Copper-based halide films with high photoluminescence quantum yield in the visible region deposited in situ by double source aerosol-assisted chemical vapor deposition

Abstract

A huge family of luminescent low-dimensional metal halides for optoelectronic applications has emerged recently as a green alternative to the highly toxic lead halide phosphors. To date, studies on the controlled deposition of these materials as films to be integrated into optoelectronic architectures remain scarce. Here, the synthesis and characterization of highly luminescent films of copper halide phosphors with emissions in violet: K2CuCl3, blue: Cs5Cu3Cl6I2, and green: Cs3Cu2Cl5 are reported. The films were obtained by multisource aerosol-assisted chemical vapor deposition (AACVD) from methanolic solutions at low temperature and under ambient conditions. Photoluminescent quantum yield values obtained for the films deposited on quartz substrates have values of 52% for K2CuCl3, 85% for Cs5Cu3Cl6I2, and 99% for Cs3Cu2Cl5. These values were highly influenced by the substrate since for samples deposited on glass substrates the values are 26.17% for K2CuCl3, 60.47% for Cs5Cu3Cl6I2, and 59.7% for Cs3Cu2Cl5. Different textured morphologies, with valuable applications in light-harvesting, were found for each stoichiometry. Finally, x-ray photo-emitted spectroscopy was employed to demonstrate the existence of only Cu(I) highly emissive species, suggesting that AACVD could be an excellent alternative for metal halide film deposition.