RELAXATION DYNAMICS, IMPACT IONIZATION, AND CHARGE TRANSFER DYNAMICS OF EXCITONS IN QUANTUM DOTS: APPLICATIONS TO ULTRA-HIGH EFFICIENCY SOLAR PHOTON CONVERSION

摘要

Semiconductor quantum dots are shown to greatly modify the relaxation dynamics of hot electron-hole pairs. The cooling times of hot electron-hole pairs can be reduced by about one order of magnitude through a phonon bottleneck by blocking the Auger cooling channel and very efficient electron-hole pair multiplication can be achieved in small gap quantum dots. Up to 3 excitons/photon can be obtained in PbSe QDs at photon energies that are greater than 3,8 times the HOMO-LUMO energy. The application of these changes in hot electron-hole pair relaxation dynamics to high efficiency solar photon conversion is discussed.