Work

Influence of excitation pulse duration on the efficiency of upconversion nanoparticle-based FRET

Year: 2025

Type: article

Abstract: UCNPs functionalized with Cy3 dyes. Time-resolved upconversion luminescence (UCL) measurements reveal that apparent FRET efficiencies decrease with increasing excitation pulse duration and power. These variations stem from excitation-induced changes in the UCL lifetime, arising from the complex dynamics that accompany the upconversion emission process. A dynamic rate equation model reproduces the experimental trends, confirming that excitation parameters alter emissive state kinetics and thus bias lifetime-based FRET measurements. Our findings identify excitation conditions as a hidden variable in UCNP-FRET experiments and underscore the need for standardized measurement protocols.

Source: Nanoscale

DOI: 10.1039/d5nr01779c