Bandgap Tunable Oxynitride LaNb2O7–xNx Nanosheets. Issue 12 (15th January 2023)

• Record Type: Journal Article
• Authors: Hsu, Chu‐Wei; Miyano, Takuro; Awaya, Keisuke; Tsushida, Masayuki; Hatakeyama, Kazuto; Koinuma, Michio; Ida, Shintaro
• Is Part Of: Small. Volume 19:Issue 12(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-15
• Subjects: 2D oxynitrides -- bandgap -- dielectric properties -- photocatalytic properties -- proton conductivity; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202206552
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Bandgap tunable lanthanum niobium oxynitride [LaNb2 O7‐x Nx ] (1+x)− nanosheet is prepared by the delamination of a Ruddlesden−Popper phase perovskite oxynitride via ion−exchange and two−step intercalation processes. The lanthanum niobium oxynitride nanosheets have a homogeneous thickness of 1.6 nm and exhibit a variety of chromatic colors depending on the nitridation temperature of the parent‐layered oxynitride. The bandgap energy of the nanosheets is determined by ultraviolet photoemission spectroscopy, Mott–Schottky, and photoelectrochemical measurements and is found to be tunable in the range of 2.03–2.63 eV. Furthermore, the oxide/oxynitride superlattice structures are fabricated by face−to−face stacking of 2D crystals using oxynitride [LaNb2 O7‐x Nx ] (1+x)− and oxide [Ca2 Nb3 O10 ] − nanosheets as building blocks. Moreover, the superlattices‐like restacked oxynitride/oxide nanosheets hybrid exhibits unique proton conductivity and dielectric properties strongly influenced by the oxynitride nanosheets and enhanced photocatalytic activity under visible light irradiation. Abstract : Oxynitride [LaNb2 O7‐x Nx ] (1+x)− nanosheets exhibit a variety of chromatic colors and bandgap energy tunable properties from 2.03 to 2.63 eV. Moreover, well−ordered oxynitride/oxide superlattice films are fabricated using monolayer [LaNb2 O6.8 N0.2 ] 1.2– and [Ca2 Nb3 O10 ] − nanosheets. The bandgap tunable [LaNb2 O7‐x Nx ] (1+x)− nanosheets are expected to open up new possibilities and boost the development of functional devices using oxynitride materials.