A heterojunction film of NiS2 and MnS as an efficient counter electrode for dye-sensitized solar cells

Abstract

Transition metal sulfides are an important alternative to Pt in dye-sensitized solar cells (DSSCs) to lower the cost and improve the stability. In this letter, we deposited NiS2/MnS and MnS/NiS2 heterojunction films on FTO as the counter electrode (CE) by pulsed laser deposition (PLD) and vapor-phase sulfurization. The heterojunction CE of NiS2/MnS can achieve a power conversion efficiency of 6.44 %, which is close to that of the Pt CE (6.84 %). The unique band gap structure of NiS2 and MnS in this heterojunction can accelerate the transport of electrons in the CE to improve the ability of electro-catalysis. This makes the heterojunction film composed of two inexpensive transition metal sulfides an ideal substitute for Pt film.