Colloidal semiconductor nanostructures demonstrate favorable tuning of the optoelectronic properties facilitated by quantum confinements. The interpretation understanding and optimization of experimental features and trends in photoluminescence of nanostructures is often guided by computational modeling at atomistic level. Two important factors provide contribution to efficiency, quantum yield, and lineshape of PL signal in photoexcited colloidal nanostructures: (a) cascading process of cooling of hot carriers, due to dissipation of electronic excitation energy to lattice vibrations and (b) distribution of transition energy and oscillator strength in an ensemble, also related to exciton-to-phonon coupling, providing quantitative way to assess thermal broadening of the PL lineshape. [1] The first principles modeling demonstrated correlation between temperature and PL lineshape of Si-quantum dots [2]. The radiative and nonradiative relaxation and multi-exciton processes in MAPbI quantum dots are all found to be affected by quantum confinement, that positively affects PLQY. [3] For quantum dots composed of heavy elements, such as CsPbBr3 colloidal quantum dots, the spin-orbit interaction found to provide additional splitting between transitions energies of states involved in PL and affect rates and efficiencies of the PL. [4] Deviation of nanoparticles from spherical shapes towards elongated nanorods and nanowires provides specific spectral signatures, especially for materials that carry indirect gap feature in bulk form.<br/><br/>

First-principles modeling of photoluminescence of colloidal nanostructures

2019 Fall National Meeting

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