Enhanced anodic electrochemiluminescence due to efficient exchange recombination and its sensing application

• Published in: Surfaces and interfaces Vol. 30; p. 101919
• Main Authors: Linghu, Shaomei, Wu, Ziyong, Zhu, Yuan, Song, Huaju, Wang, Ying, Zhou, Zhiping, Shan, Yun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2022
• Subjects: Anodic electrochemiluminescence; CdS nanocrystals; Detection; Dopamine; Mn2+ doping; Anodic electrochemiluminescence; Dopamine; CdS nanocrystals; Detection; Mn2+ doping
• ISSN: 2468-0230; 2468-0230
• DOI: 10.1016/j.surfin.2022.101919

To obtain semiconductor nanocrystals (NCs) with strong anodic electrochemiluminescence (ECL) remains a challenge due to their insufficiency to resist following corrosion upon holes injection to the NCs. Herein, we report strong and stable anodic ECL generated from 0.8 at% Mn2+ doped CdS NC films on indium tin oxide (ITO) electrode in the presence of coreactant triethanolamine (TEOA) under potential scan to +1.5 V vs. saturated calomel electrode (SCE), which is much more negative than the valence band potential of host NCs. The Mn2+ doping leads to an 8-fold enhancement in anodic ECL intensity in comparison with undoped CdS NC films due to efficient Mn excitation via nonradiative recombination energy transfer, i.e., exchange recombination. The efficiency is dependent on Mn2+ doping amount as well as applied potential for holes injection with the maximum obtained when the charge transfer to Mn dopants is possible and the energy gap between conduction band and applied potential matches with Mn excitation. This anodic ECL was used to detect dopamine, a model analyte, showing a wide linear range from 5 nM to 1 μM with a detection limit of 1 nM at S/N=3. This work provides a new insight into ECL generation in doped semiconductor NCs. The Mn2+ doped CdS NCs passivated by carboxylic groups display great potential in future development of biosensors. The 0.8 at% Mn2+ doped CdS NC films generate 8 folds stronger ECL than undoped ones under electrode potential scan to +1.5 V, a value much more negative than the valence band potential, which is due to efficient Mn excitation via nonradiative recombination energy transfer. [Display omitted]