Regioisomeric Polymer Semiconductors Based on Cyano-Functionalized Dialkoxybithiophenes:Structure-Property Relationship and Photovoltaic Performance

Cyano substitution is vital to the molecular design of polymer semiconductors toward highly efficient organic solar cells.However,how regioselectivity impacts relevant optoelectronic properties in cyano-substituted bithiophene systems remain poorly understood.Three regioisomeric cyano-functionalized dialkoxybithiophenes BT_(HH),BT_(HT),and BT_(TT) with headto-head,head-to-tail,and tail-to-tail linkage,respectively,were synthesized and characterized in this work.The resulting polymer semiconductors(PBDTBTs)based on these building blocks were prepared accordingly.The regiochemistry and property relationships of PBDTBTs were investigated in detail.The BTHH moiety has a higher torsional barrier than the analogs BT_(HT) and BT_(TT),and the regiochemistry of dialkoxybithiophenes leads to fine modulation in the optoelectronic properties of these polymers,such as optical absorption,band gap,and energy levels of frontier molecular orbitals.Organic field-effect transistors based on PBDTBT_(HH) had higher hole mobility(4.4×10^(-3) cm^(2)/(V·s))than those(ca.10^(-4) cm^(2)/(V·s))of the other two polymer analogs.Significantly different short-circuit current densities and fill factors were obtained in polymer solar cells using PBDTBTs as the electron donors.Such difference was probed in greater detail by performing space-charge-limited current mobility,thin-film morphology,and transient photocurrent/photovoltage characterizations.The findings highlight that the BTHH unit is a promising building block for the construction of polymer donors for highperformance organic photovoltaic cells.

Intrinsically stretchable polymer semiconductor based electronic skin for multiple perceptions of force,temperature,and visible light

As a stretchable seamless device,electronic skin(E-skin)has drawn enormous interest due to its skin-like sensing capability.Besides the basic perception of force and temperature,multiple perception that is beyond existing functions of human skin is becoming an important direction for E-skin developments.However,the present E-skins for multiple perceptions mainly rely on different sensing materials and heterogeneous integration,resulting in a complex device structure.Additionally,their stretchability is usually achieved by the complicated microstructure design of rigid materials.Here,we report an intrinsically stretchable polymer semiconductor based E-skin with a simple structure for multiple perceptions of force,temperature,and visible light.The E-skin is on the basis of poly(3-hexylthiophene)(P3HT)nanofibers percolated polydimethylsiloxane(PDMS)composite polymer semiconductor,which is fabricated by a facile solution method.The E-skin shows reliable sensing capabilities when it is used to perceive strain,pressure,temperature,and visible light.Based on the E-skin,an intelligent robotic hand sensing and controlling system is further demonstrated.Compared with conventional E-skins for multiple perceptions,this E-skin only has a simple monolayer sensing membrane without the need of combining different sensing materials,heterogeneous integration,and complicated microstructure design.Such a strategy of utilizing intrinsically stretchable polymer semiconductor to create simple structured E-skin for multiple perceptions will promote the development of E-skins in a broad application scenario,such as artificial robotic skins,virtual reality,intelligent gloves,and biointegrated electronics.

Achieving Synergistic Improvement in Dielectric and Energy Storage Properties of All-Organic Poly(Methyl Methacrylate)-Based Copolymers Via Establishing Charge Traps

How to achieve synergistic improvement of permittivity(ε_(r))and breakdown strength(E_(b))is a huge challenge for polymer dielectrics.Here,for the first time,theπ-conjugated comonomer(MHT)can simultaneously promote theε_(r)and E_(b)of linear poly(methyl methacrylate)(PMMA)copolymers.The PMMA-based random copolymer films(P(MMA-co-MHT)),block copolymer films(PMMA-b-PMHT),and PMMA-based blend films were prepared to investigate the effects of sequential structure,phase separation structure,and modification method on dielectric and energy storage properties of PMMA-based dielectric films.As a result,the random copolymer P(MMA-coMHT)can achieve a maximumε_(r)of 5.8 at 1 kHz owing to the enhanced orientation polarization and electron polarization.Because electron injection and charge transfer are limited by the strong electrostatic attraction ofπ-conjugated benzophenanthrene group analyzed by the density functional theory(DFT),the discharge energy density value of P(MMA-co-PMHT)containing 1 mol%MHT units with the efficiency of 80%reaches15.00 J cm^(-3)at 872 MV m^(-1),which is 165%higher than that of pure PMMA.This study provides a simple and effective way to fabricate the high performance of polymer dielectrics via copolymerization with the monomer of P-type semi-conductive polymer.

