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Novel three-dimensional YVO 4 :Ln3+ (Ln3+ = Eu3+, Sm3+, Dy3+, Tm3+) hierarchitectures were successfully fabricated on glass substrate by a simple, hydrothermal process by using disodium ethylenediaminetetraacetic acid (Na 2 H 2 L, where L4− = (CH 2 COO) 2 N(CH 2) 2 N(CH 2 COO) 2 4−)) as a capping agent. The shape and size of product can be tailored by controlling the reaction time and the Na 2 H 2 L/Y3+ molar ratio. As a typical morphology, YVO 4 :Eu3+ shows a flower-like hiearchitecture, which is composed of a primary microrod trunk and a large number of secondary nanonails. The trunk is a rectangle prism with a length of 2 μm. The nanonail branch has a length of 400 nm and a diameter of 80 nm, and its cap has a diameter of 100 nm with a thickness of 20 nm. A possible formation mechanism of this flower-like hierarchical structure was proposed, and it is investigated in detail through time evolution experiments. Under UV radiation, the thin film samples were shown the emission characteristic of Eu3+ (5D 0 →7F 2 , 618 nm), Dy3+ (4F 9/2 → 6H 13/2 , 575 nm), Sm3+ (4G 5/2 → 6H 7/2 , 603 nm), Tm3+ (1G 4 →3H 6 , 478 nm), and morphology-sensitive photoluminescent properties. Image 1 • Flower-like YVO 4 :Ln3+ hierarchitectures were synthesized by hydrothermal method. • The formation mechanisms of different microstructures were proposed. • The as-prepared products show morphology-sensitive photoluminescent properties. [ABSTRACT FROM AUTHOR]

Employing the short-chain C 4 H 9 NH 3 X (X = Cl, Br, I) compound as the unique capping agent, highly quality CH 3 NH 3 PbX 3 (X = Cl, Br, I) perovskite quantum dots can be synthesized at room temperature in the open air, which possess high photoluminescence quantum yields and tunable emission in the range of 440–660 nm. Besides, C 4 H 9 NH 3 Br can also improve the morphology of CH 3 NH 3 PbBr 3 thin films by spin-coating the N, N -dimerthylformamide solution of CH 3 NH 3 Br, C 4 H 9 NH 3 Br and PbBr 2 , making the thin film dense and compact, and improving its optical properties. Image 1 [ABSTRACT FROM AUTHOR]

The flower-like GdVO 4 :Ln 3+ ( Ln 3+ =Eu 3+ , Dy 3+ , Sm 3+ , Tm 3+ ) hierarchitectures have been successfully synthesized on a glass slide substrate through a one-pot hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na 2 H 2 L, where L 4- =(CH 2 COO) 2 N(CH 2 ) 2 N(CH 2 COO) 2 4- ). A high density and ordered flower-like GdVO 4 :Ln 3+ hierarchitectures grew epitaxially on glass substrate. The as-prepared flower-like architectures with the size about 6 μm are constructed by the numerous radially oriented single-crystalline nanorods with the width from 20 nm to 200 nm and the length from 500 nm to 3 μm. The morphologies, the thickness, and the density of as-grown flower clusters can be readily tuned by tailoring the growth time and Na 2 H 2 L/Gd 3+ molar ratio. The possible formation mechanism of flower-like GdVO 4 :Ln 3+ hierarchitectures is discussed on the basis of the results from the controlled experiments under hydrothermal conditions. Because of an energy transfer from vanadate groups to dopants, the flower-like GdVO 4 :Ln 3+ ( Ln 3+ =Eu 3+ , Dy 3+ , Sm 3+ and Tm 3+ ) superstructures showed strong characteristic dominant emissions of the Eu 3+ , Dy 3+ , Sm 3+ and Tm 3+ ions at 617 nm ( 5 D 0 → 7 F 2 , strong red), 575 nm ( 4 F 9/2 → 6 H 13/2 , yellow), 604 nm ( 4 G 5/2 → 6 H 7/2 , orange-red) and 476 nm ( 1 G 4 – 3 H 6 , blue) under ultraviolet excitation, respectively.Further, the emission color of the product can also be tuned by selecting the dopant Ln 3+ with characteristic emissions and varying the concentration ratio of co-doping activators. This approach could be extended to the fabrication of hierarchical structures for other oxide micro/nanomaterials, and may provide a general way to achieve multicolor-tunable emission for many applications. [ABSTRACT FROM AUTHOR]