An effective three-photon IR quantum cutting excited by visible light used for solar cells, which has attracted broad attention of academia recently, is reported for the first time (to our knowledge). It is based on a single species of rare-earth Er3+ ion of Er0.3Gd0.7VO4 crystalline. It was found that the approximate quantum cutting efficiency of the 1532.5 nm 4I13/2-->4I15/2 fluorescence, when the 2H11/2 level was excited, is about 178.55%.

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A long lasting green phosphorescence was found in -doped calcium aluminate glasses prepared under a strongly reducing atmosphere. An electron-trapped centre giving an EPR signal at g = 1.999, an analogue of the centre in CaO, was induced by illumination with ultraviolet (uv) radiation and decayed slowly after the illumination was stopped. A partial oxidation of ions to ions by uv illumination was observed. A mechanism of the long lasting phosphorescence was suggested to consist of recombination of an electron released thermally from the -like centre with the photo-oxidized .

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