Stable and Low-Cost Organic Photovoltaics Without Conjugated Donors

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 (T₈₀) for nearly 400 h at 85°C, far exceeding the T₈₀ 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.