Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 University Rood, Hsinchu 30010, Taiwan.
Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, 1001 University Rood, Hsinchu 30010, Taiwan.
ACS Appl Mater Interfaces. 2023 May 24;15(20):24658-24669. doi: 10.1021/acsami.3c02966. Epub 2023 May 15.
Terminal acceptor atoms and side-chain functionalization play a vital role in the construction of efficient nonfullerene small-molecule acceptors (NF-SMAs) for AM1.5G/indoor organic photovoltaic (OPV) applications. In this work, we report three dithienosilicon-bridged carbazole-based (DTSiC) ladder-type (A-DD'D-A) NF-SMAs for AM1.5G/indoor OPVs. First, we synthesize DTSiC-4F and DTSiC-2M, which are composed of a fused DTSiC-based central core with difluorinated 1,1-dicyanomethylene-3-indanone (2F-IC) and methylated IC (M-IC) end groups, respectively. Then, alkoxy chains are introduced in the fused carbazole backbone of DTSiC-4F to form DTSiCODe-4F. From solution to film absorption, DTSiC-4F exhibits a bathochromic shift with strong π-π interactions, which improves the short-circuit current density () and the fill factor (FF). On the other hand, DTSiC-2M and DTSiCODe-4F display up-shifting lowest unoccupied molecular orbital (LUMO) energy levels, which enhances the open-circuit voltage (). As a result, under both AM1.5G/indoor conditions, the devices based on PM7:DTSiC-4F, PM7:DTSiC-2M, and PM7:DTSiCOCe-4F show power conversion efficiencies (PCEs) of 13.13/21.80%, 8.62/20.02, and 9.41/20.56%, respectively. Furthermore, the addition of a third component to the active layer of binary devices is also a simple and efficient strategy to achieve higher photovoltaic efficiencies. Therefore, the conjugated polymer donor PTO2 is introduced into the PM7:DTSiC-4F active layer because of the hypsochromically shifted complementary absorption, deep highest occupied molecular orbital (HOMO) energy level, good miscibility with PM7 and DTSiC-4F, and optimal film morphology. The resulting ternary OSC device based on PTO2:PM7:DTSiC-4F can improve exciton generation, phase separation, charge transport, and charge extraction. As a consequence, the PTO2:PM7:DTSiC-4F-based ternary device achieves an outstanding PCE of 13.33/25.70% under AM1.5G/indoor conditions. As far as we know, the obtained PCE results under indoor conditions are one of the best binary/ternary-based systems processed from eco-friendly solvents.
端基接受体原子和侧链官能团在构建高效的非富勒烯小分子受体（NF-SMA）方面发挥着重要作用，可用于 AM1.5G/室内有机光伏（OPV）应用。在这项工作中，我们报告了三种基于二噻吩硅桥联咔唑的（DTSiC）梯形（A-DD'D-A）NF-SMA，用于 AM1.5G/室内 OPV。首先，我们合成了 DTSiC-4F 和 DTSiC-2M，它们分别由一个融合的 DTSiC 为中心核，带有二氟代 1,1-二氰基乙烯-3-茚满酮（2F-IC）和甲基化 IC（M-IC）端基。然后，在 DTSiC-4F 的融合咔唑主链中引入烷氧基链，形成 DTSiCODe-4F。从溶液到薄膜吸收，DTSiC-4F 表现出红移的强烈π-π相互作用，提高了短路电流密度（Jsc）和填充因子（FF）。另一方面，DTSiC-2M 和 DTSiCODe-4F 显示出向上移动的最低未占据分子轨道（LUMO）能级，从而提高了开路电压（Voc）。因此，在 AM1.5G/室内条件下，基于 PM7:DTSiC-4F、PM7:DTSiC-2M 和 PM7:DTSiCOCe-4F 的器件分别显示出 13.13%/21.80%、8.62%/20.02%和 9.41%/20.56%的功率转换效率（PCE）。此外，在二元器件的活性层中添加第三组分也是实现更高光伏效率的一种简单而有效的策略。因此，由于互补吸收的红移、更深的最高占据分子轨道（HOMO）能级、与 PM7 和 DTSiC-4F 的良好混溶性以及最佳的薄膜形貌，将共轭聚合物给体 PTO2 引入 PM7:DTSiC-4F 活性层中。基于 PTO2:PM7:DTSiC-4F 的三元 OSC 器件可以提高激子产生、相分离、电荷输运和电荷提取效率。因此，基于 PTO2:PM7:DTSiC-4F 的三元器件在 AM1.5G/室内条件下实现了 13.33%/25.70%的出色 PCE。据我们所知，在室内条件下获得的 PCE 结果是使用环保溶剂处理的二元/三元基系统中最好的结果之一。
