Ligand-dependent aggregation-enhanced photoacoustic of atomically precise metal nanocluster  

作　　者：Changlin Zhou Meng Wang Qiaofeng Yao Yu Zhou Chuantao Hou Jianfei Xia Zonghua Wang Jishi Chen Jianping Xie 

机构地区：[1]College of Chemistry and Chemical Engineering,Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials,Instrumental Analysis Center of Qingdao University,Qingdao University,Qingdao,P.R.China [2]Tianjin Key Laboratory of Molecular Optoelectronic Sciences,Department of Chemistry,School of Science,Tianjin University,Tianjin,P.R.China [3]Qingdao Boting Hydrogen Age Ocean Technol R&D Ctr.,Qingdao Boting Technol Co.Ltd.,Shandong Hydrogen Times Marine Technology Co.Ltd.,Qingdao,P.R.China [4]Department of Chemical and Biomolecular Engineering,National University of Singapore,Singapore [5]Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Binhai New City,Fuzhou,P.R.China

出　　处：《Aggregate》2024年第1期196-203,共8页聚集体（英文）

基　　金：Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2020MB063;Taishan Scholar Program of Shandong Province,Grant/Award Number:ts201511027。

摘　　要：Atomically precise metal nanoclusters(MNCs),as a potential type of photoacoustic(PA)contrast agent,are limited in application due to their low PA conversion efficiency(PACE).Here,with hydrophilic Au25SR18(SR=thiolate)as model NCs,we present a result that weakly polar solvent induces aggregation,which effectively enhances PA intensity and PACE.The PA intensity and PACE are highly dependent on the degree of aggregation,while the aggregation-enhanced PA intensity(AEPA)positively correlates to the protected ligands.Such an AEPA phenomenon indicates that aggregation actually accelerates the intramolecular motion of Au NCs,and enlarges the proportion of excited state energy dissipated through vibrational relaxation.This result conflicts with the restriction of intramolecular motion mechanism of aggregation-induced emission.Further experiments show that the increased energy of AEPA originates from the aggregation inhibiting the intermolecular energy transfer from excited Au NCs to their surrounding medium molecules,including solvent molecule and dissolved oxygen,rather than restricting radiative relaxations.This study develops a new strategy for enhancing the PA intensity of Au NCs,and contributes to a deeper understanding of the origin of the PA signal and the excited state energy dissipation processes for MNCs.

关 键 词：aggregation-enhanced photoacoustic gold nanocluster intermolecular excited state energy transfer intramolecular motion ligand effect 

分 类 号：O62[理学—有机化学]