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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

Sensitized ligand narrow-band phosphorescence for high-efficiency solution-processed OLEDs

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Science China Chemistry 2022年第8期65卷 1559-1568页

作者： Qian Wang Jin-Yun Wang Hao Zeng Li-Yi Zhang Zhong-Ning Chen State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China University of Chinese Academy of Sciences Beijing 100039China

Narrow-band emission is crucial for high color purity in panel display.Nevertheless,attaining narrow-band emission is highly challenging because either thermally activated delayed fluorescence or phosphorescence in organic and metal-organic compounds originates primarily from multiple charge transfer transitions featured with broad bandwidths.In this work,a general tactic for achieving highly efficient narrow-band emission is proposed by the sensitization of ligand-centered phosphorescence through substantial intermetallic interaction.Relative to weak phosphorescence in mononuclear Pt(Ⅱ)precursors,highly efficient ligand-centered phosphorescence is dramatically activated in Pt(Ⅱ)-Au(Ⅰ)heteronuclear complexes with quantum yield as high as 81%in solutions and 97%in doping films.High-efficiency solution-processed organic light-emitting diodes(OLEDs)with narrow-band emission are successfully attained with external quantum efficiency(EQE)of 21.6%and a full width at half maxima(FWHM)of 36 nm for yellow electroluminescence and EQE of 20.8%and FWHM of 32 nm for green electroluminescence.

关键词： electroluminescence narrow-band emission organic light-emitting diode phosphorescence solution process

Nanostructured hafnium-doped strontium oxide film for homeotropic/homogeneous convertible liquid crystal alignment depending on the curing temperature

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International Journal of Smart and Nano Materials 2022年第4期13卷 597-611页

作者： Dong Hyun Kim Dong Wook Lee Jin Young Oh Jonghoon Won Hae-Chang Jeong Dae-Shik Seo IT Nano Electronic Device Laboratory Department of Electrical and Electronic EngineeringYonsei UniversitySeoulRepublic of Korea Department of Smart Manufacturing Engineering Changwon National UniversityChangwonGyeongnamRepublic of Korea Department of Electrical Electronic and Control Engineering Changwon National UniversityChangwonGyeongnamRepublic of Korea

A hafnium strontium oxide(HfSrO)liquid crystal(LC)alignment film was efficiently created through brush coating,and its ability to change the LC alignment direction was confirmed.A brush was applied to HfSrO sol coated on an indium-tin oxide substrate,after which the coating was solidified at var-ious curing temperatures.It was confirmed that a directional micro/nanostructure was formed above 280°C due to the shear stresses caused by the movement of the brush hairs.Surface chemical changes were analyzed by using X-ray photoelectron spectroscopy and contact angle measurements.As the curing temperature increased,the prevalence of oxygen bonds increased and the contact angle decreased,thereby increasing the surface energy.The anisotropic boundary of the micro-grooves and the van der Waals forces due to an increase in surface energy changed the alignment direction of LC mole-cules from vertical to horizontal,as verified through polarized optical microscopy and pretilt angle measurements.Thus,the efficiency of the brush-coating method,which dramatically simplifies the LC alignment film process,was confirmed.The homeotropic/homogeneous LC alignment property of the HfSrO film produced through brush coating depending on the curing temperature provides an innovative approach for LC alignment.

关键词： Brush coating nanostructure solution process liquid crystal alignment

New electron-donating segment to develop thermally activated delayed fluorescence emitters for efficient solution-processed non-doped organic light-emitting diodes

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Chinese Chemical Letters 2022年第2期33卷 1110-1115页

作者： Ming Zhang Gaole Dai Caijun Zheng Kai Wang Yizhong Shi Xiaochun Fan Hui Lin Silu Tao Xiaohong Zhang School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China(UESTC)Chengdu 610054China Institute of Functional Nano&Soft Materials(FUNSOM) Soochow UniversitySuzhou 215123China

