Large area organic solar cells with thick and transparent protection layers

10 cm(2) area molecular photovoltaic cells have been fabricated, incorporating transparent protection layers of naphthalene tetracarboxylic anhydride (NTCDA) which completely suppress electrical shorting. Even a 2-mu m-thick NTCDA layer was unable to degrade cell performance. This technique will offer a solution to fabricate organic solar cells of sufficient area for practical applications.