Crystalline Gaq3Nanostructures: Preparation, Thermal Property and Spectroscopy Characterization

Abstract

Crystalline Gaq31-D nanostructures and nanospheres could be fabricated by thermal evaporation under cold trap. The influences of the key process parameters on formation of the nanostructures were also investigated. It has been demonstrated that the morphology and dimension of the nanostructures were mainly controlled by working temperature and working pressure. One-dimensional nanostructures were fabricated at a lower working temperature, whereas nanospheres were formed at a higher working temperature. Larger nanospheres could be obtained when a higher working pressure was applied. The XRD, FTIR, and NMR analyses evidenced that the nanostructures mainly consisted of δ-phase Gaq3. Their DSC trace revealed two small exothermic peaks in addition to the melting endotherm. The one in lower temperature region was ascribed to a transition from δ to β phase, while another in higher temperature region could be identified as a transition from β to δ phase. All the crystalline nanostructures show similar PL spectra due to absence of quantum confinement effect. They also exhibited a spectral blue shift because of a looser interligand spacing and reduced orbital overlap in their δ-phase molecular structures.

Electroluminescent Guest@MOF Nanoparticles for Thin Film Optoelectronics and Solid‐State Lighting

“…For example, the FTIR spectrum of Gaq3@ZIF‐8 shows absorption bands above 1000 cm −1 characteristics of the vibrational modes of the hydroxyquinoline ligands in Gaq3, specifically the bands at 1460 cm −1 (quinoline CC/CN stretching + CH bending) and at 1500 cm −1 (pyridyl and phenyl CC/CN stretching + CH bending vibration). [ 38,39 ] Similarly, the FTIR spectrum of Gaq3@ZIF‐8 also displays characteristic bands of ZIF‐8 as the band at 1584 cm −1 (CN stretch mode) and the bands in the regions of 1350–1500 cm −1 (associated with the entire ring stretching) and 900–1350 cm −1 (in‐plane bending of the mIm ring). [ 40 ] This combination of FTIR features unequivocally confirms the presence of Gaq3 present in the framework of the ZIF‐8 host.…”

Effect of Surface Modification on the Absorption and Luminescence Response in tris(8-Hydroxyquinoline) Gallium Films Achieved by Thermal Treatment

“…It was increased to nearly five times stronger than that of untreated films at 235 o C. However, at 255 o C the luminescence intensity was quenched due to the crystalline region formation [20] (see Figure 3). It was reported that the luminescence behaviour is strongly related to the nature and structure of films [15,23]. Consequently, the variation in luminescence can be attributed to the morphological modifications which have been brought about the thermal treatment process under nitrogen gas.…”

Absorption and emission properties of 5‐phenyl tris(8‐hydroxyquinolinato) M(III) complexes (M = Al, Ga, In) and correlations with molecular electrostatic potential

“…The first efficient organic light emitting diode was constructed by Tang and VanSlyke at Kodak in 1987 with a double organic layer structure consisting of tris (8‐hydroxyquinolinato) aluminum (III) (Alq3) as emitter . Thereupon, Alq3 and other group III metal chelates of gallium and indium have received significant attention as electroluminescent materials due to their distinctive electron transport and emissive properties . In the Mq3 complex, the trivalent metal coordinates to three bidentate 8‐hydroxyquinolinate ligands (M[C 9 H 6 NO] 3 ) to give an octahedral configuration in two possible geometric isomers, meridional ( mer ) and facial ( fac ) (Figure ).…”