Li Zhipeng, Wu Shuo, Zhang Bin, Fu Li, Zou Guizheng
School of Chemistry , Dalian University of Technology , Dalian 116023 , China.
School of Chemistry and Chemical Engineering , Shandong University , Jinan 250100 , China.
J Phys Chem Lett. 2019 Sep 19;10(18):5408-5413. doi: 10.1021/acs.jpclett.9b02400. Epub 2019 Aug 30.
Screening novel electrochemiluminescence (ECL) systems with less inherent interference is strongly anticipated for ECL evolution. Herein, near-infrared ECL (∼730 nm) with an ultralow triggering potential of 0.45 V (vs Ag/AgCl) is achieved under physiological conditions with 4-mercaptobenzoic acid (MBA) and citrate capped CuInS@ZnS (CIS@ZnS) nanocrystals (NCs), which is promising for less autofluorescence and electrochemical interference. Cu species within the CIS@ZnS NCs can be electrochemically oxidized at 0.45 V to form internal Cu defects, while the capping agent MBA can bridge a direct charge transfer between the oxidized NCs and the traditional coreactant tripropylamine (TPrA) for weak ECL at 0.45 V. When hydrazine hydrate is adopted as coreactant, CIS@ZnS NCs/hydrazine hydrate exhibits 8k-fold enhanced oxidative-reduction ECL via the internal Cu/Cu couple cycling at 0.45 V in comparison to CIS@ZnS NCs/TPrA. This work opens a way to enhance the radiative charge transfer of NCs.
人们强烈期望筛选出具有较少固有干扰的新型电化学发光（ECL）系统以推动ECL的发展。在此，利用4-巯基苯甲酸（MBA）和柠檬酸盐包覆的CuInS@ZnS（CIS@ZnS）纳米晶体（NCs）在生理条件下实现了触发电位低至0.45 V（相对于Ag/AgCl）的近红外ECL（~730 nm），这对于减少自发荧光和电化学干扰很有前景。CIS@ZnS NCs中的铜物种可在0.45 V下被电化学氧化形成内部铜缺陷，而封端剂MBA可在氧化的NCs与传统共反应剂三丙胺（TPrA）之间架起直接电荷转移的桥梁，从而在0.45 V下产生微弱的ECL。当采用水合肼作为共反应剂时，与CIS@ZnS NCs/TPrA相比，CIS@ZnS NCs/水合肼通过在0.45 V下的内部Cu/Cu偶循环表现出增强8000倍的氧化还原ECL。这项工作为增强NCs的辐射电荷转移开辟了一条途径。
