Photophysical Properties of Benzophenone-Based TADF Emitters in Relation to Their Molecular Structure

Abstract

Thermally activated delayed fluorescence (TADF) materials are commonly used in various apparatus, including organic light-emitting device-based displays, as they remarkably improve the internal quantum efficiencies. Although there is a wide range of donor–acceptor-based compounds possessing TADF properties, in this computational study, we investigated TADF and some non-TADF chromophores, containing benzophenone or its structural derivatives as the acceptor core, together with various donor moieties. Following the computational modeling of the emitters, several excited state properties, such as the absorption spectra, singlet–triplet energy gaps (Δ E ST ), natural transition orbitals, and the topological Φ S indices, have been computed. Along with the donor–acceptor torsion angles and spin-orbit coupling values, these descriptors have been utilized to investigate potential TADF efficiency. Our study has shown that on the one hand, our photophysical/structural descriptors and computational methodologies predict the experimental results quite well, and on the other hand, our extensive benchmark can be useful to pinpoint the most promising functionals and descriptors for the study of benzophenone-based TADF emitters.

Computational descriptor analysis on excited state behaviours of a series of TADF and non-TADF compounds

“…Prior to the evaluation of all optical and photophysical properties, conformational analysis was performed using the Gaussian 16 software package 76 to characterize all possible conformers of the chosen TADF and non-TADF molecules. Density Functional Theory (DFT) calculations with the M06-2X 77,78 meta-hybrid functional and the 6-31+G(d,p) 75 basis set have been carried out to optimize the ground state conformers and the corresponding S 1 and T 1 geometries. However, all conformers are expected to share the same TDA behavior since the latter is mainly dictated by the twisting angle between donor and acceptor moieties or between the donor and bridge moieties, which are highly conserved in the conformational space.…”

“…Our main goal in that contribution was to understand the photophysical properties of benzophenone emitters and their derivatives in terms of absorption spectra, charge separations in the excited states, Δ E ST gaps and SOC magnitude. 75 Here, on the other hand, we plan to extend the objectives of the previous study investigating TADF emitters with various acceptor moieties and propose a new, more general, computational strategy applicable to a large variety of TADF emitters. For this purpose, we analyzed the relationship between molecular structures and photophysical properties of a wide range of emitters by means of ab initio calculations.…”

Near‐Infrared Room‐Temperature Phosphorescence in Arylselanyl BODIPY‐Doped Materials

“…In this study, our interest in proposing NIR RTP materials led us to employ a host‐guest doping strategy [21] . Benzophenone ( BP ) which is widely used as a building block in OLED, [22] was selected as a host material with an efficient ISC channel [23] . Its low melting point is beneficial for the melt‐casting method [24] to prepare BODIPY‐doped crystalline materials.…”

An Efficient Approach to Pyrene‐based Aggregation‐induced Emission Luminogens

“…[18] Benzophenone is an important component in the design of thermally activated delayed fluorescence/ phosphorescent emitters for OLED devices, , [19], [20][21] due to its strong electronaccepting ability and efficient intersystem crossing. [22] Previously, Zhang et al combined triphenylamine and benzophenone to afford AIE-active room temperature phosphorescence luminophores. [23] More recently, Tang and coworkers reported a novel molecule, namely (4-(phenothiazin-10-yl)phenyl)(pyren-1yl)-methanone, which possesses AIE characteristics, polymorphism and mechanochromic properties.…”

“…Benzophenone is an important component in the design of thermally activated delayed fluorescence/ phosphorescent emitters for OLED devices, ,[19],[20][21] due to its strong electron‐accepting ability and efficient intersystem crossing [22] . Previously, Zhang et al combined triphenylamine and benzophenone to afford AIE‐active room temperature phosphorescence luminophores [23] .…”