A novel fluorophore with multichromic effect and its application in LED light for the volatile vapor detection

Successfully designed and synthesized diaryl maleimide DAM, and their structure was confirmed by mass spectroscopy and NMR techniques. They investigated their photophysical properties, such as solvatochromic and the aggregation effect of AIE/ACQ on the water/DMF ratio, and other studies of solid-state mechanofluorochromic, such as grinding, exposure to solvent fumes, hydrostatic pressures, and vapochromic. Interestingly, the solvent methods gave very similar results in both the dissolving phase and the vapor phase. For the solution state from hexane to CH₂Cl_2, a greenish-yellow to orange emission was observed. From hexane to dichloromethane, naked-eye colorimetric changes (from yellow to orange in a solid state) were observed. Very interesting results were obtained, the yellow solid was ground for 1 min, it turned into an orange color, and its wavelengths were red-shifted in both absorption and emission. Subsequently, the ground sample was exposed to diethyl ether vapors, which returned to the original green-yellow emission and absorption. The applied hydrostatic pressures (0-4Mpa) in DAM gave excellent red-shifted emission, and then their hydrostatic pressures were increased to 4-16 Mpa, and the red-shifted emission gradually decreased.

Triphenylamine/4,4'-Dimethoxytriphenylamine-Functionalized Thieno[3,2-b]thiophene Fluorophores with a High Quantum Efficiency: Synthesis and Photophysical Properties

A wide series of 10 new triphenylamine (TPA)/4,4'-dimethoxytriphenylamine (TPA(OMe)₂)-functionalized thieno[3,2-b]thiophene (TT) fluorophores, 4a-e and 5a-e, bearing different electron-donating and electron-withdrawing substituents (-PhCN, -PhF, -PhOMe, -Ph, and -C₆H₁₃) at the terminal thienothiophene units were designed and synthesized by the Suzuki coupling reaction. Their optical and electrochemical properties were investigated by experimental and computational studies. Solid-state fluorescent quantum yields were recorded to be from 20 to 69%, and the maximum solution-state quantum efficiency reached 97%. Moreover, the photophysical characterization of the novel chromophores demonstrated a significant Stokes shift, reaching 179 nm with a bathochromic shift. They exhibited tuning color emission from orange to dark blue in solution and showed fluorescence lifetime reaching 4.70 ns. The relationship between triphenylamine (TPA)/4,4'-dimethoxytriphenylamine (TPA(OMe)₂)-derived triarylamines and different functional groups on thieno[3,2-b] thiophene units was discussed.

Butterfly-Like Triarylamines with High Hole Mobility and On/Off Ratio in Bottom-Gated OFETs

Highly π-extended butterfly-shaped triarylamine dyads with aryleneethynylene spacer were constructed using an efficient synthetic route. These aryleneethynylene-bridged dyads are highly fluorescent and exhibited high HOMO levels, and low bandgaps, which are suitable for high-performance p-type OFETs. The field-effect transistors were fabricated through a solution-processable method and exhibited promising p-type performance with field-effect mobility up to 4.3 cm² /Vs and high I_on/off of 10⁸ under ambient conditions.

Operando direct observation of spin-states and charge-trappings of blue light-emitting-diode materials in thin-film devices

Spin-states and charge-trappings in blue organic light-emitting diodes (OLEDs) are important issues for developing high-device-performance application such as full-color displays and white illumination. However, they have not yet been completely clarified because of the lack of a study from a microscopic viewpoint. Here, we report operando electron spin resonance (ESR) spectroscopy to investigate the spin-states and charge-trappings in organic semiconductor materials used for blue OLEDs such as a blue light-emitting material 1-bis(2-naphthyl)anthracene (ADN) using metal–insulator–semiconductor (MIS) diodes, hole or electron only devices, and blue OLEDs from the microscopic viewpoint. We have clarified spin-states of electrically accumulated holes and electrons and their charge-trappings in the MIS diodes at the molecular level by directly observing their electrically-induced ESR signals; the spin-states are well reproduced by density functional theory. In contrast to a green light-emitting material, the ADN radical anions largely accumulate in the film, which will cause the large degradation of the molecule and devices. The result will give deeper understanding of blue OLEDs and be useful for developing high-performance and durable devices.

Unravelling the photophysics of triphenylamine and diphenylamine dyes: a comprehensive investigation with ortho-, meta- and para-amido substituted derivatives

This study reveals the intriguing solvent polarity dependent modulations in the photophysics of triphenylamine and diphenylamine based dyes.