Rapid crystallization-driven high-efficiency phase-pure deep-blue Ruddlesden–Popper perovskite light-emitting diodes

Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of deep-blue(<460 nm)PeLEDs still lag far behind their red and green counterparts.Herein,a rapid crystallization method based on hot-antisolvent bathing is proposed for realization of deep-blue PeLEDs.By promoting immediate removal of the precursor solvent from the wet perovskite films,development of the quasi-two-dimensional(2D)Ruddlesden–Popper perovskite(2D-RPP)crystals with n values>3 is hampered completely,so that phase-pure 2D-RPP films with bandgaps suitable for deep-blue PeLEDs can be obtained successfully.The uniquely developed rapid crystallization method also enables formation of randomly oriented 2D-RPP crystals,thereby improving the transfer and transport kinetics of the charge carriers.Thus,high-performance deep-blue PeLEDs emitting at 437 nm with a peak EQE of 0.63%are successfully demonstrated.The color coordinates are confirmed to be(0.165,0.044),which match well with the Rec.2020 standard blue gamut and have excellent spectral stability.

Fluorene pendant-functionalization of poly(N-vinylcarbazole)as deep-blue fluorescent and host materials for polymer light-emitting diodes

π-Electron coupling of pendant conjugated segment inπ-stacked semiconducting polymers always causes the formation of defect trapped sites and further quenched high-band excitons,which is harmful to the performance and stability of deep-blue polymer light-emitting diodes(PLEDs).Herein,considerate of“defect”carbazole(Cz)electromers in poly(N-vinylcarbazole)(PVK),a series of fluorene units are introduced into pendant segments(PVCz-DMeF,PVCz-FMeNPh and PVCz-DFMeNPh)to suppress the strongπ-electron coupling of pendant Cz units and enhance radiative transition toward fabricating sable PLEDs.Compared to PVCz-FMeNPh and PVCz-DFMeNPh,PVCz-DMeF spin-coated films show a relatively efficient deep-blue emission,completely similar to its single pendant chromophore,confirmed an extremely weak charge-transfer and electron coupling between adjacent pendant segments.Therefore,PLEDs based on PVCz-DMeF present stable and deep-blue emission with a high color purity(0.17,0.08),associated with extremely weak defect emission at 600∼700nm(induced by carbazole electromers).Finally,PLEDs based on PVCz-DMeF/F8BT blended films(1:1)also present the high maximum luminance(Lmax)of 6261 cd/m2 and current efficiency(CE_(max))of 2.03 cd/A,confirmed slightly trapped sites formation.Therefore,precisely control the arrangement and packing model of pendant units inπ-stacked polymer is an essential prerequisite for building efficient and stable emitter for optoelectronic devices.

Constructing an efficient deep-blue TADF emitter by host-guest interactions towards solution-processed OLEDs with narrowband emission

High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency roll-off.The CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.

Alkyl-chain branched effect on the aggregation and photophysical behavior of polydiarylfluorenes toward stable deep-blue electroluminescence and efficient amplified spontaneous emission

The control of the condensed superstructure of light-emitting conjugated polymers(LCPs)is a crucial factor to obtain high performance and stable organic optoelectronic devices.Side-chain engineering strategy is an effective platform to tune inter chain aggregation and photophysical behaviour of LCPs.Herein,we systematically investigated the alkyl-chain branched effecton the conformational transition and photophysical behaviour of polydiarylfluorenes toward efficient blue optoelectronic devices.The branched side chain will improve materials solubility to inhibit interchain aggregation in solution according to DLS and optical analysis,which is useful to obtain high quality film.Therefore,our branched PEODPF,POYDPF pristine film present high luminance efficiency of 36.1%and 39.6%,enhanced about 20%relative to that of PODPF.Compared to the liner-type sides'chain,these branched chains also suppress chain planarization and improve film morphological stability effectively.Interestingly,the branched polymer also had excellent stable amplified spontaneous emission(ASE)behaviour with low threshold(4.72μJ/cm2)and a center peak of 465 nm,even thermal annealing at 220℃in the air atmosphere.Therefore,side-chain branched strategy for LCPs is an effective means to control interchain aggregation,film morphology and photophysical property of LCPs.

