Efficient and Stable Planar n–i–p Sb2Se3 Solar Cells Enabled by Oriented 1D Trigonal Selenium Structures. Issue 16 (30th June 2020) - Shen, Kai
Abstract: Environmentally benign and potentially cost‐effective Sb2 Se3 solar cells have drawn much attention by continuously achieving new efficiency records. This article reports a compatible strategy to enhance the efficiency of planar n–i–p Sb2 Se3 solar cells through Sb2 Se3 surface modification and an architecture with oriented 1D van der Waals material, trigonal selenium (t‐Se). A seed layer assisted successive close spaced sublimation (CSS) is developed to fabricate highly crystalline Sb2 Se3 absorbers. It is found that the Sb2 Se3 absorber exhibits a Se‐deficient surface and negative surface band bending. Reactive Se is innovatively introduced to compensate the surface Se deficiency and form an (101) oriented 1D t‐Se interlayer. The p‐type t‐Se layer promotes a favored band alignment and band bending at the Sb2 Se3 /t‐Se interface, and functionally works as a surface passivation and hole transport material, which significantly suppresses interface recombination and enhances carrier extraction efficiency. An efficiency of 7.45% is obtained in a planar Sb2 Se3 solar cell in superstrate n–i–p configuration, which is the highest efficiency for planar Sb2 Se3 solar cells prepared by CSS. The all‐inorganic Sb2 Se3 solar cell with t‐Se shows superb stability, retaining ≈98% of the initial efficiency after 40 days storage in open air without encapsulation. Abstract : This work reports a compatible strategy to enhance the efficiency of planar n–i–p Sb2 Se3 solar cells through Sb2 Se3 surface modification and an architecture with oriented 1D van der Waals material, trigonal selenium (t‐Se). The p‐type t‐Se layer functionally works as a surface passivation and hole transport material. The all‐inorganic device structure enables high efficiency and superb stability.