Chin‐Yiu Chan

Abstract By simple modification of the functional groups on the donor unit, the thermally activated delayed fluorescence (TADF) properties of emitters can easily be manipulated. A series of deep blue to blue emissive TADF derivatives is developed, capable of deep‐blue emissions from 403 to 460 nm in toluene. Deep‐blue organic light‐emitting diodes (OLEDs) based on this series of TADF emitters are fabricated, resulting in an electroluminescence peak at 428 nm and a high external quantum efficienc

Organic light-emitting diodes utilizing thermally activated delayed fluorescence is a potential solution for achieving stable blue devices. Sky-blue devices (CIE_y < 0.4) with high stability and high external quantum efficiency (>15%) at 1000 cd m^-2 based on either delayed fluorescence or phosphorescence are still limited and very hard to achieve simultaneously. Here, we report the design and synthesis of a new thermally activated delayed fluorescence emitter, 3Ph<sub>2</sub

Narrowband emissive multiresonant thermally activated delayed fluorescence (MR-TADF) emitters are a promising solution to achieve the current industry-targeted color standard, Rec. BT.2020-2, for blue color without using optical filters, aiming for high-efficiency organic light-emitting diodes (OLEDs). However, their long triplet lifetimes, largely affected by their slow reverse intersystem crossing rates, adversely affect device stability. In this study, a helical MR-TADF emitter (f-DOABNA) is

Abstract Multi‐resonance emitters (MREs) are a promising candidate for fulfilling the harsh requirements of display applications due to their unique photophysical properties. Recently, MREs have been widely used as a terminal emitter in hyperfluorescence organic light‐emitting diodes (HF‐OLEDs); however, since MREs are always thermally activated delayed fluorescence (TADF)‐active, possessing long triplet lifetimes in millisecond order, they result in severe chemical degradation. Instead of short

Organic light-emitting diodes (OLEDs) exhibiting thermally activated delayed fluorescence (TADF) have attracted great interest because of their excellent exciton harvesting ability in electroluminescence (EL). While TADF-OLEDs show a high EL efficiency, the device operational stability is not necessarily satisfactory for commercial applications. Herein, the isotope effect of the host material on the device operational stability in TADF-OLEDs is investigated. It is unveiled that the deuterated ho

A new class of hole-transporting spirothioxanthene derivatives has been synthesized and characterized. Their photophysical, electrochemical and thermal properties have been studied. These compounds exhibit high hole mobilities of up to 1 × 10–3 cm2 V–1 s–1, determined by using thin film transistor technique. In addition, these spirothioxanthene derivatives are promising donor materials in the construction of high performance organic photovoltaic (OPV) devices. With a very low dopant concentratio

Two new deep-blue narrowband multi-resonant emitters, 1B-DTACrs and 2B-DTACrs, one of which shows thermally activated delayed fluorescence (TADF), based on boron, nitrogen, and oxygen doped nanographenes are reported. Devices based on 2B-DTACrs showed an EQE_max of 14.8% and CIE coordinates of (0.150, 0.044), which are very close to the BT.2020 requirement for blue pixels.

A series of heterocyclic spiro derivatives has been successfully synthesized and characterized by photophysical and electrochemical studies. Taking advantage of their excellent hole-transporting properties, highly efficient small-molecular organic photovoltaic devices based on these heterocyclic compounds as donors with very low dopant concentrations have been prepared; particularly, a high open-circuit voltage of up to 1.10 V and a power conversion efficiency of up to 5.12% have been realized.

A new class of non-planar and three-dimensional spirobifluorene-modified perylene diimide compounds has been successfully designed and synthesized. The functionalization of the perylene diimide core with different spirobifluorene moieties can alter the molecular geometry as well as extend the spectral coverage into the red region. In addition, these compounds can be utilized as donor materials in combination with fullerene to form bulk heterojunctions, and particularly efficient organic photovol

This work reports a new acceptor for constructing donor-acceptor type (D-A type) blue thermally activated delayed fluorescence (TADF) emitters with narrowed charge-transfer (CT) emissions. A new acceptor core, carbazole-2-carbonitrile (CCN), is formed by the fusion of carbazole and benzonitrile. Three D-A type TADF emitters based on the CCN acceptor, namely 3CzCCN, 3MeCzCCN, and 3PhCzCCN, have been successfully synthesized and characterized. These emitters show deep-blue emissions from 439 to 45

Organic long persistent luminescence (OLPL) materials, with their hour-long afterglow, hold great promise across numerous applications, yet their performance lags behind that of inorganic counterparts. A deeper understanding of the underlying photophysical mechanisms, particularly the effective control of radical intermediates, is essential for developing high-performance OLPL materials; while systematic studies on the intrinsic stability of radical intermediates and their impact on OLPL perform

Abstract Luminescent boron‐nitrogen (BN)‐type multi‐resonance (MR) materials have been first reported by Hatakeyama and co‐workers in 2016. BN‐type MR materials have attracted a lot of attention, because of their unique photophysical properties, including narrowband emissions, high photoluminescent quantum yields, and thermally activated delayed fluorescent (TADF) properties. BN‐type MR‐TADF materials are considered as the next‐generation luminescent materials for efficient, stable, and narrow‐e

Organic Light-Emitting Diodes A deuterated host (PYD2Cz-d16) is introduced in the blue and green thermally activated delayed fluorescence organic light-emitting diodes (TADF-OLEDs). By using this deuterated host, the lifetime of the TADF-OLEDs is extended as presented by Chin-Yiu Chan, Chihaya Adachi, and co-workers in the article number 2000057. Such improvements could be attributed to the non-crystalline and densely packed behaviors of the film state in deuterated host, resulting in much more