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narrowband blue emitter based on fused nitrogen/carbonyl combination with external quantum efficiency approaching 30%

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Science China Chemistry 2024年第1期67卷 351-359页

作者： Long Chen Jia-Heng Cai You-Jun Yu Yang-Kun Qu Sheng-Yi Yang Sheng-Nan Zou Rui-Hong Liu Dong-Ying Zhou Liang-Sheng Liao Zuo-Quan Jiang Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesSoochow UniversitySuzhou 215123China Macao Institute of Materials Science and Engineering Macao University of Science and TechnologyMacao 999078China

Multi-resonance thermally activated delayed fluorescence(MR-TADF)emitters can enable narrowband emission with high color purity and electroluminescence efficiency.Nitrogen/carbonyl(N/C=O)system is receiving increasing attention while the nitrogen/boron(N/B)system has been widely studied.Donor decoration is an effective approach for N/B type MR-TADF system but always leads to broadening and red-shifting of the emission band in N/C=O MR-TADF system.We attribute these unfavorable phenomena to the formation of intramolecular charge transfer between the MR-core and peripheral donors.To address this issue,we have developed a new strategy by decorating DMQAO(a fused N/C=O MR-core)with a triazine acceptor and a neutral terphenyl group to construct MTDMQAO and MBDMQAO,respectively.The introduction of the triazine acceptor not only realizes efficient narrowband emission in MTDMQAO,but also accelerates the reverse intersystem crossing process through enhanced spin-orbital coupling.As a result,MTDMQAO exhibits a significantly higher external quantum efficiency of 29.4%compared to the referent emitters,validating the rationality of our derivation strategy.This study highlights the potential of the N/C=O system for MR-TADF emitters and provides important insights for understanding the difference between N/B and N/C=O systems.

关键词： carbonyl group narrowband acceptor decoration thermally activated delayed fluorescence OLEDs

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High-definition colorful perovskite narrowband photodetector array enabled by laser-direct-writing

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Nano Research 2022年第6期15卷 5476-5482页

作者： Xiaobao Xu Yuhang Dong Yuanzhou Zhang Zeyao Han Jiaxin Liu Dejian Yu Yi Wei Yousheng Zou Bo Huang Jun Chen Haibo Zeng Key Laboratory of Advanced Display Materials and Devices Ministry of Industry and Information TechnologyInstitute of Optoelectronics&NanomaterialsCollege of Material Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China

narrowband photodetectors as specific spectral sensing pixels have drawn intense attention in multispectral detection due to their distinct characteristic of filter-free spectrum discrimination,in which the emerging halide lead perovskites witness a booming development in their performance and wavelength-selectivity from blue to near-infrared light.However,the challenge in integrating perovskite narrowband photodetectors on one chip imposes an impediment on practical application.In this work,the combination of laser-direct-writing and ion exchange is proposed as an efficient way to fabricate high-definition colorful sensing array with perovskite narrowband photodetector unit as pixel.Under laser irradiation,the photolysis of halocarbon solvent(CHCl_(3),CH_(3)CH_(2)I,etc)releases the halide ions,which brings the ion exchange and gives rise to slow-varying bandgap in single perovskite photoactive film.This ion exchange can be controlled via laser irradiation time and focus point,thus enabling precisely engineerable bandgap.By optimizing the process,it is successfully applied to develop patterned perovskite narrow blue and green photodetectors array with a high-definition of~53 ppi.We believe this result will make a great step forward to integrate multifunctional perovskite devices on one chip,which will pave the way for perovskite optoelectronic device to the commercial application.

