Nanosheet Seed-Layer Assists Oriented Growth of Highly Luminescent Perovskite Films

Oxide phosphors are attractive materials for various applications in optoelectronic devices due to their high chemical stability and efficient luminescent characteristics. As yet, however, the fabrication of high-quality luminescent thin films on a glass substrate remains challenging for practical implementation. Here, we report the efficient fabrication of highly oriented luminescent perovskite oxide films on a glass substrate using a monolayer film of oxide nanosheets as the seed layer. A densely packed monolayer film of Ca2Nb3O10 nanosheets was prepared by the Langmuir-Blodgett (LB) method, where hybridization of the cationic molecules and the Ca2Nb3O10 nanosheets produced stable LB films with large-area processability. Oriented thin films with a sharp and intense emission of Pr-0.002(Ca0.6Sr0.4)(0.997)TiO3 were successfully obtained on a glass substrate modified with a seed layer. Highly luminescent transparent films are producible on inexpensive noncrystalline substrates; this approach also enables large-area processing of high-quality thin-film phosphors.