Temperature-dependent luminescence and second-harmonic generation of perovskite-type manganese and cadmium dicyanamide frameworks templated by tetrapropylammonium cations

Publication date: Available online 19 December 2019Source: Journal of Alloys and CompoundsAuthor(s): Mirosław Mączka, Dagmara Stefańska, Jan K. Zaręba, Marcin Nyk, Adam SieradzkiAbstractThis contribution is devoted to the linear and nonlinear optical studies of two three-dimensional (3D) perovskite-like metal-organic frameworks, [(C3H7)4N][Cd(N(CN)2)3] and [(C3H7)4N][Mn(N(CN)2)3]. Band gap energy (5.02 eV) of Cd-analogue is slightly smaller than that for its manganese counterpart (5.17 eV); values of energy gaps are determined from diffuse reflectance spectra. Upon ultraviolet excitation (266 nm) [(C3H7)4N][Cd(N(CN)2)3] exhibits intense bluish-white emission composed of two bands at 541 and 432 nm (at 80 K). Intensity of this emission decreases quickly with increasing temperature and the longer wavelength band exhibits strong blue-shift on heating to 250 K, followed by the red shift above this temperature. The Mn analogue features weaker red luminescence at 626 nm, which displays much smaller decrease in intensity on heating. Furthermore, chromaticity index of this emission shows a negligible change in the 80–350 K temperature range. Temperature-resolved second harmonic generation (TR-SHG) studies have been performed with the use of 800 nm fs laser irradiation to test the symmetry of room-temperature and high-temperature crystal phases. TR-SHG provided an ample evidence of the noncentrosymmetric nature of the room-temperature phases of both studied c...

Source: Journal of Alloys and Compounds - December 20, 2019 Category: Chemistry Source Type: research