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The N-deficient porous g-C3N4 with broadband white light emission was constructed by supramolecular copolymerization design, which combined organic copolymers cyanuric acid and 2,4,6-triaminopyrimidine with melamine upon the mixture gas environment of (95%)­N2/(5%)­H2. Herein, we achieved great breakthrough in narrowing the band gap of g-C3N4 from 2.64 to 1.39 eV. Furthermore, in contrast to pristine g-C3N4, we demonstrated that the emission wavelengths of N-deficient porous g-C3N4 can be tuned from narrow blue to broadband white range, where the optimal white light coordinate position is (0.297, 0.345). The prepared N-deficient porous g-C3N4 overcomes the limitation of the narrow adjusting range of optical properties while using conventional g-C3N4 and makes it more promising for applications in solid-state displays.

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Er3+ doped Y2O3 and Nb2O5 modified germanate glasses with different Er3+ concentrations were prepared. J-O intensity parameters were computed to estimate the structural changes due to the additions of Y2O3 and Nb2O5. The main mid-infrared spectroscopic features were investigated. To shed light on the observed mid-infrared radiative behavior, 975 nm and 1.53 μm emission spectra along with their decay lifetimes were also discussed. Moreover, the energy transfer processes of 4I11/2 and 4I13/2 level were quantitatively analyzed. In view of the experimental lifetimes, the simplified rate equation was utilized to calculate the energy transfer upconversion processes of upper and lower laser level of 2.7 μm emission. The theoretical calculations are in good agreement with the observed 2.7 μm fluorescence phenomena. Finally, the stimulated emission and gain cross sections were calculated and the results indicate that Er3+ doped germanate glasses have great potential for mid-infrared application.