Enhancement of morphological and emission stability of deep-blue small molecular emitter via a universal side-chain coupling strategy for optoelectronic device

Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular emitter with a flexible side chain always presents easily aggregation upon external treatment, and caused π-electronic coupling, which is undesirable for the efficiency and stability of deep-blue OLEDs. Herein, we proposed a side-chain coupling strategy to enhance the film morphological an emission stability of solution-processable small molecular deep-blue emitter. In contrary to “parent” MC8 TPA,the crosslinkable styryl and vinyl units were introduced as ended unit at the side-chain of Cm TPA and OEYTPA. Interestingly, Cm TPA and OEYTPA films present a relatively stable morphology and uniform deep-blue emission after thermal annealing(160 ℃) in the atmosphere, different to the discontinuous MC8 TPA annealed film. Besides, compared to the Cm TPA and OEYTPA ones, serious polaron formation in the MC8 TPA annealed film also negative to the deep-blue emission, according to transient absorption analysis. Therefore, both Cm TPA and OEYTPA annealed film obtained at 140 ℃ present an excellent deep-blue ASE behavior with a 445 nm, but absence for MC8 TPA ones, associated with the disruption of annealed films. Finally, enhancement of device performance based on Cm TPA and OEYTPA film(~40%)after thermal annealing with a similar performance curves also confirmed the assumption above. Therefore, these results also supported the effectiveness of our side-chain coupling strategy for optoelectronic applications.

Efficient and stable non-doped deep-blue organic light emitting diode based on an anthracene derivative

A new anthracene derivative 9,10-bis[3,5-di(4-tert-butylphenyl)phenyl]anthracene (BPPA) was synthesized via Suzuki coupling reaction and characterized by 1H NMR spectrum,mass spectrum,and elemental analysis.BPPA exhibits deep-blue emission both in solution and in solid thin film.This compound has a non-planar structure that results in high thermal stability and the phenomenon of polymorphism.The non-doped device based on this material shows stable deep-blue emission with the 1931 Commission international de I'Eclairage (CIE) coordinate of (0.15,0.05) under different applied voltages.The device exhibits the maximum external quantum efficiency of 2.2% at 14.9 mA/cm2 with luminance of 105 cd/m2.

Construction of deep-blue AIE luminogens with TPE and oxadiazole units

In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investigated. By linking TPE to the oxadiazole core through meta-or para-position, the intramolecular conjugation is effectively controlled. Thanks to the intelligent molecular design and specific AIE feature, when fabricated as emissive layers in non-doped OLEDs, they exhibit blue or deep-blue emission with CIE coordinates of (0.17, 0.23) and (0.15, 0.12), and good efficiencies with ηC, max and ηP, max up to 1.52 cd A-1 and 0.84 Im W-1 , shedding some light on the construction of deep-blue AIE fluorophores.

Construction of deep-blue AIE luminogens with TPE and oxadiazole units

In this paper,two AIE-active luminogens(Oxa-pTPE and Oxa-mTPE)constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal,optical and electronic properties were investigated.By linking TPE to the oxadiazole core through meta-or para-position,the intramolecular conjugation is effectively controlled.Thanks to the intelligent molecular design and specific AIE feature,when fabricated as emissive layers in non-doped OLEDs,they exhibit blue or deep-blue emission with CIE coordinates of(0.17,0.23)and(0.15,0.12),and good efficiencies with ηC,max and ηP,max up to 1.52 cd A-1and 0.84 ImW -1,shedding some light on the construction of deep-blue AIE fluorophores.

