Excitonic chemiluminescence in Si and CdSe nanocrystals induced by their interaction with ozone

The results of a systematic study of spectral and kinetic patterns of ozone-adsorption-induced luminescence (AL) in nanostructured Si and, for the first time, in colloidal CdSe/ZnS quantum dots (QDs) are reported and compared with photoluminescence (PL) of the same structures. The common excitonic nature of light emission under ozone chemisorption and photoexcitation is confirmed by excellent coincidence of AL and PL emission bands. This coincidence is maintained during correlated quenching of AL and PL emission caused by nonradiative defects generated under ozone adsorption. A possible mechanism for energy conversion is proposed in the framework of an exothermic oxidation reaction of core materials caused by ozone. The significant role of the quantum confinement effect differentiates the observed phenomenon from well-known chemiluminescence in molecular systems. This research establishes a physicochemical basis for the development of a gas sensor with high selectivity to ozone. Also, our findings may be useful for testing core-shell colloidal QDs with ozone.