Multiselenophene-Substituted Propeller-Shaped Trimeric Acceptor for Efficient Organic Solar Cells

The development of high-performance trimer acceptors (TMAs) for organic solar cells (OSCs) is often hampered by their blue-shifted absorption spectra. Consequently, to overcome this limitation and enhance device performance, we designed two propeller-shaped TMAs, TYSe-1 and TYSe-2, employing a multiselenophene strategy to achieve the desired redshift in absorption. In addition, side-chain isomerization was employed to tune the molecular packing and aggregation. The linear nonyl chains in TYSe-1 enabled tighter intermolecular stacking than the branched chains in TYSe-2, thus yielding an optimized blend morphology that enhanced exciton dissociation, charge transport, and charge extraction. Combined with its efficient absorption, TYSe-1-based OSCs achieved an outstanding short-circuit current density (JSC) value of 26.53 mA cm–2, ranking among the highest reported for TMA-based devices. Moreover, TYSe-1 exhibited higher electroluminescence quantum efficiency, leading to suppressed nonradiative recombination loss (ΔE3) and reduced overall energy loss. With an open-circuit voltage (VOC) value of approximately 0.857 V and an exceptional JSC value, TYSe-1-based OSCs attained a notable power conversion efficiency of 16.84%. These findings underscore the significant potential of the multiselenophene approach in designing red-shifted, high-performance TMA-based organic photovoltaics.