Tunable electrogenerated chemiluminescence from CdSe nanocrystals

Abstract

Electrochemical behavior and related optoelectronic properties of CdSe nanocrystals (NCs) in aprotic solutions have been investigated. NCs of 2.50 ± 0.50 nm diameter were synthesized using a modified procedure in which the temperatures at the time of Se precursor injection and NC growth were controlled. The electrochemical band gap was found to agree with those determined by UV–vis absorption spectroscopy and by the tunneling current-voltage spectrum in the literature. Electrogenerated chemiluminescence of the NCs with peak maxima at 1.90 eV (red, 653 nm) and 2.55 eV (blue, 486 nm) can be generated and altered by scanning the voltage between –1.60 and –1.80 V and between –2.00 and –2.20 V, respectively. The results demonstrate the potential capability of the NCs for light emission tuned by the applied potential.Key words: CdSe nanocrystals, electrochemistry, electrogenerated chemiluminescence, UV–vis spectroscopy, photoluminescence.