Speaker: Andrew V. Naumov
Topic: “Photonics of semiconductor quantum dots – Nobel Prize 2023”
Abstract:
The Nobel Prize in Chemistry 2023 was awarded for the discovery, research, and application of semiconductor quantum dots – nanocrystals with photophysical properties that depend on their size and morphology. Quantum dots exhibit photoluminescence and electroluminescence properties, as well as effective light conversion, which makes them widely used in various applications of modern photonics: LEDs, TV matrixes, solar cells. In addition, the characteristics of quantum dots luminescence are sensitive to local environment parameters, which makes them the basis of sensor devices for thermometry, bio- and medical diagnostics, and detector technology. At the level of individual quantum dots we can observe the amazing effect of photoluminescence flickering which allows us to directly observe and study the quantum properties of the microcosm.
Recent detailed reviews on the topic of quantum dots have been published in the journal Photonics:
1. Arzhanov A.I. et al., Photonics of semiconductor quantum dots: fundamental aspects // Фотоника (Photonics Russia), 15 (8), 622-640 (2021).
2. Arzhanov A.I. et al., Photonics of semiconductor quantum dots: applied aspects // Фотоника (Photonics Russia), 16 (2), 96-112 (2022).
Speaker: Alexander O. Savostyanov
Topic: “Wide-range cryogenic spectromicroscopy of single molecules in solid matrices: electron-phonon interaction and spectral diffusion”
Abstract:
Single fluorescent organic molecules embedded in optically transparent dielectric matrices are great interest for the development of new promising nanophotonic devices. These molecules have compact dimensions, allowed for generation single photons with high Debye-Waller factors at various wavelengths, are easy to manufacture with a desired spatial density, and are well compatible with the next-generation hybrid integrated circuits. At the same time, a number of fundamental problems related to the influence of phonons and tunneling systems on the optical-spectral properties of single molecules remain unresolved.
Experimentally, the excitation spectra of fluorescence and spectral trajectories of single molecules of tetra-tert-butylethylene and Mg-porphyrazines in thin polyisobutylene films were studied in a wide temperature (5 – 70 K) and spectral (up to 130 cm-1) range and analyzed within existing theoretical approaches. Experimentally, spectral diffusion was observed for the first time at distances up to 30 cm-1, and the effect of phonon wings in the spectra of individual molecules was discovered. A model of the interaction of impurity molecules with the local environment is proposed, which explains the observed temperature broadening of the spectra.