SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 36: Transport properties
HL 36.6: Vortrag
Donnerstag, 30. März 2023, 11:15–11:30, POT 151
Energy transfer between Si quantum dots and protoporphyrin molecules as a function of distance, orientation and size — •Athanasios Koliogiorgos1 and Tomas Polcar2 — 1Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic — 2Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Czech Republic
Organic molecules such as protoporphyrin IX (PPIX) can be attached to bulk or nanostructured silicon to enhance its optical and electronic properties. In this study, the interaction between PPIX molecules (donor) and Si nanocrystals (acceptor) up to 2.5 nm for varying distances and orientations is studied by DFT, semi-empirical and TDDFT methods. Simulations show an effect on electronic structure, indicative of electron charge transfer in parallel orientation and very small distances and non-electron energy transfer for different orientations and larger distances. An absorption-emission spectral overlap is observed. We use the Transition Density Cube method to calculate the electronic couplings and energy transfer rates between donor and acceptor. The Si quantum dots with the smallest size yield larger couplings than the larger nanocrystals. The coupling is enhanced by adding a plasmon nanoparticle as a bridge between donor and acceptor. Results using Au nanoparticles show increased energy transfer rates up to four orders of magnitude and lower distance dependence.