Electrochemical Characterization of CuSCN Hole-Extracting Thin Films for Perovskite Photovoltaics

• DOI: 10.1021/acsaem.9b00496
• Publication Date: 2019-05-24T19:30:01Z
• Authors: Ladislav Kavan; Zuzana Vlčková Ži...; Pavel Hubík; Neha Arora; M. Ibrahim Dar; Shaik M. Zakeeruddin; Michael Grätzel
• Keywords: Open-circuit voltage

CuSCN thin films (optimized previously for perovskite photovoltaics) are deposited on glass, F:SnO2 (FTO), Au, glass-like carbon (GC), and reduced graphene oxide (rGO). They exhibit capacitive charging in an electrochemical window from ca. −0.3 to 0.2 V vs Ag/AgCl. Outside this window, film is prone chemical structural changes. Anodic breakdown (at 0.5 V) causes restructuring into submicrometer particles denuding of the substrate. The natural p-doping demonstrated by both Hall effect Mott–Schottky plots impedance. corresponding flatband potentials (in Ag/AgCl) varied with substrate type as follows: 0.12 (CuSCN@FTO), 0.08 (CuSCN@Au), −0.02 (CuSCN@GC), 0.00 (CuSCN@rGO). acceptor concentrations determined impedance spectroscopy orders magnitude larger than those electrical conductivity effect, latter being regarded correct. Raman spectra confirm that thiocyanate dominating motif over isomeric isothiocyanate. In situ spectroelectrochemistry discloses substrate-specific intensity changes upon charging. blocking function tested a newly designed redox probe, Ru(NH3)63+/2+. It not only has appropriate potential testing but also avoids complications standard "ferrocyanide test" which normally used purpose. solar cells better conversion efficiency, fill factor, open-circuit voltage rGO-containing devices, ascribed driving force hole injection rGO.