Energy loss within organic solar cells (OSCs) is undesirable as it reduces cell efficiency^1,2,3,4. In particular, non-radiative recombination loss³ and energetic disorder⁵, which are closely related to the tail states below the band edge and the overall photon energy loss, need to be minimized to improve cell performance. Here, we report how the use of a small-molecule acceptor with torsion-free molecular conformation can achieve a very low degree of energetic disorder and mitigate energy loss in OSCs. The resulting single-junction OSC has an energy loss due to non-radiative recombination of just 0.17 eV and a high power conversion efficiency of up to 16.54% (certified as 15.89% by the National Renewable Energy Laboratory). The findings take studies of organic photovoltaics deeper into a new regime, beyond the limits of energetic disorder and large energy offset for charge generation.

有机太阳能电池（OSC）内的能量损失不理想，因为它会降低电池效率^1,2,3,4。特别是非辐射重组损失³和高能障碍⁵与能带边缘以下的尾态和整个光子能量损失密切相关的，需要最小化以改善电池性能。在这里，我们报告如何使用具有无扭转分子构象的小分子受体可以实现极低的能量紊乱并减轻OSC中的能量损失。最终的单结OSC由于无辐射复合而导致的能量损失仅为0.17 eV，并且高达16.54％的高功率转换效率（由美国国家可再生能源实验室认证为15.89％）。这些发现将有机光伏的研究带入了新的领域，超越了高能紊乱和电荷产生的大量能量抵消的限制。