Device performance is set by what happens to a photon in the first few picoseconds after absorption — whether the excitation forms a free carrier or a bound exciton, how fast it thermalizes, where it becomes trapped and how it recombines. We measure these processes directly in halide perovskite thin films and nanocrystals and in organic semiconducting films.

Our optical laboratory combines time-correlated single-photon counting, temperature-dependent photoluminescence and single-emitter confocal microscopy. Measuring one nanocrystal at a time reveals blinking statistics, spectral diffusion, Auger rates and exciton fine structure that ensemble averaging hides. The results feed directly back into the materials and device work elsewhere in the group.

Current research directions:

• Time-resolved photoluminescence of perovskite and organic films.

• Single-emitter photoluminescence and photon statistics.

• Exciton binding energy, trap states and recombination pathways.

• Structure–property relationships guiding device design.