胺烷基侧链取代三苯胺类红光聚合物的合成及性能研究

通过Suzuki偶合反应合成了一系列胺烷基侧链取代的基于三苯胺和芴的共轭聚合物聚[4-(N,N-二甲基胺丙氧基)苯-4,4′-二苯胺-9,9-二辛基芴-4,7-二噻吩-2-基-2,1,3-苯并噻二唑](PFTD), 并对其化学结构和光电性能进行了表征. 末端胺基的存在提高了此类聚合物作为发光层应用于聚合物电致发光器件的性能(采用高功函数的金属铝作为阴极时). 结构为ITO/PVK/PFTD-5(DBT摩尔分数为5%时的聚合物)/Al的器件最大电致发射峰位于647 nm, 最大外量子效率达到了1.24%.     

基于聚芳醚的双色白光聚合物的合成与光物理及电致发光性能

采用缩聚反应,通过将深蓝光荧光团(五联芴)和橙光荧光团(4-芴基-7-(4-二苯胺基-苯基)-2,1,3-苯并噻二唑)分别链接在聚芳醚的侧链上,合成了一种双色白光电致发光聚芳醚P1,接着将一种高效浅蓝光荧光团(2,7-二(9-乙基-咔唑乙烯基)芴)引入到了P1的侧链上,得到了聚芳醚P2和P3.系统研究了这些聚芳醚材料的溶解性、热稳定性、电化学性能、光物理性能和电致发光性能等.结果表明,所有聚芳醚都具有良好的溶解性与热稳定性;薄膜态时存在明显的由深蓝光荧光团到浅蓝光荧光团及橙光荧光团的能量转移;退火前后的薄膜光致发光光谱基本一致,表明具有优秀的光谱稳定性.基于这些聚芳醚的单层电致发光器件(ITO/PEDOT:PSS/高分子/Ca/Al),利用部分能量转移和电荷俘获作用,可以实现近白光发射.器件的最大电流效率可以达到7.96 cd/A,最大亮度为9950 cd/m2,色坐标为(0.33,0.44).     

含噻吩单元的硅芴共聚物的合成及其蓝色电致发光性能

将少量(摩尔分数为1%—3％)含噻吩的窄带隙单体和宽带隙硅芴单体进行共聚, 合成了聚{9,9-二己基-3,6-硅芴-co-[2,5-二(2-甲基苯撑-4-基)-噻吩]}和聚{9,9-二己基-3,6-硅芴-co-[2,5-二(2-苯撑-4-基)-噻吩]}两类硅芴共聚物, 通过紫外-可见吸收光谱、光致发光光谱, 并制作聚合物发光二极管器件测试电致发光光谱等手段, 系统表征了两类硅芴共聚物材料的性能. 实验结果表明, 噻吩的加入形成了新的蓝色发光中心, 并且实现了从硅芴链段到含噻吩发光中心的有效能量转移. 通过增加发光中心结构的空间位阻来减小其共轭程度, 可以使聚合物的PL和EL光谱发生较大蓝移. 最终得到了效率为0.46%和色坐标(CIE)为(0.19, 0.16)的蓝光LED器件.     

一类近红外电致发光芴基共聚物的合成和性能研究

基于9,9-二辛基芴与窄带隙单体5,7-二(2-噻吩基)噻[3,4-b]并[1,4]二嗪(DTP),通过Suzuki偶合反应,合成了一系列无规窄带隙的芴基共聚物(PFO-DTP),并对它们的紫外-可见吸收光谱、光致发光和电致发光性能进行了初步研究.共聚物在380 nm和632 nm处有两个明显的吸收峰,其中632 nm处的吸收随着共聚物中窄带隙单体(DTP)含量的增加而加强,最大电致发光峰随着共聚物中窄带隙单体(DTP)含量的增加,从752nm红移到了781 nm.同时与其同分异构体4,7-二(2-噻吩基)苯并噻二唑(DBT)与芴的共聚物PFO-DBT相比,该类聚合物的吸收红移,与近地太阳光谱更为匹配.     

