Over the past few decades, organic light-emitting diodes (OLEDs) find applications in smartphones, televisions, and the automotive sector. However, this technology is still not perfect, and its application for lighting purposes has been slow. For further development of the OLEDs, we designed twisted donor-acceptor-type electroactive bipolar derivatives using benzophenone and bicarbazole as building blocks. Derivatives were synthesized through the reaction of 4-fluorobenzophenone with various mono-alkylated 3,3′-bicarbazoles. We have provided a comprehensive structural characterization of these compounds. The new materials are amorphous and exhibit suitable glass transition temperatures ranging from 57 to 102 °C. They also demonstrate high thermal stability, with decomposition temperatures reaching 400 °C. The developed compounds exhibit elevated photoluminescence quantum yields (PLQY) of up to 75.5% and favourable HOMO-LUMO levels, along with suitable triplet-singlet state energy values. Due to their good solubility and suitable film-forming properties, all the compounds were evaluated as blue TADF emitters dispersed in commercial 4,4′-bis(N-carbazolyl)-1,10-biphenyl (CBP) host material and used for the formation of emissive layer of organic light-emitting diodes (OLEDs) in concentration-dependent experiments. Out of these experiments, the OLED with 15 wt% of the emitting derivative 4-(9′-{2-ethylhexyl}-[3,3′]-bicarbazol-9-yl)benzophenone exhibited superior performance. It attained a maximum brightness of 3581 cd/m², a current efficacy of 5.7 cd/A, a power efficacy of 4.1 lm/W, and an external quantum efficacy of 2.7%.

The demand for synthesizing highly luminescent compounds has emerged as a pivotal necessity in order to facilitate cost-effective and metal-free production of organic light-emitting diodes (OLEDs) on a commercial scale. This investigation introduces a readily soluble, electron deficient S-annulated perylene bisimide (PBI-S^ST) bearing swallow tails, exhibiting a room temperature columnar hexagonal mesophase with a low clearing point, and high photoluminescence quantum yield, thus making it a promising candidate for efficient OLEDs. Leveraging the luminescent properties of PBI-S^ST, a series of OLED devices were fabricated. PBI-S^ST was employed as the sole emitter and also incorporated at concentrations of 0.2, 0.5, and 1 wt% in CBP as the host material. Impressively, doped devices employing the compound at 0.2 wt% concentration within the host material CBP displayed an exceptional external quantum efficiency (EQE) of 6.5%. A maximum EQE of 11.6% was observed with 0.5 wt% PBI-S^ST in CBP, accompanied by a luminance of 1420 cd m⁻². This notable increase in EQE can be ascribed to energy transfer between the host and guest materials, as well as a hybridized local charge transfer (HLCT) process. The substantial enhancement in EQE marks a significant advancement in the application of multifunctional columnar self-assembled materials for OLED development.

This study investigates the enhancement of organic light-emitting diode (OLED) performance through the integration of titanium dioxide (TiO₂) nanocomposites within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) matrix. The nanocomposite films were prepared using a controlled dispersion of TiO₂ belts into the PEDOT/PSS solution, followed by their incorporation into the OLED hole-injection layer (HIL). Our results demonstrate a significant improvement in device efficiency, attributed to the optimized charge carrier mobility and reduced recombination losses, which were achieved by the presence of TiO₂. The nanocomposite hybrid layer enhances light emission efficiency due to its role in modifying surface roughness, promoting better film uniformity, and improving hole injection. The incorporation of TiO₂ nanobelts into PEDOT/PSS led to significant efficiency enhancements, yielding a 39% increase in PE_max, a 37% improvement in CE_max, and a remarkable 72% rise in EQE_max compared to the undoped counterpart. This research provides insight into the potential of TiO₂ nanocomposites in advancing OLED technology for next-generation display and lighting applications.