基于二酮基吡咯并吡咯的π-共轭分子的有机太阳能电池给体材料的设计与理论研究  

Design and theoretical characterisation of diketopyrrolopyrrole-based π-conjugated molecules as donor materials for organic solar cells

作　　者：姜哓玲 孙福玉 JIANG Xiao-ling;SUN Fu-yu(School of Physics and Intelligent Manufacturing Engineering,Chifeng University,Chifeng 024000,China)

机构地区：[1]赤峰学院物理与智能制造工程学院,内蒙古赤峰024000

出　　处：《分子科学学报》2023年第1期68-77,共10页Journal of Molecular Science

基　　金：内蒙古自治区高等学校科学研究项目(NJZY20196)。

摘　　要：本文设计了系列基于二酮基吡咯并吡咯(DPP)的有机小分子太阳能电池(OSCs)给体材料.设计的分子结构中,2个DPP分子片段作为2个端基通过不同的芳香杂环π-桥相连接.利用密度泛函理论和含时密度泛函理论方法研究了所设计化合物的电子和光学性质.研究结果表明,在分子中引入不同的π-桥可以有效调节设计分子的前线分子轨道能量、能隙和吸收光谱,但是对几何结构影响很小.所设计化合物1-8均在近红外光谱区具有强吸收和窄能隙,这有利于提高有机太阳能电池的短路电流和光吸收效率.前线分子轨道分析发现,化合物1-8具有较低的最高占据轨道能级,可提高有机太阳能电池的开路电压.化合物1-3,5和7的前线分子轨道能级与典型富勒烯受体材料相匹配,可选用PCBM,bisPCBM和PC71BM作为受体材料;而化合物4,6和8则应考虑选用其他的太阳能电池受体材料.结果表明,所设计的分子可作为性能优良的OSCs给体材料,为开发和利用太阳能电池给体材料提供理论依据.Organic solar cells(OSCs) have become promising candidates to address the traditional energy depletion and environmental pollution. OSCs have attracted great attention all over the world owing to their outstanding merits, including low production costs, lightweight, highly flexible and so on. In particular, the small molecule based OSCs(SMOSCs) have received tremendous interest due to their prominent advantages over polymer solar cells(PSCs), such as excel with well-defined molecular structures, high purity, good absorption coefficient, excellent batch-to-batch reproducibility. With continuous efforts, significant advances have been demonstrated for OSCs. Recently, the power conversion efficiency(PCE) of PSCs and SMOSCs have exceeded 10%. However, the overall performance of SMOSCs still lags behind that of PSCs. Accordingly, it remains a great challenge to achieve high performance SMOSCs. Generally, small molecules donor materials should exhibit lower band gap in order to harvest more sunlight and enhance the short-circuit current density(Jsc). Another key characteristic of ideal donor materials should have suitable frontier molecular orbitals(FMOs) energy levels. The deep highest occupied molecular orbital(HOMO) of donor materials is favourable for enhancement the open circuit voltage(Voc). In addition, the downhill energetic driving force(ΔEL-L) has a dominant impact on the efficient exciton splitting and charge dissociation. The ΔEL-Lvalue should at least amount to 0.2 eV. Furthermore, theoretical approaches are capable of providing useful insights to the understanding of the nature of the molecular electronic structures and optical property of materials for OSCs. Among the various small molecular donors for SMOSCs, diketopyrrolopyrrole(DPP) based materials are promising building blocks in terms of their unique π-conjugated system, broadened absorption region, and good weather and heat stability. A series of novel DPP-based small molecules with DPP fragments as end groups and different conjugate π-bridges

关 键 词：二酮基吡咯并吡咯 有机太阳能电池 前线分子轨道 吸收光谱 

分 类 号：O641[理学—物理化学]