关键词： photodetector narrowband imaging array laser-direct-writing perovskite

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Boron-, Sulfur- and Nitrogen-Doped Tridecacyclic Aromatic Emitters with Multiple Resonance Effect for narrowband Red Emission

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Chinese Journal of Chemistry 2022年第22期40卷 2671-2677页

作者： Yinuo Wang Kaiyuan Zhang Fan Chen xingdong Wang Qingqing Yang Shumeng Wang Shiyang Shao Lixiang Wang state Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefeiAnhui 230026China State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikouHainan570228China

Two novel boron(B),sulfur(S),nitrogen(N)-doped polycyclic aromatic hydrocarbon multiple resonance emitters(DBNS and DBNS-tBu)are designed and synthesized for narrowband red emission by embedding two pairs of S and N atoms and two B atoms in para-positions of central benzene rings within a tridecacyclic aromatic skeleton to form donor-π-donor(D-π-D)and acceptor-π-acceptor(A-π-A)structures,which not only exhibit emission maximum at 641 nm with small full width at half maximum of 39 nm,but also combine high photoluminescent quantum efficiency(85%)and rapid reverse intersystem crossing(kRISC=2.2×10^(5) s^(−1)).

关键词： Multipleresonance Polycycles Donor-acceptor systems Sulfur narrowband

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Carbazole-based Multiple Resonance Dendrimers with narrowband Blue Emission for Solution-Processed OLEDs

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Chinese Journal of Polymer Science 2023年第5期41卷 802-810,I0011页

作者： Jia-Peng Liu Liang Chen Lei Zhao Cui-Yan Tong Shu-Meng Wang Shi-Yang Shao Li-Xiang Wang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Institute of Chemistry Northeast Normal UniversityChangchun 130024China State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikou 570228China

Three carbazole-based multiple resonance dendrimers namely D1-BNN,D2-BNN and D3-BNN,are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs)by introducing the first-,second-,and third-generation carbazole dendrons in periphery of boron,nitrogen-doped polycyclic aromatic hydrocarbon skeleton.Different from D1-BNN containing first-generation carbazole dendron showing moderate photoluminescent quantum efficiency(PLQY)of 68%in solid state and broadened emission bands with full-width at half maximum(FWHM)increasing from 26 nm to 34 nm upon doping concentration growing from 10 wt%to 40 wt%,D3-BNN with the third-generation carbazole dendron exhibits high PLQY of 92%and weak dependence of photoluminescent spectra on doping concentration,which can remain narrowband emissions with unchanged FWHM of 24 nm at same doping concentration range.Solution-processed OLEDs employing D3-BNN as emitter reveal blue electroluminescence at 477 nm with FWHM of 24 nm,and maximum external quantum efficiency(EQE)of 17.3%which is kept at 14.4%at doping concentration of 40 wt%,much superior than the D1-BNN devices showing maximum EQE of 13.0%that drops to 3.7%at 40 wt%doping concentration.

关键词： Multiple resonance Dendrimer narrowband Blue emission Solution process

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Non-conjugated Polynorbornene Hosts with High Triplet Energy Levels for Solution-processed narrowband Blue OLEDs

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Chemical Research in Chinese Universities 2023年第5期39卷 763-771页

作者： LI Qiang CHEN Liang WANG Xingdong WANG Shumeng SHAO Shiyang WANG Lixiang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026P.R.China State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and EngineeringHainan UniversityHaikou 570228P.R.China

Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs).It is found that the non-conjugated polynorbornenes can keep high triplet energy(ET)levels in range of 3.12-3.20 eV by interrupting the conjugation of repeating units,making them capable as host materials for blue emitters.Meanwhile,by increasing the electron-donating capability of side chain arylamine from carbazole to acridan and dendritic teracridan,the highest occupied molecular orbital(HOMO)levels for the polymer hosts are elevated from-5.50 eV to-5.11 eV,beneficial for reducing the hole injection barrier from anode to emissive layer.As a result,solution-processed OLEDs employing polynorbornenes with dendritic teracridan side chain(PNB-TAc)as host and boron,selenium,nitrogen-containing multiple resonance thermally activated delayed fluorescence emitter as dopant reveal efficient narrowband blue electroluminescence with emission peak at 474 nm,full-width at half maximum of 30 nm,together with maximum external quantum efficiency of 20.2%,representing the state-of-the-art device efficiency for solution-processed OLEDs with narrowband blue emission.

