[Preparation and spectral analysis of a new type of blue light-emitting material delta-Alq3].

In the present article, delta-Alq3, a new type of blue light-emitting material, was synthesized and investigated by IR spectra, XRD spectra, UV-Vis absorption spectra, photoluminescence (PL) spectra, and electroluminescence (EL) spectra. The relationship between molecular spatial structure and spectral characteristics was studied by the spectral analysis of delta-Alq3 and alpha-Alq3. Results show that a new phase of Alq3 (delta-Alq3) can be obtained by vacuum heating alpha-Alq3, and the molecular spatial structure of alpha-Alq3 changes during the vacuum heating. The molecular spatial structure of delta-Alq3 lacks symmetry compared to alpha-Alq3. This transformation can reduce the electron cloud density on phenoxide of Alq3 and weaken the intermolecular conjugated interaction between adjacent Alq3 molecules. Hence, the pi--pi* electron transition absorption peak of delta-Alq3 shifts toward short wavelength in UV-Vis absorption spectra, and the maximum emission peak of delta-Alq3 (lamda max = 480 nm) blue-shifts by 35 nm compared with that of alpha-Alq3 (lamda max = 515 nm) in PL spectra. The maximum emission peaks of delta-Alq3 and alpha-Alq3 are all at 520 nm in EL spectra.