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| 1 | Highly efficient pure white polymer light-emitting devices based on poly(N-vinylcarbazole) doped with blue and red phosphorescent dyes显示文摘Efficient white-polymer-light-emitting devices (WPLEDs) have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly(N-vinylcarbzole),and an electron-transporting auxiliary,1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl]-phenylene,codoped with two phosphorescent dyes:Iridium(III)bis (2-(4,6-difluorophenyl)-pyridinato-N,C2') picolinate (FIrpic) and home-made Ir-G2 for blue and red emission,respectively.With the structure of ITO/PEDOT:PSS 4083(40 nm)/emission layer(80 nm)/Ba(4 nm)/Al(120 nm),the device showed a maximal luminous efficiency (LE) of 13.5 cd A-1(corresponding to an external quantum efficiency (EQE) of 6.8%),and a peak power efficiency (PE) of 6.5 lm W-1 at 6.0 V.Meanwhile,the device exhibited pure white emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.34,0.35) at a current density of 12 mA cm-2,which is very close to the equi-energy white point with CIE coordinates of (0.33,0.33).The device performance can be further optimized when more balanced hole/electron injection is achieved by incorporating a lower conducting type anode buffer layer (PEDOT:PSS) and incorporating poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorenene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) as an electron injection layer at the cathode.The optimized device showed an LE of 24.6 cd A-1 (with an EQE of 14.1%),while the peak power efficiency reached 12.66 lm W-1.Moreover,the WPLEDs showed good electroluminescence (EL) stability over a wide range of operating current density and luminance. | HU SuJun ZOU JianHua ZHOU GuiJiang LI DongYun WU HongBin SU ShiJian WONG Wai-Yeung YANG Wei PENG JunBiao CAO Yong | 2011 | Science China Chemistry2011，54，4： | 4 |
| 2 | Microstructure and hardness investigation of 17-4PH stainless steel by laser quenching显示文摘 | CHEN ZHAOYUN ZHOU GUIJIANG CHEN ZHON- GHUA | 2012 | Material Science and Engineering A2012，，534： | 1 |
| 3 | Asymmetric Tris-Heteroleptic Cyclometalated Phosphorescent Iridium(III)Complexes:An Emerging Class of Metallophosphors显示文摘CONSPECTUS:The rapid developments of cutting-edge research on photofunctional organic semiconductor materials are greatly promoting the progress of science and technology.As one of the most important organic semiconductor materials,phosphorescent iridium(III)complexes are a promising class of organometallic emitters because of their rich emissive excited states together with excellent chemical stability,which have been widely used in various fields,such as organic electroluminescence,solar cells,photo-catalysis,biosensing,bioimaging,cancer therapy,etc.The exploration of highly efficient phosphorescent iridium(III)complexes showing various structural features is blooming quickly.In general,the traditional iridium(III)phosphors usually contain at least two identical cyclometalating bidentate ligands.These iridophosphors with two identical bidentate ligands are termed as the bis-heteroleptic complex Ir((L1)2L2),where L denotes the free ligand or the deprotonated form of the free ligand.Those with three identical ligands are called homoleptic complex Ir(L)3.Recently,the iridium(III)complexes Ir(L1L2L3)supported by three different(cyclometalating)ligands are emerging as a novel and interesting category of phosphors.This class of iridophosphors usually refers to tris-heteroleptic cyclometalated phosphorescent iridium(III)complexes,and they usually show the asymmetry in their molecular structures.Compared with the case for the traditional iridium(III)phosphors,the independent ligand control provides tris-heteroleptic iridium(III)phosphors with more flexible molecular design/synthesis and excited-state fine-tuning ability,thereby resulting in more rich and appealing excited states and potential multifunctional applications.In this Account,we will highlight our recent efforts on the asymmetric tris-heteroleptic cyclometalated iridium(III)phosphors including the molecular design strategies,chemical synthesis,excited-state tuning,and structure−property relationships as well as their applications,especially in organic electroluminescence.Specifically,the molecular design of tris-heteroleptic iridium(III)phosphors focuses on the independent ligand design including the following three aspects:(1)the substituent functionalization engineering(SFE);(2)the ligand skeleton engineering(LSE);(3)the double metalation engineering(DME).For SFE,we mainly introduce the substituent based on the main-group element into the ligand of iridophosphors and also investigate the influence of the substituent position on the emissive excited states of iridophosphors.For instance,the main-group elements show unique electronic effects,which could contribute to the manipulation of the photoelectric properties of complexes(e.g.,balanced charge transport ability,improved utilization of excitons,etc.).For LSE,different types of aromatic skeleton or various lengths ofπconjugation of the ligands are also examined for the effective tuning of their excited states.For DME,the type and spatial orientation of the bridging/franking ligand will be considered.At the same time,the related optoelectronic applications(e.g.,electroluminescence,optical power limiting,etc.)of this novel class of versatile iridophosphors are also discussed.Finally,we give some perspectives on this fascinating topic and also try to provide some potential research opportunities based on the current stage of asymmetric tris-heteroleptic cyclometalated phosphorescent iridium(III)complexes.It is believed that the emerging asymmetric tris-heteroleptic cyclometalated iridophosphors will open an important avenue for designing novel metallophosphor-based materials with tunable and appealing photophysical properties,thus offering new probabilities for potential multifunctional applications. | Peng Tao Xingqiang Lü Guijiang Zhou Wai-Yeung Wong | 2022 | Accounts of Materials Research2022，3，8： | 1 |
| 4 | Design and synthesis of low dipole moment chromophores:2,6-disubstitute cycloheptimidazoles显示文摘 | Guijiang Zhou Zhou Yang | 2003 | Synthetic Metals2003，137，3： | 1 |
| 5 | Recent progress and current challenges in phosphorescent white organic light-emitting diodes (WOLEDs)显示文摘 | Guijiang Zhou Wai-Yeung Wong Si Suo | 2011 | Journal of Photochemistry & Photobiology C: Photochemistry Reviews2011，，4： | 1 |
| 6 | Silafluorene moieties as promising building blocks for constructing wide-energy-gap host materials of blue phosphorescent organic light-emitting devices显示文摘In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis(5-methyl-5Hdibenzo[b,d]silol-5-yl)benzene(Me-DBSi B), for blue phosphorescent organic light-emitting devices(PHOLEDs). The MeDBSi B was constructed by linking 9-methyl-9-silafluorene units to the phenyl framework through the sp3-hybridized silica atom to maintain high singlet and triplet energy, as well as to enhance thermal and photo-stability. The calculated result shows that the phenyl core does not contribute to both the highest occupied molecular orbital and lowest unoccupied molecular orbital. Wide optical energy gap of 4.1 e V was achieved. When the Me-DBSi B was used as the host and iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C2′]picolate(Firpic) as the guest, a maximum current efficiency was 14.8 cd/A, lower than the counterpart of 1,3-bis(9-carbazolyl)benzene(28 cd/A). The unbalanced barrier for electron and hole injection to host layer may be responsible for low efficiency. Even so, our results show that silafluorene moieties are promising building blocks for constructing wide-energy-gap host materials. | Dongdong Wang Qingqing Liu Yue Yu Yong Wu Xinwen Zhang Hua Dong Lin Ma Guijiang Zhou Bo Jiao Zhaoxin Wu Runfeng Chen | 2015 | Science China Chemistry2015，58，6： | 0 |
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