End‐capped modification is a convenient strategy to enhance the photovoltaic and electronic properties of fullerene‐free acceptor materials. In this report, five novel star‐shaped three‐dimensional acceptor molecules FH1–FH5 are designed by end‐capped modifications of recently synthesized star‐shaped Tr (Hex)₆‐3BR molecule. The enhancement in the photovoltaic, electronic, and photophysical properties of designed molecules is examined with the aid of density functional theory (DFT) and time‐dependent DFT (TDDFT). The MPW1PW91 functional in conjunction with 6‐31G(d,p) basis set of DFT/TDDFT is employed in order to compute various key parameters including frontier molecular orbitals analysis, absorption maxima, and binding energy along with transition density matrix, open‐circuit voltage, excitation energy, charge mobilities (electron and hole reorganizational energies), density of states, charge transfer with respect to HOMO_PTB7‐Th–LUMO_acceptor, and dipole moment. Red shifting in absorption spectra of acceptor materials is the most important reason for increasing efficiency of organic solar cells. A red shift in absorption spectra of all designed molecules is noted with low excitation energy. Designed molecules FH1–FH5 exhibit narrow energy gap with high electron mobility as compared with Tr (Hex)₆‐3BR molecule. Among all designed molecules, FH4 is proved to be the best candidate for fullerene free organic solar cells because of narrow band gap, high charge mobility, high dipole moment, low excitation, and binding energy along with a red shift in absorption spectrum. Moreover, all designed molecules offer high current charge density as compared with Tr (Hex)₆‐3BR. These results indicate that all star‐shaped conceptual molecules (FH1–FH5) are ideal aspirants for construction of future organic solar cells.

中文翻译：

---

含富勒烯核的高性能3D星形电子受体的分子设计，用于非富勒烯有机太阳能电池

封端修饰是增强无富勒烯受体材料的光伏和电子性能的便捷策略。在本报告中，通过对最近合成的星形Tr（Hex）₆进行封端修饰，设计了五个新颖的三维三维受体分子FH1-FH5‐3BR分子。借助密度泛函理论（DFT）和时变DFT（TDDFT）检验了设计分子在光伏，电子和光物理性质方面的增强。使用MPW1PW91与DFT / TDDFT的6-31G（d，p）基本功能结合使用，以计算各种关键参数，包括前沿分子轨道分析，吸收最大值和结合能以及跃迁密度矩阵，开路电压，激发能，电荷迁移率（电子和空穴重组能），状态密度，相对于HOMO _PTB7-Th –LUMO_受体的电荷转移和偶极矩。受体材料吸收光谱的红移是提高有机太阳能电池效率的最重要原因。所有设计分子的吸收光谱均出现红移，激发能较低。与Tr（Hex）₆ -3BR分子相比，设计的分子FH1-FH5具有窄的能隙和高的电子迁移率。在所有设计的分子中，由于窄带隙，高电荷迁移率，高偶极矩，低激发和结合能以及吸收光谱的红移，FH4被证明是不含富勒烯的有机太阳能电池的最佳候选者。此外，与Tr（Hex）₆相比，所有设计的分子均提供高电流电荷密度‐3BR。这些结果表明，所有星形概念分子（FH1–FH5）都是构建未来有机太阳能电池的理想愿望。