Xia Yiqiu, Wang Chen, Dong Biao, Wang Ge, Chen Yi, MacKenzie Roderick C I, Dong Wei, Ruan Shengping, Liu Yizhan, Wen Shanpeng
State Key Laboratory on Integrated Optoelectronics and College of Electronic Science & Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China.
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
ACS Appl Mater Interfaces. 2021 Mar 31;13(12):14423-14432. doi: 10.1021/acsami.0c23087. Epub 2021 Mar 18.
There has been a growing interest in the development of efficient flexible organic solar cells (OSCs) due to their unique capacity to provide energy sources for flexible electronics. To this end, it is required to design a compatible interlayer with low processing temperature and high electronic quality. In this work, we present that the electronic quality of the ZnO interlayer fabricated from a low-temperature (130 °C) sol-gel method can be significantly improved by doping an organic small molecule, TPT-S. The doped TPT-S, on the one hand, passivates uncoordinated Zn-related defects by forming N-Zn bonds. On the other hand, photoinduced charge transfer from TPT-S to ZnO is confirmed, which further fills up electron-deficient trap states. This renders ZnO improved electron transport capability and reduced charge recombination. By illuminating devices with square light pulses of varying intensities, we also reveal that an unfavorable charge trapping/detrapping process observed in low-temperature-processed devices is significantly inhibited after TPT-S doping. OSCs based on PBDB-T-2F:IT-4F with ZnO:TPT-S being the cathode interlayer yield efficiencies of 12.62 and 11.33% on rigid and flexible substrates, respectively. These observations convey the practicality of such hybrid ZnO in high-performance flexible devices.
由于高效柔性有机太阳能电池（OSCs）能够为柔性电子产品提供能源，其开发受到了越来越多的关注。为此，需要设计一种具有低加工温度和高电子质量的兼容中间层。在这项工作中，我们展示了通过掺杂有机小分子TPT-S，可以显著提高由低温（130°C）溶胶-凝胶法制备的ZnO中间层的电子质量。一方面，掺杂的TPT-S通过形成N-Zn键钝化未配位的Zn相关缺陷。另一方面，证实了从TPT-S到ZnO的光致电荷转移，这进一步填充了电子缺陷陷阱态。这使得ZnO的电子传输能力得到提高，电荷复合减少。通过用不同强度的方形光脉冲照射器件，我们还发现，在TPT-S掺杂后，在低温处理的器件中观察到的不利的电荷俘获/去俘获过程得到了显著抑制。以PBDB-T-2F:IT-4F为基础、以ZnO:TPT-S作为阴极中间层的OSCs在刚性和柔性基板上的效率分别为12.62%和11.33%。这些观察结果表明了这种混合ZnO在高性能柔性器件中的实用性。