关键词： Polymer host Polynorbornene Organic light-emitting diode Solution-processed narrowband Blue emission

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narrowband imaging method for spatial precession cone-shaped targets

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Science China(Technological Sciences) 2010年第4期53卷 942-949页

作者： DING XiaoFeng1,FAN MeiMei1,WEI XiZhang1,LI Xiang1 & Xiao HuaiTie2 1 Institute of Space Electronics Information Technology,National University of Defense Technology,Changsha 410073,China 2 School of Electronic Science and Engineering,National University of Defense Technology,Changsha 410073,China Institute of Space Electronics Information Technology National University of Defense Technology Changsha China School of Electronic Science and Engineering National University of Defense Technology Changsha China

The imaging method of the mid-course missile is the key technique of the missile defense system.Because of the special precession character of the ballistic missile warhead,the inverse synthetic aperture radar method cannot realize phase compensation with the constant phase offset function,which leads to blurring of the image.In this paper,we propose a new narrowband radar imaging method for the precession cone-shaped targets.The method acquires the Doppler modulation of the precession target's scattering centers with high resolution time-frequency analysis method and extracts the Doppler parameter from the result of the time-frequency analysis with the general Radon transform,then reconstructs the scattering centers positions in the parameter domain.The experiment results with the anechoic chamber data of the representative cone-shaped object showed the effectiveness of the method.

关键词： narrowband radar imaging time-frequency analysis general Radon transform

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Observation and study on the whole process of cloud-to-ground lightning using narrowband radio interferometer

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Science China Earth Sciences 2008年第5期51卷 694-708页

作者： ZHANG GuangShu ZHAO YuXiang QIE XiuShu ZHANG Tong WANG YanHui CHEN ChengPin Laboratory for Climate Environment and Disasters of Western China Cold and Arid Regions Environmental and Engineering Re-search InstituteChinese Academy of SciencesLanzhou 730000China Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Tianshui Normal College Tianshui 741001China

A narrowband radio interferometer has been developed and used to locate the entire sources of VHF radiations from a negative cloud-to-ground (CG) lightning discharge which contains 19 strokes. This system uses five antennas to form an array consisting of short- and long-baselines along two or- thogonal directions. The system error which comes from frequency conversion is reduced by phase detection through direct high frequency amplifying. An interactive graphic analysis procedure is used to remove the fringe ambiguities which exist inherently in interferometry and to determine the direction of lightning radiation sources in two dimensions (azimuth and elevation) as a function of time at a time resolution of microsecond orders. With the developed system, the whole progression process in time and space of a lightning flash can be reconstructed. In this paper, combining the synchronous data of electric filed change and VHF radiation, the whole processes of an example negative CG flash have been studied in detail. It is found that the preliminary breakdown event of the CG flash started from negative charge region and exhibited firstly a downward pregression and then an upward propagation. There were very intense and continuous radiations during stepped leaders which became much stronger when the first return stroke began. In contrast, there were less and only discrete radiations during dart leaders. Stepped leader and dart leader may transform to each other depending on the state of the ionization of the path. The progression speed of initial stepped leaders was about 105 ms?1, while that was about 4.1×106 and 6.0×106 ms?1 for dart leaders and dart-stepped leaders, respectively. M events produced hook-shaped field changes accompanied by active burst of radiations at their begin- nings. Followed these active radiation processes, M events appeared to contact finally into conducting main discharge channels. The mean progression speed of M events was about 7×107 ms?1, greater than that of the dart leaders and dart-step l

关键词： lightning narrowband interferometer dart leader K events M events the whole process of cloud-to-ground lightning

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Recent Progress on Organic Near-Infrared Photodetectors:Mechanism,Devices,and Applications

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Chinese Journal of Chemistry 2023年第8期41卷 958-978页

作者： Qingkai Wang Yajie Zhang Zhixiang Wei CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190 China

Comprehensive Summary Near infrared light organic photodetectors have attracted tremendous attention due to their tailorable response,ease of processing,compatibility with flexible substrate,room temperature operation and broad applications such as remote sensing,health monitoring,artificial vision,night vision,and so on.Recently,the great improvement obtained on the important figures of merit performances has made organic photodetectors catch up and even surpass those of inorganic photodetectors in some respects.In this review,after a brief illustration of the organic photodetectors'figures of merit performances,we summarize the research progress of panchromatic and narrowband near infrared light organic photodetectors from their working mechanism,strategies to achieve narrowband near infrared light organic photodetectors,to some practical applications.Finally,we discuss the development challenge of the near infrared light organic photodetectors.

