Efficient Nonfullerene Organic Solar Cells with Small Driving Forces for Both Hole and Electron Transfer
Efficient Nonfullerene Organic Solar Cells with Small Driving Forces for Both Hole and Electron Transfer
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DOI：
10.1002/adma.201804215
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发表时间：
2018-11-01
影响因子：
29.4
通讯作者：
Yan, He
中科院分区：
文献类型：
--
作者：
Chen, Shangshang;Wang, Yuming;Yan, He
最先进的有机太阳能电池（OSC）与其无机和钙钛矿对应物相比通常遭受大的电压损失（V损失）。有一些成功的尝试通过减少供体和受体材料之间的能量偏移来减少V-损失，并且OSC社区已经证明了在供体和受体之间具有小的最高占据分子轨道（HOMO）偏移或可忽略的最低未占据分子轨道（LUMO）偏移的有效系统。然而，基于具有小HOMO和LUMO偏移的供体/受体系统的高效OSC尚未同时得到证实。在这项工作中，一个有效的非富勒烯OSC的基础上命名为PffBT 2 T-TT和一个小分子受体（O-IDTBR），具有相同的带隙和接近的能级的供体聚合物的报告。共混物的傅里叶变换光电流光谱外量子效率（FTPS-EQE）光谱与纯PffBT 2 T-TT和O-IDTBR的光谱重叠，表明空穴和电子转移的驱动力都很小。同时，OSC表现出近似1 × 10（-4）的高电致发光量子效率（EQE（EL）），这导致0.24 V的显著最小化的非辐射V损耗。尽管驱动力小且V损耗低，但仍然可以实现67%的最大EQE和10.4%的高功率转换效率。
State-of-the-art organic solar cells (OSCs) typically suffer from large voltage loss (V-loss) compared to their inorganic and perovskite counterparts. There are some successful attempts to reduce the V-loss by decreasing the energy offsets between the donor and acceptor materials, and the OSC community has demonstrated efficient systems with either small highest occupied molecular orbital (HOMO) offset or negligible lowest unoccupied molecular orbital (LUMO) offset between donors and acceptors. However, efficient OSCs based on a donor/acceptor system with both small HOMO and LUMO offsets have not been demonstrated simultaneously. In this work, an efficient nonfullerene OSC is reported based on a donor polymer named PffBT2T-TT and a small-molecular acceptor (O-IDTBR), which have identical bandgaps and close energy levels. The Fourier-transform photocurrent spectroscopy external quantum efficiency (FTPS-EQE) spectrum of the blend overlaps with those of neat PffBT2T-TT and O-IDTBR, indicating the small driving forces for both hole and electron transfer. Meanwhile, the OSCs exhibit a high electroluminescence quantum efficiency (EQE(EL)) of approximate to 1 x 10(-4), which leads to a significantly minimized nonradiative V-loss of 0.24 V. Despite the small driving forces and a low V-loss, a maximum EQE of 67% and a high power conversion efficiency of 10.4% can still be achieved.