Thermally activated delayed fluorescent(TADF) materials capable of efficient solution-processed nondoped organic light-emitting diodes(OLEDs) are of important and practical significance for further development of OLEDs. In this work, a new electron-donating segment, 2,7-di(9 H-carbazol-9-yl)-9,9-dimethyl-9,10-dihydroacridine(2 Cz-DMAC), was designed to develop solution-processable non-doped TADF emitters. 2 Cz-DMAC can not only simultaneously increase the solubility of compounds and suppress harmful aggregation-caused quenching, but also efficiently broaden the delocalization of the highest occupied molecular orbital and promote the reverse intersystem crossing process. Three new TADF emitters, 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)dibenzo[b,d]thiophene 5,5-dioxide(2 Cz-DMAC-BTB), 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)-9 H-thioxanthen-9-one(2 Cz-DMAC-TXO), 2-(2,7-di(9 H-carbazol-9-yl)-9,9-dimethylacridin-10(9 H)-yl)thianthrene 5,5,10,10-tetraoxide(2 Cz-DMAC-TTR), were developed by using 2 Cz-DMAC segment as the electron-donor. As anticipated, the solution-processed non-doped OLEDs employing 2 Cz-DMAC-BTB, 2 Cz-DMAC-TXO and 2 CzDMAC-TTR as the emitters respectively exhibited green, orange and red emissions with maximum external quantum efficiencies of 14.0%, 6.6% and 2.9%. These results successfully demonstrate the feasibility and convenience of developing efficient solution-processable non-doped TADF emitters based on 2 CzDMAC segment.

关键词： Electron-donating segment Thermally activated delayed fluorescence solution process Non-doped emitter Organic light-emitting diode

Highly sensitive ozone and hydrogen sensors based on perovskite microcrystals directly grown on electrodes

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Journal of Materiomics 2022年第2期8卷 446-453页

作者： Aikaterini Argyrou Konstantinos Brintakis Athanasia Kostopoulou Emmanouil Gagaoudakis Ioanna Demeridou Vassilios Binas George Kiriakidis Emmanuel Stratakis Foundation for Research and Technology Hellas(FORTH) Institute of Electronic Structure&Laser(IESL)P.O.Box 1385Heraklion 70013CreteGreece University of Crete Department of Chemistry71003 HeraklionCreteGreece University of Crete Department of Physics71003 HeraklionCreteGreece Crete Center for Quantum Complexity and Nanotechnology Department of PhysicsUniversity of Crete71003 HeraklionGreece

Highly-sensitive and stable ozone and hydrogen sensing elements were fabricated based on well-crystalline rounded cube-shaped CsPbBr 3 microcrystals,synthesized by a facile solution process per-formed under ambient conditions.It is shown that such elements demonstrate enhanced room tem-perature gas sensing ability compared to the previously reported metal halide and oxide-based ones.Electrical measurements performed on these sensing components revealed high sensitivity to ultra-low ozone and hydrogen concentrations,namely 4 ppb and 1 ppm respectively,as well as a remarkable repeatability,even after a few months of storage in ambient conditions.Both ozone and hydrogen sensors were self-activated,as they did not require the use of UV or heating external stimuli to operate,and exhibited fast detection and short restoration times.All such attractive properties along with the simple fabrication process could provide an easy,efficient and low-cost technology for the realization of future gas sensing devices.

关键词： All-inorganic perovskite crystals solution process Ozone sensing Hydrogen sensing High sensitivity Room-temperature sensor Perovskite sensors

Thermally activated delayed fuorescent small molecule sensitized fuorescent polymers with reduced concentration‑quenching for efcient electroluminescence

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Frontiers of Optoelectronics 2023年第1期16卷 41-48页

作者： Qin Xue Mingfang Huo Guohua Xie Department of Physical Science and Technology Central China Normal UniversityWuhan 430079China Sauvage Center for Molecular Sciences Hubei Key Lab on Organic and Polymeric Optoelectronic MaterialsDepartment of ChemistryWuhan UniversityWuhan 430072China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Thermally activated delayed fuorescence(TADF)small molecule bis-[3-(9,9-dimethyl-9,10-dihydroacridine)-phenyl]-sulfone(m-ACSO2)was used as a universal host to sensitize three conventional fuorescent polymers for maximizing the electroluminescent performance.The excitons were utilized via inter-molecular energy transfer and the non-radiative decays were successfully refrained in the condensed states.Therefore,the signifcant enhancement of the electroluminescent efciencies was demonstrated.For instance,after doping poly(9,9-dioctylfuorene-co-benzothiadiazole)(F8BT)into m-ACSO2,the external quantum efciency(EQE)was improved by a factor of 17.0 in the solution-processed organic light-emitting device(OLED),as compared with the device with neat F8BT.In terms of the other well-known fuorescent polymers,i.e.,poly(para-phenylene vinylene)copolymer(Super Yellow,SY)and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene](MEH-PPV),their EQEs in the devices were respectively enhanced by 70%and 270%,compared with the reference devices based on the conventional host 1,3-di(9H-carbazol-9-yl)benzene(mCP).Besides the improved charge balance in the bipolar TADF host,these were partially ascribed to reduced fuorescence quenching in the mixed flms.