基于蒽核深蓝光材料的合成及电致发光性能

以蒽作为三线态‐三线态湮灭(TTA)型蓝光材料的基元,通过在蒽的9和10位分别引入弱给电子基团二苯并噻吩和弱吸电子基团苯氰,设计合成了两个给体‐受体型深蓝光TTA材料4‐(10‐(二苯并[b,d]噻吩‐4‐基)蒽‐9‐基)苯腈(2)和4‐(10‐(二苯并[b,d]噻吩‐2‐基)蒽‐9‐基)苯腈(3),并对它们的热稳定性、电化学性质、光物理性质及电致发光性质进行了系统表征。在纯膜状态下,两个化合物的光致发光峰分别位于445 nm和451 nm处,光致发光量子产率分别为40.2%和57.9%。基于化合物2和3的非掺杂器件的电致发光峰分别位于448 nm和458 nm处,实现了深蓝光发射。两个器件获得了较好的发光效率,其最大电流效率分别为4.2 cd·A^(-1)和6.9 cd·A^(-1),最大功率效率分别为2.3 lm·W^(-1)和3.6 lm·W^(-1),最大外量子效率分别为3.8%和5.6%。即使在1 000 cd·m^(-2)亮度下,两个器件的外量子效率依然保持在3.7%和5.4%,表现出极低的效率滚降。

以二氢苊骨架构建的深蓝光有机电致发光材料

合成了4种在二氢苊骨架上连接咔唑或三苯胺电子给体和氰基苯电子受体的发光材料,考察了电子给体连接方式及种类对材料光电性能的影响.目标化合物的单晶结构分析结果显示,位阻导致给/受体与二氢苊骨架不共平面,从而降低了共轭程度,消除了分子间π⁃π堆积作用,分子间依靠大量的C—H…π分子间相互作用稳定,只有3CzAB存在分子内π⁃π堆积作用.4种化合物均具有非常高的热稳定性,5%热失重温度(Td,5%)高于343℃.这些材料在PMMA薄膜中的发光均为深蓝光发射(403~432 nm),光致发光效率高(0.60~0.94),荧光寿命为5.4~8.6 ns.电致发光性能测试结果表明,以三苯胺为给体的材料PaAB的电致发光性能最佳,最大亮度可达2427 cd/m,峰值电流效率、功率效率和外量子效率分别为2.43 cd/A,1.53 lm/W和1.58%,色坐标(CIEx,y)为(0.15,0.09),为深蓝光发射.

Al纳米颗粒高频局域等离激元效应对BCzVBi深蓝光有机发光器件发光效率的影响

蓝紫光有机电致发光器件难以提升发光效率.本文以BCzVBi作为深蓝荧光材料,把Al纳米颗粒引入ITO/:PEDOT:PSS/TAPC/BCzVBi:BCPO/TmPyPb/Liq/Al有机发光器件的TmPyPb电子传输层,尝试用A1纳米颗粒的高频局域等离激元效应来改善此问题.在室温真空蒸镀Al膜,厚度为1 nm时,形成尺寸在10 nm量级的分散纳米颗粒.将这种颗粒膜插入TmPyPb层内距离BCzVBi:BCPO发光层x=4,8,12 nm处,与没有Al层的对比器件相比,器件的电流密度和发光亮度都会因载流子迁移率变差而下降.但在x=8 nm,两者都显著回升.其机理可能在于,x<8 nm,会产生过强的荧光淬灭,而x>8 nm,到达Al颗粒的荧光衰减过多,又难以产生足够强的局域等离子体振荡.在x=8 nm,达到最大亮度的电压(9 V)没有变化,最大亮度从4200 Cd/m^(2)降到3500 Cd/m^(2),但电流密度也从335.19 mA/cm^(2)减小到145.71 mA/cm^(2),使得电流效率反而从0.88 Cd/A提高到2.36 Cd/A,从而把外量子效率提升了170%,效率滚降比则从78%降到30.5%,压减61%.在电流密度高达270 mA/cm^(2)时,电流效率和外量子效率也能提升66.5%.这些结果表明,Al纳米颗粒高频局域表面等离激元确实能够有效增强深蓝光有机发光二极管的发光性能.

