CdSe/ZnS量子点和量子点-受体分子复合物的超快动力学研究  

Ultrafast Dynamics of CdSe/ZnS Quantum Dots and Quantum Dot-Acceptor Molecular Complexes

作　　者：白西林 彭越 张雪东 葛晶 BAI Xi-lin;PENG Yue;ZHANG Xue-dong;GE Jing(School of Physics and Information Engineering,Shanxi Normal University,Taiyuan 030031,China;Key Laboratory of Spectral Measurement and Analysis of Shanxi Province,Taiyuan 030031,China)

机构地区：[1]山西师范大学物理与信息工程学院,山西太原030031 [2]山西省光谱测量与分析重点实验室,山西太原030031

出　　处：《光谱学与光谱分析》2024年第1期56-61,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(21903050);山西省基础研究计划项目(20210302124124);山西省回国留学人员科研资助项目(2021-092);山西省留学人员科技活动择优资助项目(20220024);山西省高等学校科技创新计划项目(2021L256);山西省研究生教育教学改革课题项目(2021YJJG135)资助。

摘　　要：量子点(QD)作为一种新型的半导体纳米发光材料,由于其独特的光学性质,如发光颜色可调、尺寸可调、激发光谱宽和发射光谱窄等优点,自被发现以来一直备受关注。相比于单量子点而言,核/壳量子点更为优异的光学性能使其成为光伏器件应用中的理想材料,例如在量子点敏化太阳能电池中,Ⅰ型核/壳量子点太阳能电池器件表现出更高的稳定性和转换效率。然而,界面电荷转移和电荷复合过程如何影响器件性能一直是大家关注的焦点,相关方面认知的匮乏阻碍了量子点光伏器件的进一步发展。为了对电荷转移(CT)和复合过程有更加清晰的认识,通过利用飞秒时间分辨瞬态吸收(TA)光谱和量子化学计算相结合的方法,对Ⅰ型CdSe/ZnS核/壳量子点和三种量子点-电子受体分子(如1-氯蒽醌(1-CAQ)、蒽醌(AQ)和甲基紫(MV^(2+)))复合物的载流子动力学进行了全面而细致的研究。通过光谱分析表明,QD-MV^(2+)复合物发生了最快的电子转移(ET)和俄歇复合(AR)过程,并且ET速率与AR速率呈正相关关系。此外,根据Marcus ET理论和密度泛函理论计算,证明了电子受体的带隙和给受体之间的能级差作为驱动力是共同影响ET速率的关键因素。该研究为电子受体的选择提供了新的见解,对光伏器件的改进设计具有重要的指导意义。QDs are a new class of semiconductor light-emitting nanomaterials,which have attracted much attention due to their unique optical properties such as adjustable luminous colorand size,wide excitation spectrum,narrow emission spectrum,etc.It is the ideal material for photovoltaic device applications in which nuclear/shell QD has better optical performance than single QD.For instance,type I nuclear/shell QD solar cell devices show higher stability and conversion efficiency in quantum dot-sensitized solar cells.Nevertheless,how the interfacial process and recombination kinetics affect the performance of devices have been the focus of attention,and the lack of related cognition has hindered the further development of quantum dot photovoltaic devices.A comprehensive study on carrier dynamics of the topical CdSe/ZnS QDs and QD-acceptor(l-chloroanthraquinone(1-CAQ),anthraquinone(AQ),and methyl viologen(MV^(2+)))complexes are performed employing the femtosecond time-resolved transient absorption(TA)spectroscopy and quantum chemical calculations.As indicated by the spectroscopic analysis,the fastest ET and AR processes occurred in QD-MV^(2+)complexes,and the ET rate was positively correlated with the AR rate.In addition,the bandgap of electron acceptor molecules and the driving force were demonstrated as crucial factors affecting the rate of the ET process according to Marcus's ET theory combined with density function calculation.This study will provide new insights into the selection of electron acceptor molecules,which will be essential in improving the design of photovoltaic devices.

关 键 词：量子点 瞬态吸收光谱 密度泛函理论 电子转移 

分 类 号：O433.4[机械工程—光学工程]