Schival Keith A, Gipson Robert R, Prather Keaton V, Tsui Emily Y
Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States.
Nano Lett. 2019 Nov 13;19(11):7770-7774. doi: 10.1021/acs.nanolett.9b02726. Epub 2019 Oct 14.
Organometallic surface functionalization of colloidal CdSe and CdS nanocrystals using iron tetracarbonyl moieties is demonstrated to enable study of in situ colloidal nanocrystal surface redox chemistry. Spectroscopic measurements of the surface-bound metal carbonyl C-O stretches were used to elucidate the coordination environments and local symmetry of surface sites. The C-O stretching frequencies of these fragments were correlated to the electric field induced by nanocrystal surface charges and shift in energy upon surface reduction or oxidation. These measurements revealed that CdSe nanocrystals can accumulate multiple surface electrons under -band gap photoexcitation, a process likely relevant to photoactivated nanocrystal processes such as photobrightening. These surface charges are stable for hours and decay extremely slowly under anaerobic conditions.
使用四羰基铁部分对胶体CdSe和CdS纳米晶体进行有机金属表面功能化，被证明能够研究原位胶体纳米晶体表面氧化还原化学。通过对表面结合的金属羰基C-O伸缩振动进行光谱测量，以阐明表面位点的配位环境和局部对称性。这些片段的C-O伸缩频率与纳米晶体表面电荷诱导的电场相关，并在表面还原或氧化时发生能量位移。这些测量结果表明，CdSe纳米晶体在带隙以下光激发下可以积累多个表面电子，这一过程可能与光活化纳米晶体过程（如光致发光）有关。这些表面电荷在数小时内保持稳定，在厌氧条件下衰减极其缓慢。
