Transparent nickel selenide alloy counter electrodes for bifacial dye-sensitized solar cells exceeding 10% efficiency

Abstract

In the current work, we report a series of bifacial dye-sensitized solar cells (DSSCs) that provide power conversion efficiencies of more than 10% from bifacial irradiation. The device comprises an N719-sensitized TiO₂ anode, a transparent nickel selenide (Ni–Se) alloy counter electrode (CE), and liquid electrolyte containing I⁻/I₃⁻ redox couples. Because of the high optical transparency, electron conduction ability, electrocatalytic activity of Ni–Se CEs, as well as dye illumination, electron excitation and power conversion efficiency have been remarkably enhanced. Results indicate that incident light from a transparent CE has a compensation effect to the light from the anode. The impressive efficiency along with simple preparation of the cost-effective Ni–Se alloy CEs highlights the potential application of bifacial illumination technique in robust DSSCs.