给体-受体-给体窄带隙染料掺杂聚芴发光二极管

合成了一系列给体-受体-给体型窄带隙荧光分子, 并将其作为掺杂剂与主体(Host)宽带隙聚芴共混制备发光二极管. 荧光分子为4,7-二呋喃-苯并噻二唑(O-S)、4,7-二噻吩-苯并噻二唑(S-S)、4,7-二(N-甲基吡咯)-苯并噻二唑(N-S)、4,7-二硒吩-苯并噻二唑(Se-S)和4,7-二(N-甲基吡咯)-苯并硒二唑(N-Se). 溶液中荧光分子的紫外-可见吸收峰位于447~472 nm, 荧光发射峰位于563~637 nm. 该系列荧光分子掺杂聚芴(PFO)发光器件的电致发光峰位于580~633 nm. 当器件结构为ITO/PEDOT/PVK/PFO+N-Se/Ba/Al时, 最大外量子效率为1.28%, 电流效率1.31 cd/A.     

基于苯并噻二唑和硅芴的一系列红光材料的载流子传输性质及荧光性质(英文)

用密度泛函理论(DFT)方法研究了基于苯并噻二唑和硅芴的一系列聚合物的基态和激发态结构、传输和荧光性质.聚合物的能隙、电离能、电子亲和势、最低激发能以及吸收光谱通过外推法得到.结果表明空穴、电子注入和传输性质受苯并噻唑在硅芴上的位置以及正丁基在噻吩上的位置影响很大.(SiF2-DHTBT1-m)n和(SiF1-DHTBT1-m)n(SiF和DHTBT分别代表硅芴和4,7-二(2-噻吩基)-2,1,3-苯并噻二唑)表现出较好的空穴和电子注入性质,而(SiF1-DHTBT1-o)n和(SiF1-DHTBT1-p)n的电荷注入性质较差.除(SiF1-DHTBT1-o)n外,聚合物的荧光光谱处于红光范围.     

侧链含金属铱配合物的电磷光白光聚合物

设计了一系列新型芴-咔唑电磷光共轭聚合物.通过共价键将双(2-(9,9-二乙基-9H-芴-2-基)吡啶-N,C2’)合铱(III)(Ir Fpy)接枝到3,6-二溴咔唑的N-烷基侧链,采用Suzuki缩聚反应合成了铱配合物(Ir Fpy)含量分别为0.25 mol%,0.5 mol%和1 mol%的聚合物PF-Ir Fpy.当引入的配合物Ir Fpy含量为1 mol%时,得到的共轭聚合物发射色坐标为(0.44,0.56)的黄光.随着接枝的铱配合物Ir Fpy在共轭聚合物中含量降低,作为主体的聚(9,9-二辛基芴)蓝光发射不能被完全淬灭,得到共聚物同时发射主体蓝光及客体铱配合物黄光的单分子白光共轭聚合物.共聚物发光器件结构为ITO/PEDOT:PSS(50 nm)/polymer+PBD(30 wt%)(80nm)/Ba(4 nm)/Al(150 nm)[氧化铟锡/苯磺酸掺杂聚乙烯基二氧噻吩/聚合物+(2,4-二苯-5-4-叔丁基苯-1,3,4-噁二唑)(w=30%)/钡/铝],基于共聚物PF-Ir Fpy025的器件流明效率为3.97 cd/A,色坐标为(0.34,0.34),非常接近于标准白光发射的色坐标(0.33,0.33).为了研究采用共聚物PF-Ir Fpy025和PF-Ir Fpy05制备的白光器件的光谱稳定性,测试了外加电压在8~13 V范围内的EL光谱,当外加电压从8 V升高到13 V时,两个EL器件都表现出了良好的EL光谱稳定性.研究结果表明,在共轭聚合物侧链上引入螯合金属铱配合物单元是实现高效、稳定的白光电致磷光器件的有效方法之一.     

芴-呋喃苯并噻二唑共聚物的光电性能

对芴-呋喃苯并噻二唑共聚物的吸收光谱、光致发光光谱、电致发光性能和光伏性能进行了研究. 共聚物在382 nm和530 nm处有两处明显的吸收峰, 其中530 nm处的吸收强度随着共聚物中呋喃苯并噻二唑单元(FBT)含量的增加而增加. 随着FBT单元含量的增加, 电致发光峰值从611 nm红移至702 nm. 以PVK为空穴传输层, 共聚物PFO- FBT0.1为发光层的发光器件, 在33 mA/cm2电流密度下的外量子效率达2.32%, 亮度为441 cd/m2. 实验中观察到快速的链内能量陷阱过程(从芴到FBT单元). 以共聚物PFO-FBT50为电子给体、PCBM为电子受体(重量比1:2)共混制备的光电池能量转换效率为1.13%, 开路电压0.85 V, 短路电流3.39 mA/cm2, 光谱响应边延伸至近750 nm.     

