Abstract
We report a study on solar cells using pentacene derivatives with triisopropylsilylethynyl substitution at the 6,13-position and 1,3-dioxolane substitution to the terminal benzenoid rings of pentacene as the electron donor and C-60 as the electron acceptor. A significant increase in the open circuit voltage (V-oc) was obtained in all the pentacene-derivative based cells with the highest V-oc as high as 0.90 V, compared to a 0.24 V value for pentacene. The variation in the V-oc of the cells is in qualitative agreement with the larger offset between ionization potential of the electron donor and the electron affinity Of C-60. The power conversion efficiency (eta) at 100 mW/cm(2) of EtTP-5/C-60 cells reached 0.74%, which is comparable to that of a pentacene/C-60 Cell (0.82%).