High‐efficiency all‐fluorescent white organic light‐emitting diodes (WOLEDs) are demonstrated by employing a blue thermally activated delayed fluorescent as the host or assistant dopant and a ...conventional orange emitter. The resulting warm WOLEDs, using thermally activated delayed fluorescence as the host, show a record external quantum efficiency of 14.0% and a power efficiency of 48.0 lm W−1, together with an extremely low efficiency roll‐off.
This paper used the panel data of various regions in China from 2007 to 2018 and constructs a green economic efficiency measurement index system. Following this, the super-efficient DEA model has ...been employed to measure the efficiency of China's green economy. Then, the Tobit model is used to verify the environmental regulation influence on efficiency of China's regional green economy extent and direction. The results show that: (1) in 2007–2018, the green economy efficiency level of China's eastern, central and western regions is on the rise, accompanied by more obvious spatial differences. The green economy efficiency basically shows the spatial differentiation characteristics of the highest in the eastern region and the lowest in the western region. (2) From the national perspective, environmental regulation influence on efficiency of green economy presents a “U” shaped curve that promotes and then suppresses. At the eastern and national levels, environmental regulation has the same characteristics for green economy efficiency, and both exhibit U-shaped curve characteristics. Whereas, in the central and western regions shows negative correlation. (3) From the perspective of control variables, there are significant differences in variables at the national and regional levels. Finally, the study concludes with some policy suggestion for future green development and the formulation of environmental regulations in China.
•Measuring the Efficiency of China's Green Economy by Using Super Efficiency DEA Model.•Environmental regulations impact on green economy efficiency by the Tobit model.•Environmental regulation impact on green economy efficiency presents “U” process.•Environmental regulation impact on green economy efficiency difference in China.
Designing a donor-acceptor (D-A) molecule with a hybridized local and charge transfer (HLCT) excited state is a very effective strategy for producing an organic light-emitting diode (OLED) with a ...high exciton utilization efficiency and external quantum efficiency. Herein, a novel twisting D-π-A fluorescent molecule (triphenylamine-anthracene-phenanthroimidazole; TPAAnPI) is designed and synthesized. The excited state properties of the TPAAnPI investigated through photophysical experiments and density functional theory (DFT) analysis reveal that its fluorescence is due to the HLCT excited state. The optimized non-doped blue OLED using TPAAnPI as a light-emitting layer exhibits a novel blue emission with an electroluminescence (EL) peak at 470 nm, corresponding to the Commission International de L'Eclairage (CIE) coordinates of (0.15, 0.22). A fabricated device termed Device II exhibits a maximum current efficiency of 18.09 cd A
−1
, power efficiency of 12.35 lm W
−1
, luminescence of 29 900 cd cm
−2
, and external quantum efficiency (EQE) of 11.47%, corresponding to a high exciton utilization efficiency of 91%. Its EQE remains as high as 9.70% at a luminescence of 1000 cd m
−2
with a low efficiency roll-off of 15%. These results are among the best for HLCT blue-emitting materials involved in non-doped blue fluorescent OLEDs. The performance of Device II highlights a great industrial application potential for the TPAAnPI molecule.
A new pure fluorescent blue HLCT-emitter was designed and synthesized. Highly efficient non-doped blue OLEDs with low efficiency roll-off were achieved.
A new resonant converter having low voltage stress and nearly constant efficiency against line variation for high- and wide-input-voltage applications is presented in this paper. It is similar to a ...three-level zero-voltage-switching pulsewidth modulation converter (TL ZVS PWMC) with two flying capacitors. In the proposed converter, however, two flying capacitors are used as the resonant capacitors, and the output voltage regulation is achieved by frequency modulation. The main advantages of the proposed converter are that, since the sum of the voltages of two resonant capacitors is constant and is equal to half of the input voltage, the voltage across each switch clamps to half of the input voltage and keeps the balance. Moreover, all main switches and rectifier diodes are softly switched under full-line and full-load conditions, and high efficiency can be constantly achieved over a wide input voltage range. These advantages solve the drawbacks on TL ZVS PWMCs. The features, operation principles, and relevant analysis results over a wide input voltage range of the proposed converter are presented in this paper. The validity of this study is confirmed by the experimental results of a prototype converter with 400-600-V input, 48-V/10-A output, and 200-kHz resonant frequency. The experimental results show that the maximum efficiency of the proposed converter is 95.08% under a full-load and a 600-V input and slightly varies across the 400-600-V input voltage range.
Punnoose A, McConnell LA, Liu W, Mutter AC, Koder RL (2012) Fundamental Limits on Wavelength, Efficiency and Yield of the Charge Separation Triad. PLoS ONE 7(6): e36065. ...doi:10.1371/journal.pone.0036065 Citation: Punnoose A, McConnell LA, Liu W, Mutter AC, Koder RL (2012) Correction: Fundamental Limits on Wavelength, Efficiency and Yield of the Charge Separation Triad.
