Transition-metal activated phosphors are an important family of luminescent materials that can produce white light with an outstanding color rendering index and correlated color temperature for use in light-emitting diodes.

First published as an Advance Article on the webTwo photoluminescent two-and three-dimensional coordination polymers consisting of Zn 4 O [or Zn 4 (OH) 2 ] cores, dicarboxylate (isophthalate or fumarate) and 4,4A-bipyridine ligands as building blocks have been hydrothermally synthesized and structurally characterized.The construction of supramolecular architectures are currently of great interest owing to their intriguing network topologies and potential functions as new classes of materials. 1 Polynuclear d 10 metal (Cu I , Ag I , Au I , Zn II or Cd II ) complexes have been found to exhibit intriguing structural and photoluminescent properties. 2-5 We have been pursuing synthetic strategies for non-interpenetrating open frameworks with variable cavities or channels using simple units as building blocks. 6 We now extend to work towards extended networks based on metal clusters as building blocks, and report here the preparation and crystal structures of two novel coordination polymers constructed by zinc cluster cores, 4,4A-bipyridine (4,4A-bpy) and dicarboxylate ligands, namely [Zn 4 O(ip) 3 (4,4A-bpy)] (ip = isophthalate) 1 and [Zn 4 (OH) 2 (fa) 3 (4,4A-bpy) 2 ] (fa = fumarate) 2.

White light-emitting diodes (WLEDs) with high luminous brightness, low energy consumption, long lifetime and environmental friendliness can be applied in various fields. In order to improve the quality of white light, red phosphors are necessary.

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The Ce3+ → Tb3+ → Eu3+ energy-transfer process enables Eu3+5D0 → 7F J line emission to be sensitized by the allowed Ce3+ 4f1 → 5d1 absorption transition in near-ultraviolet (NUV) and violet spectral regions. This energy-transfer strategy is applied in Y2SiO5:Ce3+, Tb3+, Eu3+ powders, leading to line-emitting red phosphors that can be excited by short-wavelength InGaN LEDs. The blue, green, and red colors can be tuned by the ratio of Ce3+/Tb3+/Eu3+. Furthermore, the energy-transfer efficiencies and corresponding mechanisms are discussed in detail, and the thermal stability is evaluated. The results suggest that the optimal composition phosphor Y2SiO5: 0.01Ce3+, 0.50Tb3+, 0.01Eu3+, which exhibits an intense Eu3+ red 4f–4f sharp emission with a strong 4f–5d absorption band of Ce3+ at the NUV region, could serve as a potential broadband-excited and narrow line red phosphor for NUV LEDs.