LAUSR

To realize high-voltage organic photovoltaic (OPV) for indoor application and tandem solar cells, both electron-donor and acceptor in the active layer usually adopt wide-bandgap materials. However, the consequent small energy offsets may impede the dissociation of excitons, together with the inadequate light-harvesting, usually leading to the relatively low photocurrent. In this work, we utilize molecular structural modifications to improve the short-circuit current (JSC ) of the high-voltage OPV. With the classic non-fullerene acceptor (NFA), BTA3, as a benchmark, BTA3b contains the linear alkyl chains on the middle core, and JC14 further fuses thiophene ring on BTA unit. We deeply studied the effect of structural modification on broadening the photoelectric response and device performance by using a benzotriazole-based polymer J52-F as donor. The photovoltaic devices based o N J52-F: : BTA3b an D J52-F: : JC14 achieve wider external quantum efficiency (EQE) responses with band edges of 730 and 800 nm respectively, which are about 15 and 85 nm wider than that of the device based o N J52-F: : BTA3. The JSC of the BTA3b and JC14 are accordingly increased to 14.08 and 15.78 mA cm-2 respectively in comparison with BTA3 (11.56 mA cm-2 ). The smaller Urbach energy of 28.16 meV and higher electroluminescence efficiency guarante E J52-F: : JC14 a decreased energy loss (0.528 eV) and a high VOC of 1.07 V. Finally , J52-F: : JC14 combination achieves an increased PCE of 10.33% than that o F J52-F: : BTA3b (PCE = 9.81%) an D J52-F: : BTA3 (PCE = 9.04%). Overall, our research results indicate that subtle structure modification of non-fullerene acceptors, especially introducing fused ring, is a simple and effective strategy to extend the photoelectric response and achieve small energy loss, consequently boosting the JSC and ensuring a high VOC beyond 1.0 V. This article is protected by copyright. All rights reserved.