有机-有机界面效应的原位及非原位研究

有机-有机异质结构已被广泛应用于各种有机电子器件,包括有机发光二极管(OLEDs)、有机场效应晶体管(OFETs)和有机太阳能电池等。全面理解有机-有机异质结构的界面效应,对于器件的设计和性能优化具有重要意义。然而由于有机半导体具有多样的化学特性以及分子间较弱的范德华力,界面电荷传输特性与有机-有机电子结构、环境气氛等密切相关。在此,我们报道了随着顶层半导体并五苯(pentacene)的沉积,并五苯/酞菁氧钒(VOPc)异质结构的原位实时电学性能监测。结果显示,异质结构晶体管的p型迁移率从0.4 cm2∙V−1∙s^(−1)下降至0.2 cm2∙V−1∙s^(−1),而n型迁移率从0.01 cm2∙V−1∙s^(−1)迅速增加至约0.9 cm2∙V−1∙s^(−1)。这种n型输运行为的增强归因于pentacene向VOPc的界面电子转移效应以及由此导致的VOPc层中陷阱态的填充。此外,非原位实验对比表明,当晶体管制备过程暴露于大气时会明显抑制这种界面电荷转移效应,导致沉积pentacene后n型输运几乎没有得到改善。薄膜形态、开尔文探针力显微镜(KPFM)和X射线光电子能谱(XPS)的结果表明,界面处存在从pentacene到VOPc的电子转移。进一步的密度泛函理论(DFT)计算表明,由于pentacene/VOPc之间较强的相互作用,pentacene往VOPc的电荷转移量约为0.15 e。此外,O_(2)/H2O的存在会抑制这种界面电荷转移效应,这与我们的实验结果一致。本研究通过原位电学表征对有机-有机界面之间的电荷转移效应给出了深入解释,有利于进一步的器件性能优化及界面效应分析。

Progress in octahedral spherical hohlraum study

In this paper,we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study.From our theoretical study,the octahedral spherical hohlraums with 6 Laser Entrance Holes(LEHs)of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7.In addition,the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology.We studied the laser arrangement and constraints of the octahedral spherical hohlraums,and gave a design on the laser arrangement for ignition octahedral hohlraums.As a result,the injection angle of laser beams of 50°-60°was proposed as the optimum candidate range for the octahedral spherical hohlraums.We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields,in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport.We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums,the rugby hohlraums and the cylindrical hohlraums,and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive.Up till to now,we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG)laser facilities,including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums,spherical hohlraum energetics on the SGIII prototype laser facility,and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.

Corrigendum to“First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole”[Matter Radiation Extremes 1(1)(2016)2-7]

Corrigendum Text:On page 2 of this letter,there is a misprint in the unit.The unit of the geometrical dimension of the spherical hohlraums on this page should always be“mm”rather than“mm”,i.e.in the second paragraph,“…with 800 J per beam at 0.35 mm…”should be“…with 800 J per beam at 0.35 mm…”,“The slit of 400 mm width is parallel…”should be“The slit of 400 mm width is parallel…”,“The laser focal diameter is about 500 mm…”should be“The laser focal diameter is about 500 mm…”;in the third paragraph,“…we take 850 mm as the radius…”should be“…we take 850 mm as the radius…”,“The LEH radius R_(L) is 400 mm…”should be“The LEH radius R_(L) is 400 mm…”,“…the radius of the cylindrical LEH outer ring is taken as 1.5 R_(L)=600 mm”should be“…the radius of the cylindrical LEH outer ring is taken as 1.5 R_(L)=600 mm”.This mistake does not affect any of the main results of the original letter.

First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole

The octahedral spherical hohlraums have natural superiority in maintaining high radiation symmetry during the entire capsule implosion process in indirect drive inertial confinement fusion.While,in contrast to the cylindrical hohlraums,the narrow space between the laser beams and the spherical hohlraum wall is usually commented.In this Letter,we address this crucial issue and report our experimental work conducted on the SGIII-prototype laser facility which unambiguously demonstrates that a simple design of cylindrical laser entrance hole(LEH)can dramatically improve the laser propagation inside the spherical hohlraums.In addition,the laser beam deflection in the hohlraum is observed for the first time in the experiments.Our 2-dimensional simulation results also verify qualitatively the advantages of the spherical hohlraums with cylindrical LEHs.Our results imply the prospect of adopting the cylindrical LEHs in future spherical ignition hohlraum design.

