Zhurong Mo,Yanping Huo,Haoyi Wu,Brij Mohan,Hongli Wen,Li Luo,Deshmukh Abdul Hakeem
We report the synthesis and the effect of synthesis temperature on the crystal structure and dual mode (DC/UC) luminescence properties of the NASE-1000–1300. Two different polymorphs, i.e., nepheline and carnegieite of the NASE have been prepared just by changing the annealing temperature. Multi wavelength excitation can be used to obtain different emissions in visible and NIR regions. Under 380 and 980 nm excitation, the NASE-1000–1300 produces 1535 nm NIR emission, whereas green and red visible emissions are observed with 980 and 808 nm laser excitations. Under 980 nm laser excitation, the synthesis temperature dependent nepheline and carnegieite polymorphs emit intense red and green emission, respectively. Two-photon process is responsible for the green and red UC emissions of the NASE-1300. The NASE-1000-1300 produces intense red emission under 808 nm laser excitation. We believe that the NASE-1000–1300 could be a promising candidate for the photonic as well as biological applications.
Optical anisotropy, a spatially asymmetric light–matter interaction that manifests itself as birefringence and dichroism, is paramount for manipulating light polarization in modern optics. So far, various natural birefringent crystals are widely used, but their birefringence is limited to <0.3. Here we demonstrate a solution-processable natural crystal C 3 H 8 N 6 I 6 ·3H 2 O with giant birefringence up to 2.8 within the visible to infrared spectral region. Combining critical point analysis and the first-principles calculations, we reveal that this giant optical anisotropy mainly comes from the linear (I 3 ) − structural units in a parallel arrangement, which maximizes the difference of polarizability along the different crystallographic axes. This work highlights the potential of natural polyiodide crystals as an outstanding platform to satisfy the increasing demand for photonic applications that exploit polarization in optical communication, three-dimensional imaging, ultrahigh-resolution sensing and other tasks.
危险品化学品经营许可证（带存储）