【摘要】 报道了通过硫醇配体实现Cu纳米团簇发光特性的调控.光致发光谱(PL)显示,在初始合成的2-巯基-5-正丙烷基嘧啶(MPP)包覆的Cu纳米团簇溶液中逐渐增加十二硫醇(C12SH)的浓度,Cu纳米团簇主发光峰的波长从623 nm逐渐蓝移到584 nm.质谱结果显示,在配体交换过程前后,Cu纳米团簇中Cu原子数目保持不变,但随加入的C12SH的浓度增加,C12SH逐渐取代原有的MPP配体.通过X射线吸收精细结构(XAFS)技术进一步研究了溶液中发生配体交换过程的Cu纳米团簇的原子结构变化.结果表明,随着C12SH浓度的增加,金属特征的Cu—Cu配位消失,Cu—S键长从0.228 nm缩短到0.224 nm,同时Cu—S之间的电荷转移增多,C12SH的刻蚀使得Cu纳米团簇的原子构型由初始的四面体排布展开为"—S—Cu—S—"一维链状结构,导致团簇整体发生金属性到共价性的转变,从而引起光致发光和吸收波长的显著蓝移.更多还原

【Abstract】 A study on tuning the fluorescence property of Cu nanoclusters by thiol ligands was presented. The photoluminescence( PL) measurements show that the luminescent wave-length of Cu nanoclusters capped by 2-mercapto-5-n-propylpyrimidine( MPP) is gradually blue-shifted from 623 nm to 584 nm, with increasing concentrations of dodecanethiol( C12SH) added into the solution. The added thiol ligands,as suggested by mass spectra,do not change the number of Cu atoms in the clusters,but replace some of the original MPP ligands. X-ray absorption fine structure( XAFS) spectra reveal that with the increment of C12 SH ligands,the Cu—Cu bonds disappear,the Cu—S bond length is contracted from the original 0. 228 nm to 0. 224 nm,and the charge transfer from Cu to S is enhanced. Moreover,the etching effect of C12 SH ligands leads to the change of atomic configuration of the Cu cores from the tetrahedron-alike structure to the chain-like structure of —S—Cu—S—. As a result,the electronic features of the Cu clusters show a metallic-to-covalent transition,resulting in the blue-shift of theluminescence and optical absorption wavelengths.更多还原