Enhancement of fluorescence of single quantum dots by encasing in semiconductor and metal nanoparticles

Abstract

Quantum dots (QDs) are widely investigated in the field of optoelectronics due to their various unique spectral and excellent fluorescence properties. However, QDs suffer from intermittent fluorescence, also known as blinking, that limits their use in optoelectronic devices. The blinking mechanism can be suppressed by numerous processes, and one such process includes the interaction of the QDs with semiconductor nanoparticles (NPs) such as indium tin oxide (ITO) and titanium dioxide (TiO2). By encapsulating the QDs in these NPs, the blinking rate is significantly reduced due to the electron transfer pathway between them. The interaction of QDs with metal NPs such as silver (Ag) and gold (Au) also greatly enhances the fluorescence behavior due to energy transfer and plasmonic effects. This work deals with the electron transfer model that analyzes the effect of radiative recombination, non-radiative recombination, and electron transfer between QDs and the NPs. An analysis of the on and off states for QDs under the influence of considered NPs has also been done. The on and off time for QDs have also been studied, which provide a comprehensive framework of the performance of the QDs interfaced with these NPs. A comparison between the QDs interacting with glass and other semiconductor and metal NPs is also drawn to compare the efficacy of QDs under the influence of different NPs. This analysis postulates the physical mechanism for blinking and ways to curb these mechanisms using the semiconductor and metal NPs. The theoretical study demonstrates the quantitative insights and prerequisites for designing QD-based optoelectronic devices.