Liquid-junction cells with thin-film CuInSe2

Abstract

Thin films (n type) of CuInSe₂ have been successfully adapted for use in liquid‐junction photoelectrochemical (PEC) cells. The best films, of 4‐μm thickness, showed 5.9% solar conversion efficiency and no degradation for over 15 kC cm⁻², the most stable performance to date for thin‐film PEC systems. Some 2‐μm depth from the surface is affected by the iodine‐based electrolyte, forming a p‐type chemical film with a heterojunction interface and stabilized by saturating the electrolyte with CuI. The latter appears to be an important component of the chemical film.