Postfabrication annealing of pentacene-based photovoltaic cells

We studied the effects of postfabrication annealing on heterojunction photovoltaic cells made from vacuum deposited pentacene and C-60. The maximum power conversion efficiency under 115 mW/cm(2) illumination increases from 0.45% to 1.07% after annealing the cells at 200degreesC. The increased performance is a result of better molecular ordering, which leads to an increased shunt resistance and built-in potential. (C) 2004 American Institute of Physics.