利益相关者视角下中国深远海养殖高质量发展协同机制研究

深远海养殖是拓展“蓝色粮仓”生产空间的重要抓手,明确其协同机制是保障深远海养殖高质量发展的基础。本文基于利益相关者理论,识别深远海养殖的利益相关者,构建涵盖协同动力机制、协同运行机制、协同保障机制和协同实现机制的协同机制,研究了政府、企业及科研机构等利益相关者在制度、技术和资金上如何协同,使养殖活动、技术研发、产销衔接等根据不同的现实情况进行动态调整,以制度保障推动深远海养殖高质量发展。选取“黄海冷水团绿色高效养鱼项目”为典型案例进行研究,结果表明,该项目管理体系不断规范,体现了以政府为主导的多主体参与的协同机制。未来应进一步加强资金、技术和制度保障,确保该项目的高效运作,进而为深远海养殖高质量发展提供参考。

深蓝光发射碳点的改性及在电致发光器件中的应用

深蓝色电致发光二极管(LED)在显示和照明领域中发挥着至关重要的作用。然而,目前报道的蓝色发光二极管的发射波长仅能达到460~480 nm,难以实现更短波长的发射。柠檬酸和尿素体系碳点作为一种荧光可调的发光材料,在深蓝发光方面具有优势。然而,柠檬酸尿素体系碳点是由富含亲水性官能团的小分子作为前驱体合成,因此,合成的碳点为亲水性碳点,严重限制了其在电致发光器件中应用。在此,本工作提出了一种以柠檬酸和尿素为前驱体,油胺为表面改性剂,一锅法合成疏水性碳点的方法,通过油胺中的氨基与碳点表面的羧基进行酰胺化反应,使油胺的长链烷烃包覆在碳点表面,实现疏水性碳点的可控合成,保持了碳点的深蓝光发射,并将其成功应用于电致发光器件。

我国深远海养殖业的现状特点和发展建议

在辨析深远海养殖概念的基础上,分析我国深远海养殖发展现状,归纳其具有养殖水域“深而不远”、技术装备快速迭代、产品定位走向差异化、国有资本加快进入等产业阶段特征,指出深远海养殖存在适养空间不足、产业配套薄弱、技术装备成熟度低、管理规制不健全、公共服务不完善等问题,提出优化养殖空间布局、强化养殖生产监管、构建绿色产业体系、突破关键核心技术、提升公共服务能力等发展建议,并提出现阶段推进深远海养殖业发展的具体措施。

基于螺二芴的深蓝光材料的设计合成及其表征

以芴和2-溴-芴酮为原料,通过Buchwald-Hartwig等一系列反应合成了一种具有螺二芴类的有机发光材料N-([1,1′-联苯]-3-基)-N-(9,9-二甲基-9H-芴-2-基)-2′-苯基-9,9′-螺二[芴]-2-胺,可用作蓝光OLED发光材料以及空穴传输材料.通过研究表明:目标化合物具有较好的热稳定性,其热分解温度以及熔点分别为459℃和257℃;目标化合物具有深蓝光发射(415 nm),且具有高的三线态能级,有助于增强其作为OLED发光材料的发光性能.

海洋强国视域下我国深蓝渔业发展路径研究

深蓝渔业是以现代海洋高新技术为支撑,以深远海海洋生物资源开发利用为手段的现代渔业产业体系。发展深蓝渔业对维护我国海洋权益、拓展海洋渔业发展空间、保障我国粮食安全及高水平营养供应、推动海洋科技创新与突破等具有重要意义。我国深蓝渔业已经取得显著的发展成就,但从海洋强国建设与高质量发展视角审视,深蓝渔业发展仍面临着深远海养殖环境与良种不足挑战、远洋渔业高质量发展短板多、极地渔业受装备技术与国际法制约、远海物流运输与信息保障不足、海洋气候环境变化带来新威胁等多方面问题。基于我国经济与社会体制、产业科技基础以及陆海面积广阔的优势,借鉴国际深蓝渔业发展经验,对我国深蓝渔业发展有以下建议:发挥大国优势构建深远海养殖区域化特色发展路径、发挥体制优势打造规模化深远海养殖技术经济新模式、发挥种源与生物科技优势突破深远海养殖种苗繁育、发挥制造业与工业技术优势突破深蓝渔业关键技术装备、发挥政策优势构建深蓝渔业公共服务体系、发挥海上丝绸之路优势开展深蓝渔业国际合作、发挥基础科研优势积极应对气候环境变化等。

