Efficient electrogenerated chemiluminescence from cyclometalated iridium(III) complexes.
ABSTRACT Very efficient electrogenerated chemiluminescence (ECL) phenomena were realized by deliberately tuning electron-transfer reactions from electrochemically generated electron donor to metal complex radical cations. By controlling the relative positions of HOMO and LUMO levels (oxidation potential and reduction potential) of Ir(III) complexes, we could obtain 77 times higher ECL from iridium(III) complexes in the presence of TPA than that of the Ru(bpy)32+/TPA system. This high ECL efficiency of new Ir(III) complexes can be used in many interesting applications such as sensors and luminescent devices.
[show abstract] [hide abstract]
ABSTRACT: Electrogenerated chemiluminescence (ECL) of CdSe quantum dots (QDs) dispersed in aqueous solution was studied with bare electrode. The ECL emission was observed at -1.4 V vs. Ag/AgCl and the ECL spectrum peak is similar to that of the defect photoluminescence (PL) spectrum, indicating the surface defects played a critical role in the emission process. The experiment results suggested that dissolved oxygen had a great effect on the ECL intensity. Other influence factors including the electrochemical parameters and QDs concentration were investigated in detail. As an application of the CdSe QDs ECL, the pyrogallol (1, 2, 3-trihydroxybenzene) was detected in aqueous solution. Under the optimal conditions, a linear relationship between ECL intensity and pyrogallol concentration was obtained in the range from 4.0 x 10(-7) to 2.0 x 10(-5) M with a correlation coefficient of 0.9904 and the limit of detection was 6.6 x 10(-8) M (S/N = 3). A possible mechanism about ECL of QDs was also discussed.Frontiers in Bioscience 02/2007; 12:2352-7. · 3.52 Impact Factor