1416881-50-9Relevant articles and documents
Simultaneous enhancement of efficiency and stability of OLEDs with thermally activated delayed fluorescence materials by modifying carbazoles with peripheral groups
Zhang, Yunge,Zhang, Dongdong,Tsuboi, Taiju,Qiu, Yong,Duan, Lian
, p. 393 - 402 (2019)
Albeit their high efficiencies, the operational stability of the organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters is still far from satisfaction, and few strategies have been proposed to improve their
Spectroscopic and TDDFT studies on the charge-transfer properties of metallated Octa(carbazolyl)phthalocyanines
Majeed, Shereen A.,Ghazal, Basma,Nevonen, Dustin E.,Nemykin, Victor N.,Makhseed, Saad
, (2019)
Four novel phthalocyanine complexes containing carbazole moieties were synthesized and characterized by 1H & 13C NMR, IR, and UV–visible spectroscopies, magnetic circular dichroism (MCD), elemental analysis, matrix-assisted laser desorption ionization mass spectrometry (MALDI), and X-ray crystallography. In all new compounds, characteristic interligand charge transfer transitions were observed in the 400–600 nm range and are indicative of interligand charge transfer transitions. The electrochemical and spectroelectrochemical methods used to probe the redox properties of 2–5 suggested phthalocyanine-centered first oxidation and reduction processes. Photophysical measurements of the prepared complexes in different solvents exhibited interesting properties due to the charge transfer effect and consequently prolonged excited state lifetime (5.00 ns) with high singlet oxygen quantum yield (ФΔ = 0.825) were acquired. Due to their remarkable solvatochromism phenomena and enhanced photo-related properties, the presented compounds have high potential in chemo-sensors and optical limiting material applications.
Thermal switches between delayed fluorescence and persistent phosphorescence based on a keto-BODIPY electron acceptor
Liu, Hui,Xue, Jiaying,Wang, Sisi,Wu, Fan,Zhao, Yue,Shen, Zhen
, p. 2030 - 2037 (2021)
A new type of twisted donor-acceptor molecular material3aand3bcontaining carbazole as an electron donor and keto-BODIPY bearing keto-isoindolinyl and pyridyl subunits as an acceptor has been prepared and characterized. Chemical modifications at themeso-position of keto-BODIPY with a nitrogen atom and a cyano group enhance the electron withdrawing ability and cause the emission color change from blue to yellow and red. Steady-state absorption and emission spectra of the two compounds show a strong intramolecular charge transfer (ICT) character. Time-resolved emission spectra and transient decay curves of3aand3bshow efficient delayed fluorescence with a lifetime of 12.64 μs for3aand 16.59 μs for3bat room temperature, whereas persistent phosphorescence with a lifetime of 576.65 ms for3aand 273.76 ms for3bwas obviously detected at 77 K. These photophysical behaviors have been fully revealedviaX-ray diffraction analysis and theoretical calculations, and thus attributed to the hybridized local and charge-transfer (HLCT) states and increased spin-orbital coupling (SOC) strength by mixed n → π* and π → π* transitions involving heteroatom lone pairs and the π-conjugated skeleton, respectively.
Highly efficient organic light-emitting diodes from delayed fluorescence
Uoyama, Hiroki,Goushi, Kenichi,Shizu, Katsuyuki,Nomura, Hiroko,Adachi, Chihaya
, p. 234 - 238 (2012)
The inherent flexibility afforded by molecular design has accelerated the development of a wide variety of organic semiconductors over the past two decades. In particular, great advances have been made in the development of materials for organic light-emitting diodes (OLEDs), from early devices based on fluorescent molecules to those using phosphorescent molecules. In OLEDs, electrically injected charge carriers recombine to form singlet and triplet excitons in a 1:3 ratio; the use of phosphorescent metal-organic complexes exploits the normally non-radiative triplet excitons and so enhances the overall electroluminescence efficiency. Here we report a class of metal-free organic electroluminescent molecules in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up-conversion from non-radiative triplet states to radiative singlet states while maintaining high radiative decay rates, of more than 10 6 decays per second. In other words, these molecules harness both singlet and triplet excitons for light emission through fluorescence decay channels, leading to an intrinsic fluorescence efficiency in excess of 90 per cent and a very high external electroluminescence efficiency, of more than 19 per cent, which is comparable to that achieved in high-efficiency phosphorescence-based OLEDs.
A Fully Automated Continuous-Flow Platform for Fluorescence Quenching Studies and Stern–Volmer Analysis
Kuijpers, Koen P. L.,Bottecchia, Cecilia,Cambié, Dario,Drummen, Koen,K?nig, Niels J.,No?l, Timothy
, p. 11278 - 11282 (2018)
Herein, we report the first fully automated continuous-flow platform for fluorescence quenching studies and Stern–Volmer analysis. All the components of the platform were automated and controlled by a self-written Python script. A user-friendly software allows even inexperienced operators to perform automated screening of novel quenchers or Stern–Volmer analysis, thus accelerating and facilitating both reaction discovery and mechanistic studies. The operational simplicity of our system affords a time and labor reduction over batch methods while increasing the accuracy and reproducibility of the data produced. Finally, the applicability of our platform is elucidated through relevant case studies.
Tailorable carbazolyl cyanobenzene-based photocatalysts for visible light-induced reduction of aryl halides
Ou, Wei,Zou, Ru,Han, Mengting,Yu, Lei,Su, Chenliang
supporting information, p. 1899 - 1902 (2019/12/27)
Herein, a series of carbazolyl cyanobenzene (CCB)-based organic photocatalysts with a broad range of photoredox capabilities were designed and synthesized, allowing precise control of the photocatalytic reactivity for the controllable reduction of aryl halides via a metal-free process. The screened-out CCB (5CzBN), a metal-free, low-cost, scalable and sustainable photocatalyst with both strong oxidative and reductive ability, exhibits superior performance for both dehalogenation and C[sbnd]C bond-forming arylation reactions.