Comparison of Residential Energy Consumption in Different Geographical Areas and Relevance for Environmental Policy

Residential energy consumption is varying considerably worldwide. In order to understand these variations, and thus design effective policies for energy reductions, one needs a better understanding of the different drivers behind these variations. A comparison of geographical areas with similar climate and socio-economic conditions has shown significant variations in residential energy consumption across otherwise comparable case studies. This research paper aims to identify cultural and historical parameters that contribute to these significant variations, including economic, environmental and social traditions related to local availability of natural resources. Furthermore, the transferability of these parameters is evaluated, taking into consideration local legislation and planning documents, and historic and socio-economic accessibility of resources. It is evaluated to which degree these parameters can be transferred and included into building assessment tools and policy documents for planning and transformation of sustainable urban neighborhoods.

类液晶作为高性能有机场效应晶体管的有源层

高载流子迁移率和器件性能的一致性对于有机场效应晶体管在阵列和集成电路上的应用至关重要.然而,同时具备高性能和小批间差的方法当前仍然是个挑战.本论文在原子力显微镜和偏振荧光显微镜表征的基础上,报道了在PTCDI-C1_(3)分子模板上生长具有大晶畴的dif-TES-ADT类液晶状薄膜的方法.我们进一步将所获得的薄膜用作有机场效应晶体管的载流子传输通道,其饱和载流子迁移率高达1.62±0.26 cm^(2)V^(-1)s^(-1).更重要的是,在重复三个批次之间,每次50个器件的迁移率批间差仅为16%.这一发现为设计材料和器件结构以同时实现高载流子迁移率和器件均匀性提供了一种新思路.

High-performance organic electrochemical transistors gated with 3D-printed graphene oxide electrodes

Organic electrochemical transistors(OECTs)have garnered significant interest due to their ability to facilitate both ionic and electronic transport.A large proportion of research efforts thus far have focused on investigating high-performance materials that can serve as mixed ion doping and charge transport layers.However,relatively less attention has been given to the gateelectrode materials,which play a critical role in controlling operational voltage,redox processes,and stability,especially in the context of semiconductor-based OECTs working in accumulation mode.Moreover,the demand for planarity and flexibility in modern bioelectronic devices presents significant challenges for the commonly used Ag/AgCl electrodes in OECTs.Herein,we report the construction of high-performance accumulation-mode OECTs by utilizing a gate electrode made of three-dimensional(3D)-printed graphene oxide.The 3D-printed graphene oxide electrode incorporating one-dimensional(1D)carbon nanotubes,is directly printed using an aqueous-based ink and showcases exceptional mechanical flexibility and porosity properties,enabling high-throughput preparation for both top gates and integrated planar architecture,as well as fast ion/charge transport.OECTs with high performance comparable to that of Ag/AgCl-gated OECTs are thus achieved and present promising feasibility for electrocardiograph(ECG)signal recording.This provides a promising choice for the application of flexible bioelectronics in medical care and neurological recording.

Construction of a High-Quality Organic-Inorganic Hybrid Heterostructure and Its Photo-response Performance

The combination of metal oxide and organic semiconductor for constructing organic-inorganic hybrid heterostructure is promising to offer unique optoelectronic properties.However,the distinct difference in electron structure and processing technology of the two types of materials makes it usually difficult to fully deliver their complementary advantages.Herein,we report the construction of a high quality organic/In_(2)O_(3) hybrid heterostructure presenting a good ambipolar transport with average electron mobility>1 cm^(2)V^(-1)·s^(-1) and hole mobility up to 0.4 cm^(2)·V^(-1)·s^(-1),respectively,together with a high-gain inverter.In addition,the incorporation with organic film on top of In_(2)O_(3) remarkably reduces the dark current,enabling the realization of high photoconductivity response with photo-sensitivity of two magnitudes higher than that of pure In2O3.The photoconductor and phototransistor of the hybrid structure demonstrate high photoresponsivity>10^(3) AW^(-1) and detectivity up to 10^(14) Jones,demonstrating the promising functionality of such a high quality hybrid heterostructure.

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis.

