(26e) Effect of Uniquely Assembled Nanostructures on Photovoltaic Properties

This study focuses on the energy transfer and electron transport in the photovoltaic device with uniquely designed nanostructures of an acceptor/donor energy system and an electron carrier delivery system. Furthermore, the effect of both the assembled nanostructures of acceptor/donor energy delivery and the different morphology of nanomaterials on photovoltaic performance are studied.

Förster resonance energy transfer between the xanthene dye (donor of energy) and a new polymethine dye (acceptor of energy) was studied on the surface of TiO₂ films in DSSCs. The sensitization of semiconductor films by the donor acceptor compound leads to a doubling of energy conversion efficiency. Measurements show that this is due to the widening of photo sensitivity of the cell in the blue region of the spectrum. Increasing the total energy absorbed leads to increasing the number of generated charge carriers at the interface of TiO₂ and the dyes.

Zinc Oxide nanoarrays with rod and sheet morphologies were fabricated and assembled for electron transport study of the dye sensitized solar cells (DSSCs). A photoluminescence spectra study indicated that nanosheets had more defect density compared to nanorods, which resulted in a lower open circuit photovoltage. Electrochemical impedance spectroscopy (EIS) and dye absorption amount analysis further explained the high short-circuit current density (J_sc) of the DSSC with ZnO nanosheet structure, based on the dye-loading amount, effective electron lifetime, and electron density.