| The objectives of this research project are improving the power conversion efficiency (PCE) of traditional bulk hetorojunction organic photovoltaic flat panel devices and the introduction of novel photovoltaic device architecture, the stack architecture, with a prospect of enhanced PCE. Complementary measurements on solid-state blends of P3HT (Poly(3-hexylthiophene-2,5-diyl)) with the soluble fullerene derivative PC61BM (1-(3-methoxycarbonyl) propyl-1-phenyl [6,6]C61) and PC7IBM, spin cast from chlorobenzene solution, have been performed to investigate the properties of thin film composites. The electronic characterization was done with UV-Vis absorption and photoluminescence spectroscopy while charge mobility was investigated with dark and photo conductivity measurements. The solar cell devices were characterized with current-voltage (I-V) measurements. Different electrode geometries were generated using E-beam and thermal evaporation with respective shadow masks. The morphology of the active layer of the photovoltaic device was tailored using thermal and solvent annealing to induce enhanced phase separation in the thin film blends. The angular dependency of the stack device was performed by rotating it with respect to the incoming light during the I-V measurements. Encapsulation was utilized to prolong the life time of the photovoltaic devices while they were measured inside an inert and dry environment. |
