We developed three narrow band-gap polymer acceptors PF2-DTC, PF2-DTSi, and PF2-DTGe with different bridging atoms (i.e., C, Si, and Ge). Studies found that such different bridging atoms significantly affect the crystallinity, extinction coefficient, electron mobility of the polymer acceptors, and the morphology and mechanical robustness of related active layers. In all-polymer solar cells (all-PSCs), these polymer acceptors achieved high power conversion efficiencies (PCEs) over 8.0%, while PF2-DTSi obtained the highest PCE of 10.77% due to its improved exciton dissociation, charge transport, and optimized morphology. Moreover, the PF2-DTSi-based active layer showed excellent mechanical robustness with a high toughness value of 9.3 MJ m⁻³ and a large elongation at a break of 8.6%, which is a great advantage for the practical applications of flexible devices. As a result, the PF2-DTSi-based flexible all-PSC retained >90% of its initial PCE (6.37%) after bending and relaxing 1,200 times at a bending radius of ∼4 mm.

我们开发了三种具有不同桥接原子（即C，Si和Ge）的窄带隙聚合物受体PF2-DTC，PF2-DTSi和PF2-DTGe。研究发现，这种不同的桥连原子会显着影响聚合物受体的结晶度，消光系数，电子迁移率以及相关活性层的形态和机械强度。在全聚合物太阳能电池（all-PSC）中，这些聚合物受体实现了8.0％以上的高功率转换效率（PCE），而PF2-DTSi由于其激子解离，电荷传输和优化的改进而获得了10.77％的最高PCE。形态学。此外，基于PF2-DTSi的活性层表现出优异的机械强度，并且具有9.3 MJ m ^-3的高韧性值断裂伸长率大，为8.6％，这对于柔性设备的实际应用是一个很大的优势。结果，在以〜4 mm的弯曲半径弯曲并松弛1200次后，基于PF2-DTSi的柔性全PSC保留了其初始PCE的90％以上（6.37％）。