Photochemical Electronic Doping of Colloidal CdSe Nanocrystals

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• 作者：Jeffrey D. Rinehart ; Alina M. Schimpf ; Amanda L. Weaver ; Alicia W. Cohn ; Daniel R. Gamelin
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：December 18, 2013
• 年：2013
• 卷：135
• 期：50
• 页码：18782-18785
• 全文大小：260K
• 年卷期：v.135,no.50(December 18, 2013)
• ISSN：1520-5126

文摘

A method for electronic doping of colloidal CdSe nanocrystals (NCs) is reported. Anaerobic photoexcitation of CdSe NCs in the presence of a borohydride hole quencher, Li[Etb>3b>BH], yields colloidal n-type CdSe NCs possessing extra conduction-band electrons compensated by cations deposited by the hydride hole quencher. The photodoped NCs possess excellent optical quality and display the key spectroscopic signatures associated with NC n-doping, including a bleach at the absorption edge, appearance of a new IR absorption band, and Auger quenching of the excitonic photoluminescence. Although stable under anaerobic conditions, these spectroscopic changes are all reversed completely upon exposure of the n-doped NCs to air. Chemical titration of the added electrons confirms previous correlations between absorption bleach and electron accumulation and provides a means of quantifying the extent of electron trapping in some NCs. The generality of this photodoping method is demonstrated by initial results on colloidal CdE (E = S, Te) NCs as well as on CdSe quantum dot films.