Vacuum-Deposited Planar Heterojunction Polymer Solar Cells

The vacuum thermal evaporation of poly(3-hexylthiophene) (P3HT) for application in photovoltaic cells is demonstrated. Structural changes before and after evaporation are determined using GPC UV-vis absorption spectroscopy, NMR, and FTIR GPC showed that the polymer molecular weight is reduced during evaporation, leading to a blue-shift of the absorption spectra. FTIR and NMR were used examine the change in chemical 'structure it was found that conjugation remains mostly intact; however, the conjugation length decreases and side chains dissociate from the backbone Bilayer heterojunction solar cells were fabricated by sequential deposition of P3HT and C(60) and the photovoltaic response measure