Youichi Tsuchiya

Near-IR organic light-emitting diodes (NIR-OLEDs) are potential light-sources for various sensing applications as OLEDs have unique features such as ultra-flexibility and low-cost fabrication. However, the low external electroluminescence (EL) quantum efficiency (EQE) of NIR-OLEDs is a critical obstacle for potential applications. Here, we demonstrate a highly efficient NIR emitter with thermally activated delayed fluorescence (TADF) and its application to NIR-OLEDs. The NIR-TADF emitter, TPA-PZ

The photophysical analysis of thermally activated delayed fluorescence (TADF) materials has become instrumental for providing insights into their stability and performance, which is not only relevant for organic light-emitting diodes but also for other applications such as sensing, imaging, and photocatalysis. Thus, a deeper understanding of the photophysics underpinning the TADF mechanism is required to push materials design further. Previously reported analyses in the literature of the kinetic

Organic light‐emitting diodes (OLEDs) displaying a wide range of emission colors with emission peaks from 450 to 665 nm using a single emitting material, avobenzone boron difluoride (AVB‐BF 2 ), are reported. Color tuning is achieved by controlling the aggregation of AVB‐BF 2 and the formation of a “triadic” exciplex of an AVB‐BF 2 dimer and a host molecule. Various electroluminescent devices containing AVB‐BF 2 cover the whole visible light spectrum and a white‐emitting device with CIE coordina

Abstract Thermally activated delayed fluorescence (TADF) emitters induced by the multiple resonance (MR) effect have garnered considerable attention. However, it is difficult to develop MR‐TADF emitters that maintain high color purities in the red region. In this work, the importance of excited state alignments of MR‐based donor‐acceptor (D‐A) molecules in determining their preferring characteristics is clarified. By using the newly designed molecule m BDPA‐TOAT whose apparent excited states sho

Abstract With the aim of achieving high‐performance thermally activated delayed fluorescence, a series of trioxoazatriangulene derivatives are systematically developed by modifying the donor substituents. The emission colors are shifted from green to greenish‐yellow and to yellow with rather broad spectral widths of 70–95 nm by introducing carbazole, triphenylamine, or diphenylamine donor units, indicating that each emission originates from a charge‐transfer transition. On the other hand, the tr

Highly efficient blue and green thermally activated delayed fluorescence (TADF) molecules bearing trifluoromethane-modified carbazole groups were developed. The trifluoromethane groups on carbazole induced blue-shifted emission and improved the photoluminescence quantum yield. The photostability of the TADF molecules was strongly related to the modification position of trifluoromethane on carbazole.

A sensitive detection and identification method for beer spoilage organisms was developed. The procedure involves the electrophoretic analysis of DNA fragments amplified by the polymerase chain reaction. When genomic DNA of Lactobacillus brevis was amplified, using a set of primers, to give a 117-base pair fragment encompassing the 5S rRNA gene (rDNA) and then electrophoretically analyzed, a single cell of L. brevis was detected. When various populations of L. brevis were added to 250-ml volumes

"Detection of Lactobacillus Brevis in Beer Using Polymerase Chain Reaction Technology." Journal of the American Society of Brewing Chemists, 51(1), pp. 40–41

In Nature, chromophoric groups play various roles, such as oxygen carriers, electron donors, light sensitizers, which are achieved in many cases by control of their aggregation modes in proteins. Host-guest chemistry between cyclodextrins and porphyrins has attracted great interest from supramolecular chemists because of their unique structures and functions that mimic those of proteins with chromophoric prosthetic groups. To mimic Nature's contrivances, the host-guest systems between cyclodextr

Organic nanoparticles (O-dots) with a high photoluminescence quantum yield (94%) and long-lived delayed emission (3.1 μs) originating from thermally activated delayed fluorescence (TADF) were developed as glassy state particles using an oil in water emulsion under high pressure (<20 bar). The TADF glassy O-dots exhibit not only good dispersibility and high photostability in water but also good uptake properties into living cells. The glassy O-dots will open new uses as organic emitters in biolog

Quantum chemical calculations are necessary to develop advanced emitter materials showing thermally-activated delayed fluorescence (TADF) for organic light-emitting diodes (OLEDs). However, calculation costs become problematic when more accurate functionals were used, therefore it is judicious to use a multimethod approach for efficiency. Here we employed combinatorial chemistry <i>in silico</i> to develop the deep blue TADF materials with a new concept of homo-junction design. The homo-junction