Study of structural and optical properties of ZnAlQ₅ (zinc aluminum quinolate) organic phosphor for OLED applications

The various composition of ZnAlQ₅ such as Zn_1.5A_10.5Q₅, Zn₁Al₁Q₅, Zn_0.5Al_1.5Q₅ organic phosphors were prepared via simple cost effective co-precipitation method. The FTIR, SEM, photoluminescence analysis of the prepared phosphors were reported. ZnQ₂ and AlQ₃ were also prepared by similar method and their properties were compared with different composition of ZnAlQ₅. The structural elucidation in the form of stretching frequencies of chemical bonds of the prepared phosphor was carried out using Fourier Transform Infrared Spectroscopy (FTIR). The stretching frequency analysis confirms the formation of prepared phosphor materials. The SEM analysis shows the surface morphological behavior of prepared phosphor materials. Greenish photoluminescence were observed at 505 to 510 nm for the different composition of ZnAlQ₅,in which Zn_1.5Al_0.5Q₅ shows maximum luminescence intensity at 505 nm. PL emission of ZnQ₂ was observed at 515 nm, while for AlQ₃ at 520 nm. The blue shift of 10 nm was observed in Zn_1.5A_10.5Q₅ due to modification of energy level due to presence of Zn²⁺ and Al³⁺. The enhancement in PL intensity was observed in Zn_1.5A_10.5Q₅ compared to the other composition due to transfer of energy between Zn²⁺ and quinolate complex. Optical properties of the prepared materials were evaluated for possible applications in organic light emitting devices (OLED).