关键词： Thermally activated delayed fuorescence(TADF) Organic light-emitting device(OLED) Sensitization Energy transfer solution process

Sky-blue perovskite light-emitting diodes based on quasi-two-dimensional layered perovskites

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Chinese Chemical Letters 2017年第1期28卷 29-31页

作者： Lu Cheng Yu Cao Rui Ge Ying-Qiang Wei Na-Na Wang Jian-Pu Wang Wei Huang Key Laboratory of Flexible Electronics & Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing Tech University Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials Jiangsu National Synergetic Innovation Center for Advanced Materials Nanjing University of Posts & Telecommunications

A mixed organic（4-phenylbutylamine, 4-PBA） and inorganic（cesium, Cs） cations are used to deposit quasi-two-dimensional layered perovskites. This layered perovskites exhibit good film coverage as twodimensional perovskites and high emission performance close to three-dimensional organic–inorganic hybrid perovskites. Light-emitting diodes（LEDs） are fabricated by using solution process based on the quasi-two-dimensional layered perovskites. The perovskite LEDs exhibit a sky-blue emission with electroluminescence peak at 491 nm and a low turn on voltage at 2.9 V. The maximum external quantum efficiency reaches 0.015% at brightness of 186 cd/m^2.

关键词： Perovskite light-emitting diodes Quasi-2D Sky-blue emission Morphology solution process

Through-space charge transfer polymers for solution-processed organic light-emitting diodes

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聚集体(英文) 2020年第1期1卷 45-56页

作者： Shiyang Shao Lixiang Wang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunP.R.China

Through-space charge transfer(TSCT)polymers are an attractive class of luminescent polymers with spatial donor/acceptor architecture and thermally activated delayed fluorescence effect,different from conventional luminescent polymers with conjugated donor-acceptor structure and through-bond charge transfer emission.Their emission comes from the intramolecular charge transfer by through-space pathway because the donor and acceptor segments are spatially proximate to each other in each repeating unit but are physically separated by nonconjugated polymer backbone.In this review,recent advances in TSCT polymers with linear,bottlebrush,and dendritic architectures are presented,with the focus on their molecular design,photophysical behavior,and device performance.We hope that this review shall provide a useful insight of new luminescent polymers with TSCT effect for use in solution-processed organic light-emitting diodes.

关键词： luminescent polymer organic light-emitting diodes(OLEDs) solution process through-space charge transfer

Hydrazine processed Cu2SnS3 thin film and their application for photovoltaic devices

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Frontiers of Optoelectronics 2014年第1期7卷 37-45页

作者： Jun HAN Ying ZHOU Yang Tian Ziheng HUANG Xiaohua WANG Jie ZHONG Zhe XIA Bo YANG Haisheng SONG Jiang TANG School of Science Changchun University of Science and Technology Changchun 130022 China Wuhan National Laboratory for Optoelectronics (WNLO) Huazhong University of Science and Technology Wuhan 430074 China Department of Environmental Science College of Environmental Sciences Minzu University of China Beijing 100081 China School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China

Copper tin sulfide （Cu2SnS3） was a potential earth abundant absorber material for photovoltaic device application. In this contribution, triclinic Cu2SnS3 film with phase pure composition and large grain size was fabricated from a hydrazine solution process using Cu, Sn and S as the precursors. Absorption measurement revealed this Cu2SnS3 film had a direct optical band gap of 0.88 eV, and Hall effect measurement indicated the film was p-type with hole mobility of 0.86 cmE/Vs. Finally Mo/Cu2SnS3/ CdS/ZnO/AZO/Au was produced and the best device efficiency achieved was 0.78%. Also, this device showed improved device performance during ambient storage. This study laid some foundation for the further improve- ment of Cu2SnS3 solar cell.

关键词： copper tin sulfide （Cu2SnN3） solar cell,hydrazine solution process triclinic