Growth Behavior of Rubrene Thin Films on Hexagonal Boron Nitride in the Early Stage

Two-dimensional materials,with an in-plane ordered and dangling-bonding-free surface,are ideal substrates for fabricating high-quality crystalline thin films.Here,we show a systematic study on the growth of a benchmark organic semiconductor,rubrene,on hexagonal boron nitride(h-BN)substrate via physical vapor deposition from the initial amorphous phase to the final crystalline phase;the role of temperature in such transition and the epitaxy relationship between rubrene and h-BN are revealed.With the increase of substrate temperature,the critical thickness of amorphous-crystalline-transition decreases and the morphology of crystalline phase also evolves from porous to terrace-like.When substrate temperature reaches>100℃,the critical thickness reduces to only 0.5 nm and a precise layer-by-layer growth from the very first layer is achieved,which is quite rare for rubrene growing on other substrates.The high ordering can be attributed to the fine epitaxy relationship between rubrene films and the h-BN surface lattice,and this film demonstrates good charge transport ability with a p-type field-effect mobility of>1 cm^(2)·V^(-1)·s^(-1).

Interface terminal group regulated organic phototransistors with tunable persistent and switchable photoconductivity

With both light detection and intrinsic amplification functions,organic phototransistors have demonstrated promising applications,including photodetection and photomemory.To achieve excellent photoresponse and superior photogain,a common and effective strategy is to modulate the trapping effect with the purpose of reducing recombination or prolonging the lifetime of the photogenerated charge carriers.However,introducing trapping sites delicately is challenging and might sacrifice the response rate together with a typical persistent photoconductivity.Here,we demonstrate a facile strategy for achieving high photo-responsive organic phototransistors with both persistent and switchable photoconductivity features via interface terminal group regulation.By varying the terminate groups of self-assembled monolayer(SAMs)from the strong electron withdrawing group-F,neutral−CH_(3) to electron donating−NH_(2) on the dielectric surface,we realize both minority carrier trapping and majority carrier trapping in the organic phototransistor based on the C8-BTBT active layer.The electron withdrawing effect of F significantly enhances the minority carrier trapping process and yields a high photoresponsivity with a long-lasting persistent photoconductivity.In contrast,the electron donating group−NH_(2) with a distinct majority carrier trapping ability causes switchable photoconductivity so that the photocurrent can rise pronouncedly and fully decay along with light on/off.Attractively,both cases can deliver high performance with photoresponsivities higher than 104 A W^(−1) together with a photosensitivity in the level of 107 and a detectivity of approximately 10^(15)–10^(16) Jones.Such a tunable,excellent photoresponse property enables the convenient exploration of organic phototransistors to satisfy different application requirements.

Microstructured Ultrathin Organic Semiconductor Film via Dip-Coating:Precise Assembly and Diverse Applications

CONSPECTUS:Organic semiconductors(OSCs)have led to considerable progress in various fields owing to their intrinsic flexibility,adjustable chemical structures,multifunctionalities,and low processing cost.The optoelectronic properties of OSCs greatly depend on their aggregation state in molecular assemblies.To obtain ideal and reliable optoelectronic performances,a highly controlled assembly method for modulating OSC packing structures is indispensable.In particular,ultrathin OSC microstructures consisting of one to several molecular layers,known as microstructured ultrathin organic semiconductor films(MUOSFs),are of great importance for both fundamental research and applications of OSCs.However,most reported film thicknesses or molecular layer numbers of ultrathin OSC films/microstructures are“average values”rather than“real values”and are not molecularly precise.The lack of an effective and general assembly strategy seriously hinders the progress of MUOSFs.In this Account,we summarize our recent progress in exploring the assembly strategy,the underlying mechanism,and diverse applications of MUOSFs prepared via dipcoating under optimized conditions.Dip-coating,with an intrinsic three-phase contact line,has a great advantage to precisely assemble ultrathin OSC films/microstructures.As an evaporation-controlled method,the assembly processes used in dip-coating are susceptible to multiple factors,such as pulling speed,molecular structures,and solution properties.Under the guidance of our proposed“Balance Principle”for adjusting these factors,uniform and continuous MUOSFs can be obtained over a large area.Under optimized conditions,the number of molecular layers of MUOSFs can be customized with monolayer precision,which is significant for investigating the charge transport mechanism of OSCs.At the same time,the ultrathin and partial coverage characteristics of MUOSFs are beneficial to fabricate flexible and transparent devices for wearable electronics.Notably,the morphologies and coverage of ultrathin microstripes can be well tuned by the pulling speed,which is highly desired for high-performance bio/chemical sensors,because the large specific surface area provides abundant reactive sites.The feasibility and generality of our assembly method demonstrate that dip-coated MUOSFs have excellent advantages for fundamental research and applications of OSC materials,based on which many promising future works around MUOSFs can be extended to more related fields by engineering molecular orientations,packing structures,film morphologies,coverage,etc.The work on the assembly and applications of MUOSFs might offer the potential to promote the progress of organic electronics.