Wang Yanbin, Zhuang Changlong, Fang Yawen, Kim Hyung Do, Yu Huang, Wang Biaobing, Ohkita Hideo
Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, School of Materials Science and Engineering, Jiangsu Collaborative Innovation Center of Photovolatic Science and Engineering, Changzhou University, Changzhou, Jiangsu, 213164, China.
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan.
Nanomaterials (Basel). 2020 Jan 29;10(2):241. doi: 10.3390/nano10020241.
A non-fullerene molecule named Y6 was incorporated into a binary blend of PBDB-T and IT-M to further enhance photon harvesting in the near-infrared (near-IR) region. Compared with PBDB-T/IT-M binary blend devices, PBDB-T/IT-M/Y6 ternary blend devices exhibited an improved short-circuit current density () from 15.34 to 19.09 mA cm. As a result, the power conversion efficiency (PCE) increased from 10.65% to 12.50%. With an increasing weight ratio of Y6, the external quantum efficiency (EQE) was enhanced at around 825 nm, which is ascribed to the absorption of Y6. At the same time, EQE was also enhanced at around 600-700 nm, which is ascribed to the absorption of IT-M, although the optical absorption intensity of IT-M decreased with increasing weight ratio of Y6. This is because of the efficient energy transfer from IT-M to Y6, which can collect the IT-M exciton lost in the PBDB-T/IT-M binary blend. Interestingly, the EQE spectra of PBDB-T/IT-M/Y6 ternary blend devices were not only increased but also red-shifted in the near-IR region with increasing weight ratio of Y6. This finding suggests that the absorption spectrum of Y6 is dependent on the weight ratio of Y6, which is probably due to different aggregation states depending on the weight ratio. This aggregate property of Y6 was also studied in terms of surface energy.
一种名为Y6的非富勒烯分子被掺入到PBDB-T和IT-M的二元共混物中，以进一步增强近红外（near-IR）区域的光子捕获。与PBDB-T/IT-M二元共混物器件相比，PBDB-T/IT-M/Y6三元共混物器件的短路电流密度（）从15.34提高到19.09 mA cm。结果，功率转换效率（PCE）从10.65%提高到12.50%。随着Y6重量比的增加，在825 nm左右外部量子效率（EQE）得到增强，这归因于Y6的吸收。同时，在600 - 700 nm左右EQE也得到增强，这归因于IT-M的吸收，尽管IT-M的光吸收强度随着Y6重量比的增加而降低。这是因为从IT-M到Y6的有效能量转移，其可以收集在PBDB-T/IT-M二元共混物中损失的IT-M激子。有趣的是，随着Y6重量比的增加，PBDB-T/IT-M/Y6三元共混物器件的EQE光谱不仅在近红外区域增加而且发生红移。这一发现表明Y6的吸收光谱取决于Y6的重量比，这可能是由于取决于重量比的不同聚集状态。还从表面能的角度研究了Y6的这种聚集性质。
