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31.
Improved device reliability in organic light emitting devices by controlling the etching of indium zinc oxide anode
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A controllable etching process for indium zinc oxide (IZO) films was developed by using a weak etchant of oxalic acid with a slow etching ratio. With controllable etching time and temperature, a patterned IZO electrode with smoothed surface morphology and slope edge was achieved. For the practical application in organic light emitting devices (OLEDs), a sup- pression of the leak current in the current-voltage characteristics of OLEDs was observed. It resulted in a 1.6 times longer half lifetime in the IZO-based OLEDs compared to that using an indium tin oxide (ITO) anode etched by a conventional strong etchant of aqua regia. 相似文献
32.
Luminescence of complex ions is a general phenomenon; the number of such complexes in various electronic configurations found to show emission is increasing rapidly. For some it has been possible to assign the emission as phosphorescence or as fluorescence, for others the proper assignment is as yet not clear. 相似文献
33.
Dr. Zafar Mahmood Noreen Rehmat Prof. Shaomin Ji Prof. Jianzhang Zhao Shanshan Sun Dr. Mariangela Di Donato Prof. Mingde Li Maria Teddei Prof. Yanping Huo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):14912-14918
Zinc(II) bis(dipyrrin) complexes, which feature intense visible absorption and efficient symmetry breaking charge transfer (SBCT) are outstanding candidates for photovoltaics but their short lived triplet states limit applications in several areas. Herein we demonstrate that triplet excited state dynamics of bis(dipyrrin) complexes can be efficiently tuned by attaching electron donating aryl moieties at the 5,5′-position of the complexes. For the first time, a long lived triplet excited state (τT=296 μs) along with efficient ISC ability (ΦΔ=71 %) was observed for zinc(II) bis(dipyrrin) complexes, formed via SBCT. The results revealed that molecular geometry and energy gap between the charge transfer (CT) state and triplet energy levels strongly control the triplet excited state properties of the complexes. An efficient triplet–triplet annihilation upconversion system was devised for the first time using a SBCT architecture as triplet photosensitizer, reaching a high upconversion quantum yield of 6.2 %. Our findings provide a blueprint for the development of triplet photosensitizers based on earth abundant metal complexes with long lived triplet state for revolutionary photochemical applications. 相似文献
34.
The hydrohaloalkanes have attracted much attention as potential substitutes of chlorofluorocarbons (CFCs) that deplete the ozone layer and lead to great high global warming. Having a short atmospheric lifetime is very important for the potential substitutes that may also induce ozone depletion and yield high global warming gases to be put in use. Quantitative structure–activity relationship (QSAR) studies were presented for their lifetimes aided by the quantum chemistry parameters including net charges, Mulliken overlaps, E HOMO and E LUMO based on the density functional theory (DFT) at B3PW91 level, and the C-H bond dissociation energy based on AM1 calculations. Outstanding features of the logistic mapping, a simple chaotic system, especially the inherent ability to search the space of interest exhaustively have been utilized. The chaotic mapping aided genetic algorithm artificial neural network training scheme (CGANN) showed better performance than the conventional genetic algorithm ANN training when the structure of the data set was not favorable. The lifetimes of HFCs and HCs appeared to be greatly dependent on their energies of the highest occupied molecular orbitals. The perference of the RMSRE comparing to RMSE as objective function of ANN training was better for the samples of interest with relatively short lifetimes. C2H6 and C3H8 as potential green substitutes of CFCs present relatively short lifetimes. 相似文献
35.
This work aims at elucidating the mechanism of solvation of a radical ion pair (RIP) in a micro‐heterogeneous binary solvent mixture using magnetically affected reaction yield (MARY) spectroscopy. For the exciplex‐forming 9,10‐dimethylanthracene/N,N‐dimethylaniline system a comparative, composition‐dependent MARY line‐broadening study is undertaken in a heterogeneous (toluene/dimethylsulfoxide) and a quasi‐homogenous (propyl acetate/butyronitrile) solvent mixture. The half‐saturation field extrapolated to zero‐quencher concentration, B1/2, and the self‐exchange rate constants are analyzed in the light of solvent dynamical properties of the mixtures and a dielectric continuum solvation model. The dependence of B1/2 on the solvent composition is explained by cluster formation giving rise to shortened RIP lifetimes. The results are in qualitative agreement with the continuum solvation model suggesting that it could serve as a theoretical basis for quantitative modeling. 相似文献
36.
Fen Jin Yan Lian Jishan Li Jing Zheng Yaping Hu Jinhua Liu Jin Huang Ronghua Yang 《Analytica chimica acta》2013
A highly sensitive and selective fluorescence aptamer biosensors for the determination of adenosine triphosphate (ATP) was developed. Binding of a target with splitting aptamers labeled with pyrene molecules form stable pyrene dimer in the γ-cyclodextrin (γ-CD) cavity, yielding a strong excimer emission. We have found that inclusion of pyrene dimer in γ-cyclodextrin cavity not only exhibits additive increases in quantum yield and emission lifetime of the excimer, but also facilitates target-induced fusion of the splitting aptamers to form the aptamer/target complex. As proof-of-principle, the approach was applied to fluorescence detection of adenosine triphosphate. With an anti-ATP aptamer, the approach exhibits excimer fluorescence response toward ATP with a maximum signal-to-background ratio of 32.1 and remarkably low detection limit of 80 nM ATP in buffer solution. Moreover, due to the additive fluorescence lifetime of excimer induced by γ-cyclodextrin, time-resolved measurements could be conveniently used to detect as low as 0.5 μM ATP in blood serum quantitatively. 相似文献
37.
