Aqueous Spray Pyrolysis of Cu₂O Films: Influence of Reducing Agent and Acetic Acid Addition

Abstract

Cu2O is attractive as abundant and low‐cost material for energy‐related applications. This study investigated the versatile spray pyrolysis of Cu2O films from aqueous solutions. The appropriate deposition temperature and amount of copper acetate in the sprayed precursor solution was determined in order to eliminate unwanted copper oxide phases. It was shown that the addition of a reducing agent containing primary/secondary OH‐groups with suitable decomposition properties is necessary in order to obtain copper in the +I oxidation state. The influence of the pH value, determined by the addition of acetic acid to solutions containing varying reducing agents, on the structural film properties, was investigated. D‐sorbitol is for the first time proposed as suitable reducing agent to obtain compact and thick (ca. 500 nm) Cu2O films with an optical band gap of 2.3 eV.

Accelerated screening of Cu–Ga–Fe oxide semiconductors by combinatorial spray deposition and high-throughput analysis

“…Established recipes for water-based spray pyrolysis of Cu 2 O 29 and Ga 2 O 3 , 30 and a modified version of the latter one are followed to prepare the precursor solutions:…”

Numerical investigations of the impact of buffer germanium composition and low cost fabrication of Cu2O on AZO/ZnGeO/Cu2O solar cell performances

“…Besides the well known limitations induced by the interfacial defects at the junction and the loss of conversion efficiency inherent to low absorber thickness of Cu 2 O thin film photovoltaics, a strong control of the defect distribution in the absorber layer is a key parameter to improve Cu 2 O photovoltaic performances obtained by spray pyrolysis. For instance, one source of defects induced by the spray pysolysis process was very recently suggested by Plankensteiner et al [20] as impurities in the absorber layer resulting from the incomplete pyrolysis reaction of the glucose oxidizer used in the precursor solution.…”

“…However, the efficiency of the devices grown by spray pyrolysis is still limited below 1%. In order to improve the performances of metal oxide solar cells obtained by spray pyrolysis, further optimisation of the elaboration process has to be done by decreasing impurities levels in the material [20] or prevent unwanted copper oxide phases at the junction interface. The latter issue is well known for Cu 2 O heterojunctions [21].…”