Diffusion Controlled Fluorescence Quenching of CsPbBr3 Perovskites

Semiconductor nanoparticles and their assemblies are considered as building blocks of next generation nanoscale electronic devices. In particular, for light harvesting applications, the excitation energy need to be transferred efficiently to the sink. Therefore, basic understanding of the fluorescence energy transfer occurring in nanoparticles is quite important. Colloidal semiconductor quantum dots (QDs) without heavy metal, such as CuInS2 (CIS), InP, different types of perovskites etc. are versatile materials for future applications due to their low toxicity and excellent optical properties. Through this proposal, we aim to investigate the diffusion-controlled fluorescence quenching of above-mentioned QDs mixtures and QD-dye assemblies in solution and film. The open questions are (a) is the quenching process static or dynamic in nature? (b) In the case of collisional quenching, how does the size of the quencher influence the quenching efficiency? (c) How does the charge carrier trapping on the surface of QDs and subsequent stabilization influence the quenching dynamics? To answer these questions, steady state and time-resolved optical measurements will be carried out in solution as well as in thin films. For the thin film samples, fluorescence microscope equipped with a spectrometer will be used. This approach will allow us to study the quenching of QDs in films locally (tens of micrometer size). Further, theoretical modelling of diffusion and binding of quencher on the surface of donor QD will provide information on molecular level.

Semiconductor nanoparticles and their assemblies are considered as building blocks of next generation nanoscale electronic devices. In particular, for light harvesting applications, the excitation energy need to be transferred efficiently to the sink. Therefore, basic understanding of the fluorescence energy transfer occurring in nanoparticles is quite important. Colloidal semiconductor quantum dots (QDs) without heavy metal, such as CuInS2 (CIS), InP, different types of perovskites etc. are versatile materials for future applications due to their low toxicity and excellent optical properties. Through this proposal, we aim to investigate the diffusion-controlled fluorescence quenching of above-mentioned QDs mixtures and QD-dye assemblies in solution and film. The open questions are (a) is the quenching process static or dynamic in nature? (b) In the case of collisional quenching, how does the size of the quencher influence the quenching efficiency? (c) How does the charge carrier trapping on the surface of QDs and subsequent stabilization influence the quenching dynamics? To answer these questions, steady state and time-resolved optical measurements will be carried out in solution as well as in thin films. For the thin film samples, fluorescence microscope equipped with a spectrometer will be used. This approach will allow us to study the quenching of QDs in films locally (tens of micrometer size). Further, theoretical modelling of diffusion and binding of quencher on the surface of donor QD will provide information on molecular level.