Design, crystal growth and characterizations of novel bis morpholinium zinc bromide single crystals for optoelectronic applications

Abstract

A novel metal-organic third-order nonlinear optical (NLO) material with promising excellent properties in the crucial solar blind UV region. For the first time, high NLO active metal-organic complex of bis-morpholinium zinc bromide (BMZB) single crystal has been rationally designed and single crystals have been grown by slow evaporation solution technique (SEST). Remarkably, the grown crystal exhibits competitive and even superior physical properties including high thermal stability and wider transparency than the standard NLO single crystal. The title compound crystallizes in the monoclinic crystal system with the space group of P21/cc and four molecules are accumulated in the unit cell (unit cell parameters are a = 6.7860 (6) Å, b = 16.6239 (2) Å, c = 14.8875 (2) Å, β = 94.937 (3)° and Z = 4). Further, the phase purity and the crystallinity of the grown sample were analyzed through powder X-ray diffraction (PXRD) analysis. The Fourier transform infrared (FTIR) spectroscopy analysis has been used to determine the presence of multifarious functional groups in the grown crystal. The recorded optical transmittance spectrum reveals that the BMZB crystal possesses good optical transparency in the range between deep ultraviolet (UV) and near-infrared (NIR) regions. Intriguingly, the short cut-off edge of the grown crystal is found to be about 227 nm which is more favorable for developing modern photonic and optoelectronic devices in the solar blind UV region. The thermal and mechanical stabilities of the grown crystals have been studied using Vickers microhardness and thermogravimetry (TG) and differential thermal analysis (DTA) respectively. Moreover, key requirements for designing practical NLO devices such as large laser damage threshold (LDT) and excellent third-order NLO response have been observed in the grown single crystal. Therefore, our findings open up a new avenue to the rational design of thermally stable and large NLO active metal-organic complexes for practical NLO applications.