The performance of organic cells based on bulk heterojunctions (BHJs) has improved recently, but further improvements are necessary. In this work, we have carried out a thorough examination using density functional theory (DFT) and time-dependent (TD)-DFT to investigate the structural and optoelectronic properties of pentacene-based organic molecules (PbOMs) as potential donor material for organic photovoltaic BHJ devices. Our results show that oxadiazole prefers to attach via its nitrogen atoms to the carbon atoms of the pentacene monomer with an adsorption energy about − 32.86 kcal/mol, which means that oxadiazole is efficiently adsorbed on the edge of the pentacene. The HOMO energy level of the PbOM with the lowest bandgap is − 4.00 eV wide, i.e., about 0.86 eV lower and more positive than pentacene, thus providing an ideal open-circuit voltage for photovoltaic devices. The bandgap of the PbOM compounds are about 1.61 and 1.80 eV affording an efficient charge transfer from donor to acceptor. Furthermore, the donor PbOMs are also more stable than the pentacene. We have examined, additionally, the reactivity and absorption properties of individual molecules and PbOM systems. Our results suggest that the PbOM, as a donor material, may significantly improve the efficiency of BHJ solar cells.

中文翻译：

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DFT和TD-DFT研究新的并五苯有机分子作为体异质结太阳能电池的供体材料

最近，基于体异质结（BHJ）的有机电池的性能有所提高，但是有必要进行进一步的改进。在这项工作中，我们使用密度泛函理论（DFT）和时变（TD）-DFT进行了深入研究，以研究并五苯基有机分子（PbOMs）作为有机光伏潜在供体材料的结构和光电性能。 BHJ设备。我们的结果表明，恶二唑更喜欢通过其氮原子连接到并五苯单体的碳原子上，其吸附能约为-32.86 kcal / mol，这意味着恶二唑被有效地吸附在并五苯的边缘。带隙最低的PbOM的HOMO能级为-4.00 eV宽，即比并五苯低约0.86 eV，且比并五苯更正，从而为光伏设备提供理想的开路电压。PbOM化合物的带隙约为1.61和1.80 eV，可实现从供体到受体的有效电荷转移。此外，供体PbOM也比并五苯更稳定。我们还检查了单个分子和PbOM系统的反应性和吸收特性。我们的结果表明，PbOM作为供体材料可以显着提高BHJ太阳能电池的效率。