Open AccessFormation of high-density CuBi2O4 thin film photocathodes with polyvinylpyrrolidone-metal interaction
Author(s) -
NamWoon Kim,
Byeong-Uk Choi,
Hyunung Yu,
Sangwoo Ryu,
Jihun Oh
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.00a171
Subject(s) - thin film , materials science , annealing (glass) , polyvinylpyrrolidone , nucleation , chemical engineering , porosity , silicon , nanotechnology , optoelectronics , composite material , chemistry , organic chemistry , polymer chemistry , engineering
We present a polymer-assisted spin coating process used to fabricate high-density p-type CuBi 2 O 4 (CBO) thin films. Polyvinylpyrrolidone (PVP) is introduced in the precursor solutions in order to promote uniform nucleation of CBO and prevent formation of the secondary phase, such as Bi 2 O 3, by Bi 3+ ion hydrolysis. Slow PVP molecule decomposition during the two-step annealing process, with a 1 M/0.5 M (Bi 3+ /Cu 2+ ) metal ion concentration, enables optimum contact at the CBO/substrate interface by avoiding formation of voids. This resulted in the formation of non-porous, compact CBO thin films. The highest current density of the photoelectrochemical (PEC) oxygen reduction reaction is obtained with non-porous, compact CBO thin films due to unimpeded charge transport through the CBO bulk, as well as across the interface. When combined with silicon, the high-density CBO thin film investigated in this work is expected to provide new PEC tandem cell options to use for solar applications.