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The exploration of new red phosphors is important for the development of white light-emitting diodes (w-LEDs), as existing red phosphors exhibit low efficiency and low performance. This work aims to enhance the photoluminescence characteristics of a red-emitting Gd2Zr2O7:Eu3+ phosphor by co-doping with Al3+. Eu3+ single-doped and Eu3+ and Al3+ co-doped Gd2Zr2O7 nanophosphors that could be efficiently pumped by commercial near-UV LED chips were prepared by a modified liquid–solid–solution phase-transfer method. X-ray diffraction data revealed that the synthesized phosphors were well crystallized with single-phase fluorite structure. Scanning electron microscopy images showed that the particle size ranges from 15 to 25 nm. In addition, the optical performance of the samples was characterized by fluorescence spectroscopy and lifetime spectroscopy. The effect of Al3+ on the luminescence performance of the Eu3+-doped Gd2Zr2O7 phosphor was studied in detail. The emission intensity of the Gd1.93Zr1·97O7:Eu3+0.07Al3+0.03 phosphor was found to be 620% stronger than that of the single-doped Eu3+ phosphor. These results unambiguously show that the Gd1.93Zr2-xO7:Eu3+0.07Al3+x phosphors are promising candidates for application in w-LEDs.

Previous reports found Al-doped ZnO nanosheets were formed at a certain preparation condition, but the formation mechanism was vague. In this work, we prepare sol-gel Al-doped ZnO films, and find that films show the obvious nanorods structure on surface of pure ZnO, but the nanorods changes to nanosheets gradually with rising doping concentration. The formation mechanism of nanosheets is clarified, and the doping concentration dependence of morphology is discussed in this paper. In addition, the photoluminescence spectra of all films appear a series of emissions including the near band edge emission (NBE) at 388 nm and several defect emissions (DE) at 396–499 nm. Previous reports proposed that NBE and DE would rise monotonously or decline monotonously with doping. However, this work reveals that the NBE decreases firstly in the range of low doping concentrations and then improves upon excessive doping concentration, due to crystalline quality and optical energy gap --- this reason is different from traditional explanations. Also, DE at different positions show the different variation trends, without the same increase or the same decrease. At excessive doping concentration, both NBE and DE enhance, illustrating the potential application for the enhanced ultraviolet and white light emitting devices.