Simulation modelling of a micro-system for time-resolved fluorescence measurements

This paper presents the simulation modelling of a typical experimental setup for time-resolved fluorescence measurement. The developed model takes into account the setup geometry, characteristics of light source, detector and fluorescent sample as well as the adopted measurement technique. A qualitative verification of the model has been reported before. In this paper, we present a quantitative analysis and verification of the system versatility. For this we conducted time-resolved fluorescence measurements using a two-chip based micro-system, including a blue micro-LED array as a light source and a CMOS SPAD array as a detector. The sample of interest (CdSe/ZnS quantum dots in toluene) in a micro-cavity slide and an excitation filter were placed in the gap between the excitation and detection planes. A time-correlated single photon counting module was used to build fluorescence decay curves. A range of experiments with different excitation light pulse widths and using several setups have been performed. The simulated data are in good agreement with measured results and the model proves to be flexible enough to simulate different light sources and detector quenching/recharging circuits. This model can be used to predict qualitative and quantitative results for specific experimental setups, supporting the explanations of observed effects and allowing the realisation of virtual experiments.