Iqbal Muniba, Hussain Ajaz, Naz Asma, Hussain Riaz, Yar Muhammad, Ayub Khurshid, Shah Gilani M Rehan H, Imran Muhammad, Assiri Mohammed A
Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800, Pakistan.
Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800, Pakistan.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Apr 15;291:122322. doi: 10.1016/j.saa.2023.122322. Epub 2023 Jan 5.
Y-series-based non-fullerene acceptors (NFAs) have achieved significant deliberation by chemists and physicists because the promising optical and photochemical properties associated with high-performance OSCs can be further tuned through end-capped modification. In this work, such modifications of Y-series benzothiadiazole-based NFAs were accomplished theoretically to propose new acceptors for photovoltaic cells (PVCs). The recently synthesized Y-series non-fullerene acceptor m-BTP-PhC6 was taken as a reference acceptor. We designed five new acceptors (BTP1-BTP5) through the structural modification at both ends of acceptor groups and evaluated their performance by applying DFT and TD-DFT. The newly engineered molecules exhibited a narrower bandgap (E) than the reference (R) resulting in better intramolecular charge transfer (ICT). Further, the designed acceptors expressed the maximum absorption in the region of 600-800 nm revealing a redshift in their absorption spectrum. Low excitation energy and low exciton binding energy were noted for designed acceptors confirming them as better candidates for high PCE of solar cells. Low reorganizational energy for the mobility of holes and electrons was also observed for the designed molecules, indicating improved charge transfer properties. The newly tailored acceptor BTP4 was found to be the promising candidate among all acceptors because of lower bandgap, lower exciton binding energy, reorganizational energy, and redshift of the absorption spectrum. The complex analysis of BTP4 with donor polymer PTB7-Th and PM6 was executed at the same DFT level. Furthermore, FMOs studies showed relatively rich electron density in the acceptor groups of LUMO as compared to the reference molecule. The overall theoretical results of this study showed that the designed acceptors played a productive and effective role in uplifting the efficiency of fullerene-free energy devices.
基于Y系列的非富勒烯受体（NFAs）已引起化学家和物理学家的广泛关注，因为与高性能有机太阳能电池（OSCs）相关的有前景的光学和光化学性质可通过封端修饰进一步调节。在这项工作中，从理论上完成了对基于Y系列苯并噻二唑的NFAs的此类修饰，以提出用于光伏电池（PVCs）的新型受体。最近合成的Y系列非富勒烯受体m-BTP-PhC6被用作参考受体。我们通过对受体基团两端进行结构修饰设计了五个新受体（BTP1-BTP5），并应用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）评估了它们的性能。新设计的分子表现出比参考分子更窄的带隙（E），从而导致更好的分子内电荷转移（ICT）。此外，设计的受体在600 - 800 nm区域表现出最大吸收，表明其吸收光谱发生红移。设计的受体具有低激发能和低激子束缚能，这证实它们是用于高功率转换效率（PCE）太阳能电池的更好候选者。还观察到设计分子的空穴和电子迁移的重组能较低，表明电荷转移性能得到改善。新定制的受体BTP4因其较低的带隙、较低的激子束缚能、重组能以及吸收光谱的红移，被发现是所有受体中有前景的候选者。在相同的DFT水平上对BTP4与供体聚合物PTB7-Th和PM6进行了复合物分析。此外，前线分子轨道（FMOs）研究表明，与参考分子相比，最低未占分子轨道（LUMO）的受体基团中电子密度相对丰富。这项研究的总体理论结果表明，设计的受体在提高无富勒烯能量器件的效率方面发挥了有效作用。
