Narrow-Bandgap Acceptors with Low Energetic Disorder Achieve over 21% Efficiency in Organic Solar Cells

• • Tao et al. report a PCE exceeding 21% in organic solar cells using narrow-bandgap acceptors with low energetic disorder, surpassing the previous ~20% ceiling; this directly reduces the levelized cost of energy (LCOE) by enabling higher power output per unit area, a critical metric for rooftop and building-integrated photovoltaics. • • Westbrook et al. demonstrate that solid-state packing controls exciton delocalization, with specific packing motifs reducing energetic disorder to below 50 meV; such low disorder suppresses non-radiative voltage losses, yielding Voc values above 0.90 V in devices with optical gaps near 1.3 eV, a key requirement for tandem cells. • • Jiang et al. show that photoluminescent delocalized excitons in donor polymers increase charge generation efficiency to over 90% (internal quantum efficiency) at low driving force (<0.1 eV), eliminating the need for large energy offsets and thus reducing thermalization losses that plague conventional donor:acceptor blends. • • Zhang et al. achieve binary OSCs with low energy loss (Eloss < 0.50 eV) via synergistic steric hindrance and chlorination, delivering PCEs above 18% with enhanced thermal stability (T80 > 1000 h at 85°C); this addresses the industrial bottleneck of insufficient operational lifetime under accelerated aging.