Study on green synthesis and properties of luminescent material bis(8-hydroxyquinoline) calcium (CaQ2)

• Published in: Journal of luminescence Vol. 195; pp. 120 - 125
• Main Authors: Wu, Shiting, Zhong, Xueming, Zeng, Hongze, You, Wen, Zhou, Wei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2018
• Subjects: Bis(8-hydroxyquinoline) calcium; Green synthesis; Luminescence; Properties; Thermal stability; Green synthesis; Properties; Thermal stability; Bis(8-hydroxyquinoline) calcium; Luminescence
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2017.11.029

This work proposes a novel, effective and green synthesis method for bis(8-hydroxyquinoline) calcium (CaQ2) that can be directly used for organic electroluminescent materials. Cycle experiment shows that the utilization of raw materials was well improved. The influence of different synthesis conditions on the crystallinity and purity of the samples was studied through X-ray diffraction spectroscopy (XRD), which indicates that the product has excellent crystallinity and high purity. EDS pattern reveals that the sample contains elements of Ca, C, N and O. The structure was investigated by Fourier transform infrared absorption spectroscopy (FITR). Infrared absorption spectrum illustrates the Ca-O peak at 487cm−1 and the existence of the quinoline ring. The crystal morphologys obtained by different synthetic conditions were detected by SEM. Since only CaQ2-A had synthesized without adding any organic solvent which had blocks with smooth surface. Luminescence properties of CaQ2 compound were examined by fluorescence spectra at ambient temperature. The emission spectras of CaQ2 under different synthesis conditions were obtained under the excitation of 288nm excitation wavelength. Maximum emission wavelengths are 470nm, 466nm and 466nm, respectively. The decay lifetime of CaQ2 is 21.83ns which was obtained at 288nm excitation. The TG-DTA analysis shows that CaQ2 has a high thermal stability. •High-purity bis(8-hydroxyquinoline) calcium (CaQ2) was synthesized by a facile, efficient, green method.•With some good luminous properties, the CaQ2 is good candidate for excellent organic electroluminescent materials.•The properties of CaQ2 obtained without organic solvent is better than that obtained by adding an organic solvent.•The re-usable features of liquid filter has a potential commercial value for improving the utilization of raw materials obviously.