关键词： Organic photodetectors Near-infrared Panchromatic narrowband Applications

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Esophageal early basaloid squamous carcinoma with unusual narrowband imaging magnified endoscopy findings

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World Journal of Gastroenterology 2014年第35期20卷 12673-12677页

作者： Yugo Kai Motohiko Kato Yoshito Hayashi Tomofumi Akasaka Shinichiro Shinzaki Tsutomu Nishida Masahiko Tsujii Eiichi Morii Tetsuo Takehara Department of Gastroenterology and Hepatology Osaka University Graduate School of Medicine Department of Diagnostic Pathology Osaka University Hospital

Basaloid squamous carcinoma(BSC)is a rare variant of esophageal cancer.There are very few reports of"early"BSC.Here we report a case of early BSC with unusual findings by narrowband imaging magnified endoscopy(NBI-ME).A 70-year-old man with a middle thoracic esophageal tumor was referred to our hospital.White-light endoscopy revealed a reddish depressed lesion 5 mm in diameter having a subepithelial tumor-like prominence with a gentle rising slope.NBI-ME revealed irregular loop-shaped microvessels coexistent with thick irregularly branched non-looped vessels.Iodine staining revealed a pale brown lesion.We performed endoscopic submucosal dissection for diagnostic treatment.Histologic examination showed the proliferation of basal cell-like hyperchromatic tumor cells in the lamina propria and with slight invasion into the submucosa at a depth of 320μm.The tumor cells formed solid nests and microcystic structures,containing an Alcian blue-positive mucoid matrix.The surface was covered with squamous epithelium without cellular atypia.Thin vessels were observed in the intra-epithelial papilla and thick vessels were observed around the solid nests beneath the epithelium.Based on these findings together,we diagnosed the lesion as BSC.In this case,the NBI-ME findings differed from those of typical squamous cell carcinoma in that both non-invasive cancer-like irregular loop-shaped microvessels coexisted with massively invasive cancerlike thick non-looped vessels.We speculate that the looped and non-looped vessels observed by NBI-ME histologically corresponded to thin vessels in the intraepithelial papilla and thick vessels around the tumor nests,respectively.These NBI-ME findings might be a feature of early esophageal BSC.

关键词： Basaloid squamous carcinoma narrowband imaging Eso

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narrowband Notch Filters with Composite Nanostructure Layers on a GaN-based Light Emitting Diode

Narrowband Notch Filters with Composite Nanostructure Layers...

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2012 International Conference on Nanotechnology Technology and Advanced Materials(ICNTAM 2012)

作者： Bing Cao Guiju Zhang Chinhua Wang Jianfeng Wang Ke Xu Institute of Modern Optical Technologies and Key Lab of Modern Optical Technologies of Jiangsu Province Soochow University Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences

In this paper, novel active narrowband notch filters with triple-layer composite nanostructures on a Ga N-based LED are obtained by mainly adjusting the grating period and duty cycle. The three layers consist of two dielectric thin layers and one metallic / dielectric grating layer. The grating layer composes of subwavelength period and thickness rectangular stripes, which lies between a transition layer and a protecting layer. Line-width and attenuation peak properties of the resonance filters are calculated and investigated by using a full vector implementation of Rigorous Coupled Wave Analysis(RCWA) algorithm. It is shown that the grating period can significantly change the filter peak wavelength, and the grating duty cycle heavily changes the filter line-width. The filter attenuation peak has a red shift with 23.3nm as the grating period increases 18 nm. The FWHM(Full Width at Half Maximum) of the filter reduces from 1.9nm to 0.28 nm as the duty cycle changes from 0.55 to 0.3, which compressed more than six times. Moreover, thickness of each composite nanostructure layer can also affect the narrowband width and peak wavelength of the filter. The results provide guidance in designing, optimizing and fabricating such an active narrowband filter with highly integrated photonic devices.

关键词： notch filters narrowband Gallium nitride nanostructure

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