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Updated: May 16, 2025

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Exploring many-body phenomena: biexciton generation and auger recombination in Ag2S-based nanocrystals
Victor Vega-Mayoral1,2, Saül Garcia-Orrit1, Peijiang Wang3
1IMDEA Nanoscience, Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain. victor.vega@imdea.org.
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The optoelectronic properties of Ag2S nanocrystals with different surface passivation treatments have been investigated using femtosecond transient absorption spectroscopy. Plain Ag2S nanocrystals and improved surface-passivated nanostructures were studied under different pump fluences and photon energies. Surface passivation significantly sharpens excitonic resonances, reducing defect-assisted recombination. Transient absorption spectroscopy reveals that the excited state dynamics are dominated by trapping and exciton recombination at low exciton densities, while fluence dependence studies reveal significant contributions from biexcitons and Auger recombination in all samples at high exciton densities. Notably, surface-passivated nanostructures exhibit faster multi-exciton recombination dynamics, highlighting the impact of effective surface passivation.
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