空间电荷转移型深蓝光聚合物设计合成与性能研究

为获得具有理论100%激子利用率的深蓝色荧光发光聚合物,以N-苯基咔唑和三苯基三嗪分别作为推/拉电子单元,并修饰以乙烯基作为共聚单体,经自由基聚合获得系列不同单体配比的空间电荷转移型热激活延迟荧光聚合物。结果显示该系列聚合物具有良好的热稳定性,固体发光峰位于425 nm附近,瞬态寿命30 ns左右,稳态寿命2~10 ms,具有热激活延迟荧光发光性能,并且聚合物溶液发光表现出明显的溶剂化效应。通过改变化合物单体的配比可对其分子量、溶解性、发光峰进行调控。本文为深蓝光发光的高效发光聚合物的设计与制备提供了理论借鉴与实验依据。

蓝印花布纹样标准数据集的构建

针对在以数字化的方式传承和保护蓝印花布的技术中由于缺乏具有原始手工特征的蓝色印花图案数据集,极大地限制了深度学习技术在蓝印花布纹样识别领域的应用问题,构建了一个大规模蓝印花布纹样数据集。该数据集包含50 216张蓝印花布纹样,从动物、植物、中国神话传说及复合四大题材的角度将数据分为85个子类。该数据集的创建不仅涉及到蓝印花布的数字化建设,如蓝印花布纹样检索及相关纹样命名,还能使相关研究人员设计和验证机器学习算法。在所构建的数据集基础上,提供了4个典型深度学习网络的实验结果,以此作为其性能基准。

天宫二号数据大气细颗粒物遥感反演

针对天宫二号(TG-2)大气细颗粒物遥感反演及可行性问题,利用TG-2宽波段成像仪的可见近红外波段数据,结合MOD09A1地表反射率产品构建地表反射率库,使用6S传输模型和深蓝算法反演气溶胶光学厚度(aerosol optical depth,AOD),并结合能见度和相对湿度数据对AOD进行订正,利用统计模型估算了鲁豫皖典型地区的大气细颗粒物PM_(2.5)浓度,并对PM_(2.5)浓度的空间分布进行分析。结果表明:天宫二号数据在AOD和PM_(2.5)遥感反演中具有较高的可行性,拟合度分别达到0.910和0.902;经过垂直订正和湿度订正,PM_(2.5)和AOD之间的相关性大幅度提高;PM_(2.5)的空间分布呈“污染岛”特征,这在气溶胶排放和扩散研究中起着重要作用。天宫二号PM_(2.5)反演为区域大气污染监测提供了一种有效手段。

深海芽孢杆菌Bacillus megaterium LM-44对亚甲基蓝染料的吸附作用

以深海耐盐菌Bacillus megaterium LM-44作为微生物吸附剂,吸附偶氮染料亚甲基蓝(MB)。利用无机载体硅胶与有机载体大孔树脂对其进行固定化,通过单因素法优化吸附剂反应条件。游离菌株在最适反应条件(吸附剂浓度1.187 mg/mL、溶液pH=9、温度25℃、150 r/min、震荡反应60 min)下,对100 mg/L MB溶液的去除率为70%,吸附容量为50 mg/g,对500 mg/L MB溶液的吸附容量为153 mg/g;硅胶固定化吸附剂的在最适反应条件(吸附剂浓度2 g/L、溶液pH=9、温度25℃、150 r/min、震荡反应120 min)下,对100 mg/L MB溶液的去除率为98%,吸附容量为49 mg/g,对500 mg/L MB溶液的吸附容量为192 mg/g;大孔树脂固定化吸附剂在最适反应条件(吸附剂浓度8 g/L、溶液pH=9、温度25℃、150 r/min、震荡反应180 min)下,对100 mg/L MB溶液的去除率为82%,吸附容量为10 mg/g,对500 mg/L MB溶液的吸附容量为32 mg/g。3种形式的吸附剂在不同无机盐条件下吸附作用较为稳定。Bacillus megaterium LM-44比前期发现的脱色菌Bacillus sp.LM-24具有更高的吸附容量,且对高浓度废水仍然具有较好的去除作用。利用Langmuir与Freundlich吸附等温线模型与动力学函数对吸附过程进行研究,结果表明,3种吸附剂均与准一级动力学拟合度更高,游离菌株吸附作用与Freundlich模型拟合度更高,而固定化吸附剂与Langmuir拟合度更高。