不同取代基对联苯二酰亚胺基空穴传输材料光电性能的影响

Influence of Different Substituents on Photoelectric Properties of Biphenyl Imide Group Hole Transport Materials

本工作设计了四种以联苯二酰亚胺为核心的新型空穴传输材料(HTMs),并且分别研究了含H、OH、OMe和NH_(2)取代基对其性能的影响。基于密度泛函理论(DFT),讨论了所设计的分子的几何结构、前线分子轨道(FMOs)、HOMO-LUMO能级能隙、态密度(DOS)、绝对硬度、静电势(ESP)以及空穴传输速率。基于含时密度泛函理论(TD-DFT),讨论了空穴传输材料分子的吸收光谱、电荷密度差图(CDD)、热图、D指数、H指数、S_(r)指数、激子结合能(E_(coul))以及片段间的电子转移量。模拟计算结果表明:设计的HTMs的能级都与钙钛矿层(MAPbI_(3))的能级匹配,并且都具有较高的稳定性和空穴传输速率。根据溶解自由能的研究结表明:设计的分子均可溶于二氯甲烷溶剂中。所有的分子在200~400 nm之间有较为明显的吸收峰,不会与钙钛矿层在可见光区域发生光吸收竞争,并且光激发过程电子是从给体转移到受体;所设计的HTMs具有良好的电学性质、光学性质、空穴传输速率和稳定性,该研究为高效性能的空穴传输材料的设计提供了新的思路。

In this study,we designed four new hole transport materials(HTMs)in perovskite solar cells(PSCs)and studied the effects of the different substituent groups on their performance.Based on density functional theory(DFT),we investigated the geometry,frontier molecular orbi-tals(FMOs),density of states(DOS),solvation free energy(ΔG sol),absolute hardness,electrostatic potential(ESP),and hole transport rates of all designed molecules.Time-dependent density functional theory(TD-DFT)was used to analyze the absorption spectra,charge density difference diagrams(CDD),heat maps,D index,H index,S r index,exciton binding energy(E_(coul)),and the electron transfer of the designed HTMs.The simulation findings demonstrate that the studied HTMs molecular energy levels match the energy level of perovskite(MAPbI 3).Additionally,all designed molecules have good stability and high hole transport rates.Based on the solubility free energies,the designed HTMs were all found to be soluble in the dichloromethane solvent.The UV-visible absorption spectra show that the designed HTMs can broaden the optical absorption range of PSCs in the visible light region.In addition,the photoexcitation process is the transfer of electrons from the donor to the receptor.The designed molecules exhibit great electronic character,optical character,hole transport rates,and stability,which provide ideas for the future design of high-efficiency HTMs.