Converting Conventional Host to TADF Sensitizer and Hot‐Exciton Emitter in Donor‐Adamantane‐Acceptor Triads for Blue OLEDs: A Computational Study

Abstract

Exploiting triplet excitons in TADF sensitizers and hot‐exciton emitters has attracted considerable attention and interest in recent studies on the design and development of blue OLEDs. The structural and optical property relationship of adamantane (Ad) core appended with four different strengths of donor and seven acceptor units were investigated using DFT and TD‐DFT methods. The theoretical studies revealed that increased donor and acceptor strength on adamantane building block leads to: (i) a decrease in ionization potentials and an increase in electron affinities, (ii) a decrease in singlet energies (ES) and the S1‐T1 energy gaps (∆EST); (iii) decreased SOC magnitudes between S1‐T1 states; (iv) increased RISC rate from the Tn to S1 states, demonstrating an increased tendency for upconversion of triplet excitons from the Tn to S1 state. In addition, low exchange energy causes excited state characteristics of molecules to shift from HLCT to CT nature in the S1 state. In contrast, the T1 states retain their LE character, resulting in higher triplet energies (ET). The adamantane molecular systems appended with P‐DMAC‐Donor‐Ad‐P‐DMB and Donor‐Ad‐P‐BODIPY based triads exhibit promising TADF sensitizer and hot‐exciton characteristics to find application as potential candidates for blue OLEDs when compared to experimentally reported conventional host.

Combined DFT and QM/MM Modeling on Multifunctional TADF Sensitizers and Hot-Exciton Emitters via Carborane Triads for Blue Hyperfluorescent OLEDs

“…The benchmark investigation demonstrates that the HOMO energies align closely with experimentally calculated values for the B3LYP, PBE0, and M06 functionals, while the LUMO energies show minimal deviations with the BP86, O3LYP, and B3LYP functionals. Despite the inherent theoretical challenges in calculating virtual orbitals of organic molecules, the B3LYP functional was selected for ground state optimization due to its ability to compute both HOMO and LUMO energies with minimal deviations, which numerous research studies have substantiated. , Adiabatic ionization potential (IP) and electron affinity (EA) calculations were performed using the neutral and ionic geometries of the molecules . Furthermore, an excited state benchmark study was undertaken employing various hybrid B3LYP, PBE0, and meta-hybrid M06, M06-2X, M06-HF, and range-separated CAM-B3LYP, LC-WPBE, and WB97X functional (Table S3 and Figure S3).…”

Enhancing Fast RISC in Hot‐Exciton Thermally Activated Delayed Fluorescence Emitter Through Fused Ring Modification: A Theoretical Insights

“…The key benefit related to the hot exciton mechanism is due to the occurrence of a higher lying transition rate, therefore, the T 1 state accumulation is reduced. [ 33–35 ] This successfully prevents annihilation caused by the T 1 excitons, with better device stability. By implementing the above design strategy, in 2012, Ma and co‐workers developed a TPA‐PPI, a new fluorescent D‐A type material, that utilizes triphenylamine (TPA) as an electron donor and phenanthroimidazole (PPI) as an electron acceptor.…”