1. Zentrum für Sonnenenergie‐ und Wasserstoff‐Forschung Baden‐Württemberg, Industriestra?e 6, 70565 Stuttgart, Germany;2. Zentrum für Sonnenenergie‐ und Wasserstoff‐Forschung Baden‐Württemberg, Industriestra?e 6, 70565 Stuttgart, GermanyPhone: +00 49 711 7870 220, Fax: +00 49 711 7870 230
Abstract:
Alkali‐free Cu(In,Ga)Se2(CIGS) absorbers grown on Mo‐coated alumina (Al2O3) substrates were doped with potassium (K) after CIGS growth by a potassium fluoride (KF) post‐deposition treatment (PDT). The addition of K to the absorber leads to a strong increase in cell efficiency from 10.0% for the K‐free cell to 14.2% for the K‐doped cell, mainly driven by an increase in the open‐circuit voltage Voc and the fill factor FF, and to an increase in the net charge carrier density. Hence K doping by KF‐PDT is comparable to doping with Na.
