Project: " Hot Carrier Solar Cell: Implementation of the Ultimate Pv Converter " Annual Report April 2009

The UNSW node of the Hot Carrier Solar Cell project is investigating the phonon dispersions properties of ordered quantum dot arrays. The object is to determine the potential to modify the allowed phonon energies such as to block the decay of optical phonons, this being the principle decay mechanism for hot photo-generated carriers in an absorber material. This will then offer the possibility of producing a material which substantially decreases the rate of carrier cooling in an absorber and hence allows carriers to be extracted whilst still hot and hence produce a higher external voltage. Thus also boosting the efficiency of such a ‘Hot Carrier solar cell’ very significantly. The investigation has two main themes: 1. Modelling of the phonon dispersions in three dimensions of these quantum dot nanostructures. This will allow the phonon properties of various material combinations to be modelled and assessed. 2. Fabrication of ordered quantum dot arrays. This is being carried out using colloidal dispersion of capped nanocrystals. Once fabricated these arrays will be characterised for both their modified phonon dispersions and their ability to slow the rate of carrier cooling.