含有萘并噻二唑的红光电致发光聚合物的合成和性能研究

以2,7-二溴-9,9-双(N,N-二甲基丙胺基)芴与4,7-双(5-溴-2-噻吩)-2,1,3-萘并噻二唑为共聚单体, 通过Suzuki偶合反应合成按不同比例共聚的一系列共轭聚合物, 并对它们的电致发光性能进行了研究. 结果表明, 所有的聚合物均在高功函数金属铝作阴极的器件中具有较高的发光效率, 最大电致发光外量子效率为1.3%, 好于目前广泛应用的低功函数金属(如钡, 钙等)作阴极的发光效率.     

基于荧光共轭聚合物的金属离子传感研究

设计合成了一系列结构相似的共轭主链含5%苯并噻二唑结构单元及侧链带胺类金属离子螯合基团的阴离子型水溶性共轭聚合物PFA, PFBTA和PFBTNA, 并对它们在不同极性溶剂中的光物理性质进行了研究. 利用分子主链含适量苯并噻二唑共聚单元的聚芴衍生物聚集态不同荧光光谱及颜色发生显著变化这一特性, 研究了这一系列水溶性聚芴衍生物在水/甲醇(9/1)溶液中对金属离子的荧光响应过程. 结果表明, 金属离子不仅能通过能量及电荷转移猝灭聚合物荧光, 还可以通过静电相互作用力使聚合物聚集态发生改变, 进而影响聚合物的光学性质. 同时分子链上引入金属离子螯合基团能够显著提高体系的检测灵敏度, 聚合物PFBTA和PFBTNA可以特异性识别Cu²⁺离子, 并且可做为其它金属离子的广谱型比色法检测材料.     

Aromatic Gain in a Supramolecular Polymer

The synergy of aromatic gain and hydrogen bonding in a supramolecular polymer is explored. Partially aromatic bis(squaramide) bolaamphiphiles were designed to self‐assemble through a combination of hydrophobic, hydrogen‐bonding, and aromatic effects into stiff, high‐aspect‐ratio fibers. UV and IR spectroscopy show electron delocalization and geometric changes within the squaramide ring indicative of strong hydrogen bonding and aromatic gain of the monomer units. The aromatic contribution to the interaction energy was further supported computationally by nucleus‐independent chemical shift (NICS) and harmonic oscillator model of aromaticity (HOMA) indices, demonstrating greater aromatic character upon polymerization: at least 30 % in a pentamer. The aromatic gain–hydrogen bonding synergy results in a significant increase in thermodynamic stability and a striking difference in aggregate morphology of the bis(squaramide) bolamphiphile compared to isosteres that cannot engage in this effect.     

Optical Gain in Semiconducting Polymer Nano and Mesoparticles

The presence of excited-states and charge-separated species was identified through UV and visible laser pump and visible/near-infrared probe femtosecond transient absorption spectroscopy in spin coated films of poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) nanoparticles and mesoparticles. Optical gain in the mesoparticle films is observed after excitation at both 400 and 610 nm. In the mesoparticle film, charge generation after UV excitation appears after around 50 ps, but little is observed after visible pump excitation. In the nanoparticle film, as for a uniform film of the pure polymer, charge formation was efficiently induced by UV excitation pump, while excitation of the low energetic absorption states (at 610 nm) induces in the nanoparticle film a large optical gain region reducing the charge formation efficiency. It is proposed that the different intermolecular interactions and molecular order within the nanoparticles and mesoparticles are responsible for their markedly different photophysical behavior. These results therefore demonstrate the possibility of a hitherto unexplored route to stimulated emission in a conjugated polymer that has relatively undemanding film preparation requirements.     

Asymmetric AZA-BODIPY with Optical Gain in the Near-Infrared Region

In recent years, there has been a lot of interest in the development of organic compounds emitting in the near-infrared (NIR) region due to their stimulating applications, such as biosensing and light detection and ranging (LiDAR). Moreover, a lot of effort has been devoted to finding organic emitters with optical gain in the NIR region for lasing applications. In this paper, we present the ultrafast spectroscopy of an asymmetric AZA-BODIPY molecule that shows relevant photophysical changes moving from a diluted solution to a concentrated solution and to a spin-coated film. The diluted solution and the spin-coated film show a bleaching band and a stimulated emission band in the visible region, while the very concentrated solution displays a broad (150 nm) and long-living (more than 400 ps) optical gain band in the NIR region, centered at 900 nm. Our results pave the way for a new organic laser system in a near-infrared spectral region.     