《Arabian Journal of Chemistry》2014,7(3):261-266
Effect of the micelles of anionic, cationic and non-ionic surfactants on the fluorescence quenching of 1- and 2-naphthols has been studied in the presence of copper ion. The excited state lifetime, dynamic and static quenching constants for these systems have been determined. Fluorescence quenching in water and SDS micelle is due to the collision of the fluorophore with the quencher with a small static component. The negatively charged naphtholate ions in the excited state are quenched with significantly higher rates than the neutral naphthol molecules, which are located further inside the mesophase. CTAB micelle is less effective than the SDS micelle for fluorescence quenching. The effect of CTAB on water-assisted excited-state deprotonation has been investigated in the presence of ZnSO4. For TX-100 micelle there is negligible quenching even at higher concentration of the quencher. 相似文献
38.
To date, luminescent materials have been preferably used for non-contact optical thermometers. In this manner, novel red-emitting Ba2Y0.8Eu0.2NbO6:Mn4+ (BYEN:Mn4+) phosphors were designed for multi-type non-contact luminescent thermometers based on the dual-emission states and temperature-dependent lifetime (TDL) models. In the temperature range of 303–483 K, the sensing sensitivities based on the dual-emission states of (5D0→7F2, 2Eg→4A2g) and (5D0→7F1, 2Eg→4A2g) were estimated. Especially, the maximum absolute sensing sensitivity (Sa) was found to be about 0.1558 K-1 for the BYEN:0.007Mn4+ phosphor based on the 5D0→7F1 and 2Eg→4A2g positions. This phosphor also exhibited good relative sensing sensitivity (Sr) (0.0186 K-1) based on the 5D0→7F2 and 2Eg→4A2g states. Besides, the relative sensing sensitivities (SR) at 5D0→7F1 and 2Eg→4A2g transitions were estimated to be 0.0034 and 0.0194 K-1, respectively with the help of the TDL technique. In the light of these results, novel red-emitting Ba2Y0.8Eu0.2NbO6:Mn4+ phosphors are expected to be a potentially attractive candidate for applications in multi-type luminescent thermometers. Finally, a novel unique polydimethylsiloxane film exhibiting tricolor-luminescent emissions was introduced and further suggested for high-security anti-counterfeiting. 相似文献
39.
Nicola Y. Edwards David M. Schnable Ioana R. Gearba-Dolocan Jenna L. Strubhar 《Molecules (Basel, Switzerland)》2021,26(1)
Lanthanide complexes have been developed and are reported herein. These complexes were derived from a terpyridine-functionalized calix[4]arene ligand, chelated with Tb3+ and Eu3+. Synthesis of these complexes was achieved in two steps from a calix[4]arene derivative: (1) amide coupling of a calix[4]arene bearing carboxylic acid functionalities and (2) metallation with a lanthanide triflate salt. The ligand and its complexes were characterized by NMR (1H and 13C), fluorescence and UV-vis spectroscopy as well as MS. The photophysical properties of these complexes were studied; high molar absorptivity values, modest quantum yields and luminescence lifetimes on the ms timescale were obtained. Anion binding results in a change in the photophysical properties of the complexes. The anion sensing ability of the Tb(III) complex was evaluated via visual detection, UV-vis and fluorescence studies. The sensor was found to be responsive towards a variety of anions, and large binding constants were obtained for the coordination of anions to the sensor. 相似文献
40.
The difference in time-resolved fluorescence spectrum between the cortical sarcoma and the adjacent normal tissue was studied
in both experimental and theoretical ways. The Clinical data were obtained in vivo using a time-resolved fluorescence spectrometer employing a single fiber-optic probe for excitation and detection. Tissue
was modeled as s-180 sarcoma tumor surrounded with normal muscle and was mediated by the Palladium-porphyrin photosensitizer
(Pd-TCPP). The emitted fluorescence was considered as arising from the tumor tissue or the normal muscle, due to the presence
of the photosensitizer. A computational code which could simulating time-resolved fluorescence emission was presented and
applied to comparing fluorescence decay of photosensitizer in different stages of tumor growth. In this code the different
stages of the tumor was modeled through changing the time τ, the delay of the fluorescence photon emission and z
max, the thickness of the tumor. It was found in the in vivo experiment that the fluorescence from tumor tissue decayed more quickly than from the adjacent normal muscle. For the ten
rats in the first experiment day, the mean decay constant of tumor T
s and normal tissue T
n were 554 and 526 μs, respectively. And T
s increased with the tumor growth, from 554 μs in the first day to 634 μs in the eighth day while T
s kept steady. It was believed that the more adequate oxygen supplied by the normal tissue can more effectively quench the
fluorescence and in the normal tissue the photosensitizer lifetime is smaller. As a result the simulated time-resolved fluorescence
spectrum of normal tissue showed more quickly decay. And the thickness of the tumor can also delay the fluorescence decay.
Both the experimental and simulated results indicated that the germination of the tumor would increase the decay constant
of the time-resolved fluorescence spectrum. So decay constant of the tumor tissue spectrum should be larger than that of adjacent
normal tissue for the reason of hypoxia and overgrouth. This fact could be of use in the tumor diagnoses. 相似文献