Effects of cd diffusion and doping in high-performance perovskite solar cells using CdS as electron transport layer

Journal Article (Journal Article)

Perovskite solar cells with stabilized power conversion efficiency exceeding 15% have been achieved, using a methylammonium lead iodide (MAPbI3) absorber and CdS as the electron transport layer. X-ray photoelectron spectroscopy reveals a small presence of Cd at the surface of most perovskite films fabricated on CdS. Perovskite films were deliberately doped with Cd to understand the possible impacts of Cd diffusion into the perovskite absorber layer. Doping substantially increases the grain size of the perovskite films but also reduces device performance through the formation of an electrical barrier, as inferred by the S-shape of their J-V curves. Time-resolved photoluminescence measurements of the doped films do not indicate substantial nonradiative recombination due to bulk defects, but a secondary phase is evident in these films, which experiments have revealed to be the organic-inorganic hybrid material methylammonium cadmium iodide, (CH3NH3)2CdI4. It is further demonstrated that this compound can form via the reaction of CdS with methylammonium iodide and may form as a competing phase during deposition of the perovskite. Buildup of this insulating compound may act as an electrical barrier at perovskite interfaces, accounting for the drop in device performance.

Full Text

Duke Authors

Cited Authors

  • Dunlap-Shohl, WA; Younts, R; Gautam, B; Gundogdu, K; Mitzi, DB

Published Date

  • August 4, 2016

Published In

Volume / Issue

  • 120 / 30

Start / End Page

  • 16437 - 16445

Electronic International Standard Serial Number (EISSN)

  • 1932-7455

International Standard Serial Number (ISSN)

  • 1932-7447

Digital Object Identifier (DOI)

  • 10.1021/acs.jpcc.6b05406

Citation Source

  • Scopus