?Molecule Semiconductors as Dopant?Free Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells

Crystallized p-type small-molecule semiconductors have great potential as an efficient and stable hole transporting materials (HTMs) for perovskite solar cells (PSCs) due to their relatively high mobility, good stability, tunable highest occupied molecular orbitals. Here, a thienoacene-based organic semiconductor, 2,9-diphenyldinaphtho[2,3-b:2?,3?-f]thieno[3,2-b]thiophene (DPh-DNTT), is thermally evaporated employed the dopant-free HTM that can be scaled up large-area fabrication. By controlling deposition temperature, orientation modulated into dominant face-on with ?–? stacking direction perpendicular substrate surface, maximizing out-of-plane carrier mobility. With engineered orientation, DPh-DNTT film shows improved mobility of 3.3 × 10?2 cm2 V?1 s?1, outperforming HTMs reported so far. Such orientation-reinforced contributes remarkable efficiency 20.2% CH3NH3PbI3 inverted PSCs enhanced stability. The results here provide insights engineering molecules PSCs.