Stable and Low‐Cost Organic Photovoltaics Without Conjugated Donors

ABSTRACT Despite significant advances in power conversion efficiency (PCE) exceeding 20%, organic photovoltaics (OPVs) face industrialization challenges due to inherent stability issues associated with conventional organic donors and hole transport layers. Here, we employ an inorganic p‐type semiconductor copper(I) thiocyanate (CuSCN) as a multifunctional component concurrently serving as donor and hole transport layer. Combined with the non‐fullerene acceptor L8‐BO, the bulk heterojunction device achieves a champion PCE of 7.21%. More importantly, the CuSCN‐based devices exhibit exceptional thermal stability, maintaining 80% of their initial efficiency ( T 80 ) for nearly 400 h at 85°C, far exceeding the T 80 of 3 to 33 h for OPVs based on conventional all‐organic active layers. Moreover, under ISOS‐L‐3 protocol (maximum power point tracking under 100 mW cm −2 illumination, 65°C, 50% relative humidity), the devices exhibit outstanding operational durability, sustaining approximately 50% of their initial efficiency after 900 h, in stark contrast to the rapid degradation observed in D18:L8‐BO and PM6:L8‐BO reference systems, which retain only 15% and 19%, respectively. This work underscores the potential of CuSCN in enabling efficient, durable, and industrially viable OPVs.