High Voc upon KF Post-Deposition Treatment for Ultrathin Single-Stage Coevaporated Cu(In, Ga)Se2 Solar Cells

• DOI: 10.1021/acsaem.9b01370
• Publication Date: 2019-07-19T20:52:23Z
• Authors: Jessica de Wild; Dilara Gokcen Buldu; Thomas Schnabel; Marcel Simor; Thierry Kohl; Gizem Birant; Guy Brammertz; Marc Meuris; Jef Poortmans; Bart Vermang
• Keywords: Passivation; Open-circuit voltage; Deposition; p–n junction

A simplified Cu(In, Ga)Se2 (CIGS) solar cell structure based on a 500 nm thin CIGS layer is presented. The absorber layers are grown with single-stage coevaporation process, and various KF post-deposition treatments (KF-PDT) performed. KF-PDT leads to an efficiency increase from 7% 12%. For all cells in open circuit voltage (Voc) fill factor measured, which attributed improved pn junction. By changing the annealing conditions, additional Voc measured. This reduction of light-induced defects at CIGS/CdS interface addition confirmed by reduced sub band gap emission photoluminescence spectra, increased decay time, quasi Fermi level splitting. With SCAPS results simulated, it concluded that after limited 640 mV due recombination back contact. higher can then only be achieved applying passivation back. There no indications process limiting efficiency, revealing potential proposed importance interfaces for ultrathin cells.