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 hole mobility, good stability, and 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 and employed as the...