Tunable photoluminescence and site occupancy of activators Ce3+ in novel phosphors Ca3(1−x)ZrSi2O9:3xCe3+
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The novel Ce3+-activated blue-emitting phosphors Ca3(1−x)ZrSi2O9:3xCe were successfully obtained by solid-state reaction method in the air atmosphere. Two sets of individual photoluminescence spectra were observed in Ca3(1−x)ZrSi2O9:3xCe. In the two sets of spectra, the maximums of excitation and emission bands locate at about 324, 370 nm (denoted as spectra “EX:324, EM:370”) and 358, 410 nm (denoted as spectra “EX:358, EM:410”), respectively. By analyzing the crystal structure and photoluminescence spectra of Ca3(1−x)ZrSi2O9:3xCe, it can be concluded that the spectra “EX:324, EM:370” originated from Ce3+(1,3) ions occupying Ca2+(1) and Ca2+(3) sites, and the spectra “EX:358, EM:410” are due to Ce3+(2) ions occupying Ca2+(2) sites. Further, the emission band of Ca3(1−x)ZrSi2O9:3xCe is tunable, and the emission peaks red shift with the increase of excitation wavelength and Ce3+ doping concentration. The decay times of Ce3+ ions in Ca3(1−x)ZrSi2O9:3xCe phosphors are short in tens of nanoseconds. Moreover, the photoluminescence thermal stability of Ca3(1−x)ZrSi2O9:3xCe (x = 0.02) is acceptable, especially under the 324 nm excitation, and the relative emission intensity at 100 °C remains to be about 91% of the initial value at room temperature. Thus, Ca3(1−x)ZrSi2O9:3xCe is a kind of promising blue-emitting phosphors that can be potentially used in ultraviolet excited white light-emitting diodes (WLEDs), agriculture and other photonic fields.
The authors greatly thank the financial supports from the National Key Research and Development Program of China (Grant numbers 2016YFB0701004 and 2016YFB0700204), the National Natural Science Foundation of China (Grant number 51702343), the Natural Science Foundation of Shanghai (Grant number 16ZR1441100), and the Integrated Computing Materials Research Center of Shanghai Institute of Ceramics (Grant number Y51ZC8180G).