A robust and unique approach for tuning the energy level of Ag_(2)Se quantum dots via“on-surface”manipulation of nitrogencontaining groups of surface-coordinated ligands  

作　　者：Meng-Yao Luo Bo Tang An-An Liu Jing-Ya Zhao Zhi-Ling Zhang Dai-Wen Pang 

机构地区：[1]The Institute for Advanced Studies and College of Chemistry and Molecular Sciences,Wuhan University,Wuhan 430072,China [2]State Key Laboratory of Medicinal Chemical Biology,Tianjin Key Laboratory of Biosensing and Molecular Recognition,Frontiers Science Center for New Organic Matter,Research Center for Analytical Sciences,College of Chemistry,Frontiers Science Center for Cell Responses,Nankai University,Tianjin 300071,China [3]Haihe Laboratory of Sustainable Chemical Transformations,Tianjin 300192,China

出　　处：《Nano Research》2023年第11期12608-12617,共10页纳米研究（英文版）

基　　金：supported by the National Key Research&Development Program of China(No.2019YFA0210100);the National Natural Science Foundation of China(Nos.91859123 and 21827808);the Haihe Laboratory of Sustainable Chemical Transformations for financial support。

摘　　要：Effects of surface chemistry on energy levels or optical properties of semiconductor nanocrystals have attracted considerable attention and show great promise in broad applications.Yet,it remains challenging to controllably tune the photoluminescence(PL)of quantum dots(QDs)by manipulating surface ligands.Herein,we investigated effects of the ligand,glutathione(GSH),on PL properties of near-infrared(NIR)Ag_(2)Se QDs by“on-surface”manipulation,that is,precisely manipulating the chelating group without dissociating the ligand from the surface.The anchoring of the amino group was found to be controlled by solution pH,whereas the binding of the thiol group to the Ag+was pH independent,maintaining the“on-surface”state of GSH.By tuning the pH-controlled binding of amino groups,the energy level or the bandgap of Ag2Se QDs could be increased by up to 140 meV.The increased bandgap resulted in the blueshift of PL spectrum,which could be reversibly tuned by up to 75 nm.The pH-mediated tunable PL properties of QDs could also be extended to other nitrogen-containing pH-sensitive groups which could coordinate to the Ag+,not limited to the amino group.Our work would facilitate the study of nanocrystal surface chemistry and our model that the binding of amino groups affected energy levels of Ag2Se QDs might facilitate new insights into the electronic structure and energy level of other QD-ligand complexes.

关 键 词：quantum dot(QD) surface chemistry LIGAND energy level pH 

分 类 号：O62[理学—有机化学]