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Deep‐red and near‐infrared emitters with twisted donor–acceptor (D–A) structures often exhibit suboptimal performance in organic light‐emitting diodes (OLEDs) due to constraints imposed by the energy gap law. In this work, a pure hydrogen carbon (PHC) host material named SBF‐DTP is purposefully tailored for deep‐red OLEDs. The excellent capacity of SBF‐DTP to support D–A type DR emitters effectively arises from its distinctive attributes: localized excitation states, 3D configuration, and low polarity. When employing SBF‐DTP as the host for the fluorescence emitter DCPA‐TPA and the thermally activated delayed fluorescence emitter APDC‐DTPA, doped films exhibit substantially enhanced photoluminescence quantum yields. This improvement leads to high‐efficiency OLEDs with external quantum efficiencies of 5.47% for DCPA‐TPA and 20.03% for APDC‐DTPA, respectively, which is about twice as high as the initial reports. This findings underscore the paramount significance of developing efficient host materials in the pursuit of high‐performance deep red and even near‐infrared OLEDs. [ABSTRACT FROM AUTHOR]

Organic light-emitting diodes (OLEDs) with high-definition displays require narrowband emission from each pixel. Recently, boron-based thermally activated delayed fluorescence (TADF) emitters have gained broad attention in the OLED research field. They can effectively utilize both singlet and triplet excitons for electroluminescence, resulting in a small full width of half maximum (FWHM). The fused nitrogen/boron (N/B) system, known as the multi-resonance TADF (MR-TADF) system, has been making rapid progress. In this review, we summarize the current research progress in both traditional and MR-type boron derivatives with TADF characteristics from a molecular construction perspective. We discuss the molecular design strategy involved in maintaining high device efficiency and simultaneously achieving a narrowband emission profile. This review aims to provide insight and guidance for future developments for improving the stability, color purity, and performance of boron-based materials. [ABSTRACT FROM AUTHOR]

Carbonyl‐containing derivatives show enduring vitality in the field of thermally activated delayed fluorescence (TADF) materials; they can realize high device efficiency by using both singlet and triplet excitons for electroluminescence. Recently, a system based on fused ketone/amine exhibited huge potential for constructing multi‐resonance TADF (MR‐TADF) emitters, which exhibit higher narrow‐band emission than conventional TADF emitters with twisted donor‐acceptor (D‐A) structure. Herein, we summarize current research progress in both traditional and MR‐type ketone derivatives with TADF characteristics for introducing the molecular design strategy of maintaining high device efficiency while keeping narrow‐band emission profile. We hope this review can inspire the emergence of more high‐performance narrow‐band materials. [ABSTRACT FROM AUTHOR]

Gravity mura is a typical defect in large-sized LCD which causes non-uniform shades at underside. In this investigation, a mechanical model was proposed and analyzed under gravity and thermal expansion. The stiffness and arrangement of photospacers were considered in this model. Furthermore, the simulation results were obtained to modify the analytical model properly. The analytical results facilitated the establishment of the design criteria of LCD cells for which the gravity mura could be restrained or eliminated. [ABSTRACT FROM AUTHOR]

Carbonyl-containing derivatives show enduring vitality in the field of thermally activated delayed fluorescence (TADF) materials; they can realize high device efficiency by using both singlet and triplet excitons for electroluminescence. Recently, a system based on fused ketone/amine exhibited huge potential for constructing multi-resonance TADF (MR-TADF) emitters, which exhibit higher narrow-band emission than conventional TADF emitters with twisted donor-acceptor (D-A) structure. Herein, we summarize current research progress in both traditional and MR-type ketone derivatives with TADF characteristics for introducing the molecular design strategy of maintaining high device efficiency while keeping narrow-band emission profile. We hope this review can inspire the emergence of more high-performance narrow-band materials., (© 2022 Wiley-VCH GmbH.)