Electroluminescence efficiencies of metal halide perovskite nanocrystals (PNCs) are limited by a lack of material strategies that can both suppress the formation of defects and enhance the charge ...carrier confinement. Here we report a one-dopant alloying strategy that generates smaller, monodisperse colloidal particles (confining electrons and holes, and boosting radiative recombination) with fewer surface defects (reducing non-radiative recombination). Doping of guanidinium into formamidinium lead bromide PNCs yields limited bulk solubility while creating an entropy-stabilized phase in the PNCs and leading to smaller PNCs with more carrier confinement. The extra guanidinium segregates to the surface and stabilizes the undercoordinated sites. Furthermore, a surface-stabilizing 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene was applied as a bromide vacancy healing agent. The result is highly efficient PNC-based light-emitting diodes that have current efficiency of 108 cd A−1 (external quantum efficiency of 23.4%), which rises to 205 cd A−1 (external quantum efficiency of 45.5%) with a hemispherical lens.Guanidinium doping is shown to enhance the operation of perovskite nanocrystal light-emitting diodes.
The amalgamation of thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) properties, termed AIE-TADF, is a promising strategy to design novel robust luminescent ...materials. Herein, we transform 2,3,4,5,6-penta(9
H
-carbazol-9-yl)benzonitrile (5CzBN) from an ACQ molecule into an AIEgen by simply decorating the 5CzBN core with alkyl chain-linked spirobifluorene dendrons. By increasing the number of flexible dendrons, these materials can not only show obvious AIE-TADF characteristics and uniform film morphology, but can also exhibit better resistance to isopropyl alcohol, which are beneficial to fully solution-processed OLEDs. Notably, 5CzBN-PSP shows great device efficiency with an external quantum efficiency (EQE), current efficiency and power efficiency of 20.1%, 58.7 cd A
−1
and 46.2 lm W
−1
, respectively and achieved record-breaking efficiency in solution-processed nondoped OLEDs based on AIE emitters. This work demonstrates a general approach to explore new efficient emitters by the marriage of AIE and TADF which could potentially improve their performance in various areas.
Construction of core-dendron TADF emitters systematically: changing the behaviour of chromophores from aggregation-caused quenching to aggregation induced emission to develop high-performance fully solution-processed nondoped OLEDs.
White organic light‐emitting diodes (WOLEDs) with high efficiencies and tunable colors attracts considerable interest from the industry and academia. Thermally activated delayed‐fluorescence (TADF) ...emitters can revolutionize such WOLED devices; however, they still suffer from poor performances. In this study, an advanced double‐emissive‐layer device architecture capable of hole‐trapping TADF‐sensitized emissions is proposed to not only achieve a recombination zone shift for the tunable colors but also accelerate exciton emission dynamics for high efficiency and alleviated roll‐off. The proof‐of‐concept WOLEDs exhibit significant shifts in their Commission Internationale de l'Eclairage (CIE) coordinates and correlated color temperatures from (0.40, 0.47) and 4088 K at 100 cd m−2 to (0.27, 0.33) and 9269 K at 5000 cd m−2. Additionally, the maximum external quantum efficiency (EQE) reaches 30.7% and remains >25% over a wide luminance range of 500–5000 cd m−2, along with an extended LT80 of over 20 000 h at an initial luminance of 100 cd m−2. This is the first time that all‐fluorescent WOLEDs have been used to realize an EQE exceeding 30%, thereby establishing a new benchmark in this field.
Color‐tunable white organic light‐emitting diodes with hole‐trapping thermally activated delayed‐fluorescence‐sensitized emissions realize significant Commission Internationale de l'Eclairage coordinates and correlated color temperature shifts from (0.40, 0.47) and 4088 K at 100 cd m−2 to (0.27, 0.33) and 9269 K at 5000 cd m−2, with a reported maximum external quantum efficiency of 30.7% and long lifetime of over 20 000 h at 80% of the initial luminance.
The paper discusses the issue of utilization of the major online public evaluation platforms as Facebook and Google, more specifically describes the methods and ways of their utilization in the field ...of healthcare provider with aim to increase competitiveness on subjects operating on this specific sector. The issue of increasing the efficiency and quality of health services has long been proclaimed. There is no coherent plan for measuring the quality and efficiency of healthcare facilities in general. The increasing importance and demands for efficiency and quality is leading to an increase in importance of accurate and specific marketing concepts, desirable also in the process of specific health programs. By thorough and complex analysis of online presence of selected health care providers, represented by the Slovak Teaching Hospitals, relationships between factors were examined in order to identify and describe facts affecting online presence of those entities in the hyper competitive market environment of the Internet. The findings identified by the analysis of online environment were compared between selected platforms. The results of analysis thus providing a comprehensive view on the issue of utilization of online evaluation platforms to increase competitiveness.
The strategy is a macro and strategic plan, and will only be implemented when it is defined in the form of various projects. In order to exploit the benefits of lean six sigma projects, these ...projects should be in line with the strategic goals of the organization. Organizations should select projects which are compatible with the organization overall goals and fulfill the strategic requirements of the organization. The purpose of this study is to identify the strategic process among the bank facility processes to use it in lean six sigma methodology in order to improve process performance and efficiency using a combination of cross-efficiency and extended balanced scorecard methods. In the first step, the criteria for selecting the strategic process were identified using the six measures of the balanced scorecard method. In the second step, after collecting information using the cross-efficiency model based on satisfaction level, the bank facility processes are ranked based on the efficiency score. The results show that the ranking of the processes under consideration is carried out without any interference, and one of the processes (process 3) is considered as the strategic process to use in the six sigma methodology.
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