Electron-hole pairs or excitons are generated by electronic excitation from ground to excited electronic state. Exciton dissociation and generation of free charge carriers is central for light-harvesting applications of photoactive nanoparticles. This talk will focus on computational investigation of shape-based and heterojunction-based control of electron-hole binding and recombination in quantum dots, nanodisks, and nanorods. Results from a multi-faceted investigation on CdSe, CdS, PbS, PbSe, and CdSe/ZnS nanoparticles using a variety of metrics including exciton binding energy, electron-hole recombination probability, electron-hole separation distance, and electron-hole pair density will be presented. These quantities were computed by solving the electron-hole Schrodinger equation using the explicitly correlated Hartree-Fock (XCHF) method. The XCHF method is a variational method that uses a correlated electron-hole wavefunction that depends explicitly on the electron-hole interparticle distance. Investigation of optical properties of large finite-sized cluster is computationally challenging because of the large number of electrons in the system and the absence of translational symmetry. In the present work, we show that the pseudopotential+XCHF method provide a computationally efficient route for investigating electron-hole correlation in nanoparticles that are computationally prohibitive to be treated using pseudopotential+CI method. The talk will focus on the theoretical development of the XCHF method, techniques for efficient implementation, and comparison with other quasiparticle-based methods including Bethe-Salpeter equation, electron-hole variational Monte Carlo, and configuration interaction method.

Effect of shape, size, and heterojunction on excitonic interactions in semiconductor nanoparticles

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.