Mg-doped C60 thin film as improved n-type organic semiconductor for a solar cell

Mg doping effect on a [2-methoxy, ${\text{5-(2}}^{\prime }-\mathrm{ethylhexyloxy})$ -1,4-phenylene-vinylene] $(\mathrm{MEH-PPV}{\mathrm{)/C}}_{60}$ bilayer solar cell has been investigated. We find that the Mg doping occurs during the deposition of the Mg top electrode onto the $C_{60}$ film and that the solar cell property is markedly improved by the doping. The power conversion efficiency of the Mg-doped device under $\text{100\hspace{0.17em}}{\mathrm{mW/cm}}^2$ white light illumination is 0.54%, which is approximately 400 times larger than that of the nondoped device.