Concentration detection of quantum dots in the visible and near-infrared range based on surface plasmon resonance sensor

We employ an optical sensor based on surface plasmon resonance (SPR) operating in the near-infrared and in the visible range to determine the concentration of CdSe/ZnS core-shell quantum dots (QDs) which are embedded in the SU8 organic films. Attenuated total reflection (ATR) measurements show that the amplitude of the shift of the resonance dip is closely related to the concentration variation of QDs in the organic films and the incident laser. The sensitivity is enhanced by 1.5-time and the detect limitation is expanded to 10−5μmol/L in the visible range as compared to that in the near-infrared. The sensitivity enhancement and the expansion of detect limitation of the visible SPR sensor may originate from the coupling of surface plasmons to luminescence from QDs.