如何获得气体反应的最高平衡产率

本文以合成氨反应为例,采用近似计算和用Maple计算2种方法证明当原料气的配比符合方程式的计量系数之比时可以得到最高平衡产率。     

失之东隅收之桑榆——从“实验失败”中引导本科生的实验探究和创新能力

Failed experiments occur frequently in laboratory. How the laboratory teacher actively and effectively deal with the failed experiments and guide students plays an important role in the cultivation of undergraduates' creativity. If he loses on the swings, he may win on the roundabouts. We show how teacher guide and enlighten the undergraduate students to get the inspiration and learn from the failed experiments by two examples of Chemistry Laboratory of undergraduates. Let the students find problems with curiosity, analyze problems, and solve the problem in the "experiment-failure-improvement-experiment" process based on relevant knowledge and rules. The teaching and learning efficiency of laboratory class is significantly improved. Undergraduates not only have a profound discussion and analysis of experimental results, but also receive effective training in scientific research literacy and quality.     

量子阱单激子光增益实现超低阈值连续波激光

胶质纳米晶光增益材料对于开发新一代的高效激光器前景巨大.采用外延生长法制备原子尺寸厚度的Ⅱ型CdSe/CdTe复合纳米片,研究该异质结构的光学性质及其对应的电荷动力学过程,以此探讨其光增益性能及激光应用潜能.光谱结果表明,Ⅱ型纳米片有效的电子与空穴分离结构使其表现出较大的斯托克斯位移（△_S=100 meV）和较强的激子-激子库伦排斥力（△_XX=50 meV）.△_S和△_XX的协同效应使"激子-双激子"吸收能相比单激子发射能提高了约150 meV,打破了一般纳米晶结构中两者的简并关系,这将有效抑制光吸收损失并促进单激子光增益.单激子光增益机制下该纳米片较长的单激子寿命（τ_x=394 ns）使连续激光泵浦的理论功率阈值低至12 W/cm²,这为开发实用性更强的、超低阈值的连续波激光器提供可能.     

Enhanced Gain in Organic Photodetectors Using the Polymer with Singlet Open-Shell Ground State

Photodetectors are critical components in intelligent optoelectronic systems, and photomultiplication-capable devices are essential for detecting weak optical signals. Despite significant advances, developing photomultiplication-type organic photodetectors with high gain and low noise current simultaneously remains challenging. In this work, a new conjugated polymer PDN with singlet open-shell ground state is introduced in active layers for electron capture, and the corresponding PDN-based photodetectors exhibited an enhanced photoelectric gain and decreased dark current density at a low forward bias. At 1.5 V, the PDN-based ternary photodetector has the external quantum efficiency (EQE) up to 2552.3 % and the specific detectivity of 1.4×10¹⁴ Jones at 710 nm calculated by the measured noise current, with the gain 22 times higher than that of the control group. This study provides an approach for exploiting polymers with singlet open-shell ground state to enhance the gain of organic photodetectors.     

Rethinking Uncaging: A New Antiaromatic Photocage Driven by a Gain of Resonance Energy

Photoactivatable compounds for example photoswitches or photolabile protecting groups (PPGs, photocages) for spatiotemporal light control, play a crucial role in different areas of research. For each application, parameters such as the absorption spectrum, solubility in the respective media and/or photochemical quantum yields for several competing processes need to be optimized. The design of new photochemical tools therefore remains an important task. In this study, we exploited the concept of excited-state-aromaticity, first described by N. Colin Baird in 1971, to investigate a new class of photocages, based on cyclic, ground-state-antiaromatic systems. Several thio- and nitrogen-functionalized compounds were synthesized, photochemically characterized and further optimized, supported by quantum chemical calculations. After choosing the optimal scaffold, which shows an excellent uncaging quantum yield of 28 %, we achieved a bathochromic shift of over 100 nm, resulting in a robust, well accessible, visible light absorbing, compact new photocage with a clean photoreaction and a high quantum product (ϵ⋅Φ) of 893 M⁻¹ cm⁻¹ at 405 nm.     

Gain measurements in a transverse-flowing NaN2O + CO chemical laser

N₂O laser gain profiles in a low-pressure Na-catalyzed N₂OCO transverse-flow chemical laser have been measured for a variety of flow conditions. The small-signal gain depends on the CO/N₂O ratio with a maximum of about 0.005 cm^?1 measured to date. Analysis of emission spectra and computer modelling of the gain profiles indicate that 15-20% of the chemical energy is available for laser pumping, yielding a specific laser energy of approximately 210 J/mole of mixture.