Room Temperature Phosphorescence Lifetime and Spectrum Tuning of Substituted Thianthrenes

A group of thianthrene derivatives has been studied to investigate the effect of different substituents and substitution positions on their photophysical behavior. Strong room temperature phosphorescence (RTP) and dual fluorescence-phosphorescence at room temperature (RT-DFP) have been observed. Compounds with efficient (Φ ≈ 0.4) yellow and long-lived (τ = 88 ± 6 ms) green phosphorescence have been characterized. The involvement of nπ* and ππ* states was evaluated to explain their high triplet formation yield and phosphorescent properties. To give an insight into electron properties of studied molecules cyclic voltammetry and DFT calculations have been performed

Electrochromic Properties of Novel Selenophene and Tellurophene Derivatives Based on Carbazole and Triphenylamine Core

The 2,7- and 3,6-substituted carbazole and triphenylamine chalcogenophene (Se, Te) derivatives and their electrodeposited polymers are investigated using electrochemical and UV–vis–NIR/ESR spectroelectrochemical methods. Major differences in the case of oxidation and electropolymerization behavior between monomers and related polymers are shown. Se and Te atoms do not conjugate their lone electron pairs with the π-conjugated system and therefore only increase the contribution of the quinoid form of the chalcogenophene unit. The 2,7- substituted carbazole derivatives present stronger carbazole–chalcogenophene conjugation than 3,6-substituted derivatives. One 3,6-substituted carbazole derivative and triphenylamine derived polymers were found to have promising electrochromic properties with black electrochromism

Thermally Activated Delayed Fluorescence with Narrow Emission Spectrum and Organic Room Temperature Phosphorescence by Controlling Spin-Orbit Coupling and Phosphorescence Lifetime of Metal-Free Organic Molecules

This work shows a study of two organic molecules with very similar, large singlet-triplet gap of which one is a TADF emitter and the other an RTP emitter. By investigation of photophysical properties of these compounds, it is possible to explain their distinct behavior. Properties are studied in non-polar polymer and OLED host with further device fabrication. Furthermore, this work presents a CT TADF emitter that shows narrow and resolved electroluminescence (FWHM of 53 nm). The study presents efficient RTP emitter based on the D-D-D structure and also a first acridone-based TADF emitter of D-A-D structure

Observation of Dual Room Temperature Fluorescence-Phosphorescence in Air, in the Crystal Form of a Thianthrene Derivative

Thianthrenes have been nearly forgotten as phosphors in recent years, but are now coming back, showing their strong potential in luminescent applications. Here, we present a comprehensive photophysical study of a carbazolyl derivative of thianthrene in different matrices and environments. The diffusion of oxygen is slowed down in the rigid environment of thianthrene organic crystals suppressing their phosphorescence quenching, as well as triplet-triplet annihilation. This facilitates the observation of simultaneous fluorescence and phosphorescence emissions at room temperature, in air, giving origin to strong white luminescence. Moreover, the color coordinates of the dual fluorescence-phosphorescence white emission, which is observed only in rigid amorphous media and in crystals, can be tuned