Li Congqi, Yao Guo, Gu Xiaobin, Lv Jikai, Hou Yuqi, Lin Qijie, Yu Na, Abbasi Misbah Sehar, Zhang Xin, Zhang Jianqi, Tang Zheng, Peng Qian, Zhang Chunfeng, Cai Yunhao, Huang Hui
College of Materials Science and Opto-Electronic Technology Center of Materials Science and Optoelectronics Engineering CAS Center for Excellence in Topological Quantum Computation CAS Key Laboratory of Vacuum Physics, University of Chinese Academy of Sciences, 100049, Beijing, China.
National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
Nat Commun. 2024 Oct 15;15(1):8872. doi: 10.1038/s41467-024-53286-2.
The high non-radiative energy loss is a bottleneck issue that impedes the improvement of organic solar cells. The formation of triplet exciton is thought to be the main source of the large non-radiative energy loss. Decreasing the rate of back charge transfer is considered as an effective approach to alleviate the relaxation of the charge-transfer state and the triplet exciton generation. Herein, we develops an efficient ternary system based on D18:N3-BO:F-BTA3 by regulating the charge-transfer state disorder and the rate of back charge transfer of the blend. With the addition of F-BTA3, a well-defined morphology with a more condensed molecular packing is obtained. Moreover, a reduced charge-transfer state disorder is demonstrated in the ternary blend, which decreases the rate of back charge transfer as well as the triplet exciton formation, and therefore hinders the non-radiative recombination pathways. Consequently, D18:N3-BO:F-BTA3-based device produces a low non-radiative energy loss of 0.183 eV and a record-high efficiency of 20.25%. This work not only points towards the significant role of the charge-transfer state disorder on the suppression of triplet exciton formation and the non-radiative energy loss, but also provides a valuable insight for enhancing the performance of OSCs.
高非辐射能量损失是阻碍有机太阳能电池性能提升的一个瓶颈问题。三重态激子的形成被认为是大量非辐射能量损失的主要来源。降低电荷反向转移速率被视为缓解电荷转移态弛豫和三重态激子产生的一种有效方法。在此，我们通过调节共混物的电荷转移态无序度和电荷反向转移速率，开发了一种基于D18:N3-BO:F-BTA3的高效三元体系。随着F-BTA3的加入，获得了具有更紧密分子堆积的明确形态。此外，在三元共混物中证明了电荷转移态无序度降低，这降低了电荷反向转移速率以及三重态激子的形成，从而阻碍了非辐射复合途径。因此，基于D18:N3-BO:F-BTA3的器件产生了0.183 eV的低非辐射能量损失和创纪录的20.25%的高效率。这项工作不仅指出了电荷转移态无序度在抑制三重态激子形成和非辐射能量损失方面的重要作用，还为提高有机太阳能电池的性能提供了有价值的见解。
