Multi-conformational Luminescence and Phosphorescence of Few Phenazine 1,2,3-triazole Molecules

Abstract

Dropcast lms produced from blends solutions of phenazine 1,2,3-triazole molecules in very low concentrations in a 1,3-Bis (N-carbazolyl) benzene (mCP) matrix were investigated at room temperature. The mCP acts as an optically inert matrix, having no in uence on the emission properties of the guest molecules. Its conductive properties also ensure that blend lms, within a completely organic character, are formed as truly active layers. The uorescent and phosphorescent emission properties of the phenazine molecules, depending on their conformational states, allowed relatively intense emissions in blue, green, red and also in white, without the need to mix different materials. Although the results of absorption of the blended lms have shown no characteristics of the guest molecules, due to their relatively low concentrations, the excitation of them occurs directly by the incident laser beam. The steady-state spectroscopy for the monomer and dimer singlet uorescence states of respective blue and green emissions of the lms were investigated. The analysis of their temporal decays were done using a different approach based on the Exponentially Modi ed Gaussian (EMG) function. The phosphorescent emissions of the triplet steady-states, occurring in the orange or in the red wavelength regions, were observed to be correlated, respectively, to the formation of guest monomers or to the guest dimers singlet states. I -IntroductionSimple molecular structures of phenazine have been studied since the 1960s [1-5]. Its relatively weak uorescence was mainly due to the decay of its singlet levels to triplet levels via an intersystem crossing (ISC). New phenazine derivative structures with relatively intense uorescent properties have been synthesized and were very useful as probes in a biological environment [6][7][8][9]. In this sense, the 1,2,3triazole phenazine molecule, the same as used in this work, proved to be effective as a selective metal probe, detecting cadmium ions that are extremely harmful to human health [10]. In addition to demonstrate their usefulness as a metal sensor, the 1,2,3-triazole phenazine molecules, also allowed the observation of an intense phosphorescent emission at room temperature.