Photoswitchable semiconducting polymer dots with photosensitizer molecule and photochromic molecule loading for photodynamic cancer therapy

Photodynamic therapy(PDT)is a new and rapidly developing treatment modality for dinical cancer therapy.Semiconductor polymer dots(Pdots)doped with photosensitizers have been successfully applied to PDT,and have made progress in the field of tumor therapy.However,the problems of severe photosensitivity and limited tisue penetration depth are needed to be solved during the implementation process of PDT.Here we developed the Pdots doped with photosensitizer molecule Chlorin e6(Ce6)and photochromic molecule 1,2-bis(2,4-dimethy1-5 phenyl-3-thiophene)-3,3,4,5-hexafuoro-1-cyclopentene(BTE)to construct a photoswitchable nanoplatform for PDT.The Ce6-BTE-doped Pdots were in the green region,and the tissue penetration depth was increased compared with most Pdots in the blue region.The reversible conversion of BTE under different light irradiation was utilized to regulate the photodynamic effect and solve the problem of photosensitivity.The prepared Ce6-BTE-doped Pdots had small size,excellent optical property,efficient ROS generation and good photoswitchable ability.The cellular uptake,cytotoxicity,and photodynamic effect of the Pdots were detected in human colon tumor cells.The experiments in vitro indicated that Ce6-BTE-doped Pdots could exert excellent photodynamic effect in ON state and reduce photosensitivity in OFF state.These results demonstrated that this nanoplatform holds the potential to be used in clinical PDT.

Diketopyrrolopyrrole-based Conjugated Polymers as Representative Semiconductors for High-Performance Organic Thin-Film Transistors and Circuits

Since the first report of diketopyrrolopyrrole(DPP)-based conjugated polymers for organic thin-film transistors(OTFTs),these polymers have attracted great attention as representative semiconductors in high-performance OTFTs.Through unremitting efforts in molecular-structure regulation and device optimization,significant mobilities exceeding 10 cm2·V–1·s–1 have been achieved in OTFTs,greatly promoting the applied development of organic circuits.In this review,we summarize our progress in molecular design,synthesis and solution-processing of DPP-based conjugated polymers for OTFT devices and circuits,focusing on the roles of design strategies,synthesis methods and processing techniques.Furthermore,the remaining issues and future outlook in the field are briefly discussed.

界面材料PFN-Br的光放大性质及其在电泵浦有机激光中的应用潜力

系统研究了水/醇溶性共轭聚电解质Poly[(9,9-bis(3′-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)]dibromide(PFN-Br)的光放大性质,发现其具有较小的放大自发辐射(ASE)阈值(~11μJ/cm^(2))和ASE截止厚度(<50 nm),是一种高效的蓝光(~456 nm)增益介质.利用其对于有机溶剂的良好耐性,如甲苯等,分别在石英和ITO玻璃基底上制备了PFN-Br/F8BT以及PFN-Br/MEH-PPV双层器件.经过研究发现,PFN-Br界面层不会明显增加系统损耗并影响上层F8BT的光增益.然而,在ITO玻璃基底上,通过引入PFN-Br界面层,减少了ITO电极对MEH-PPV增益介质损耗,显著地降低了其ASE阈值(相比于没有PFN-Br界面降低约60%).这些发现说明了PFN-Br本身具备良好的增益性能,同时也是成熟的载流子传输界面功能材料,在有机激光领域应用前景十分广泛.

石墨相氮化碳的化学合成及应用

石墨相氮化碳(g-C_3N_4)具有独特的电子结构和优异的化学稳定性,近年来不仅被作为不含金属组分的催化剂和催化剂载体,广泛地应用于有机官能团的选择性转换、光催化分解水、氧还原和Au、Pd、Ag、Pt等贵金属的负载,还被作为绿色储能材料和硬模板剂用于H_2、CO_2的存储和纳米金属氮(氧)化物的制备等,在能源和材料相关领域逐渐引起人们的关注.本文将从材料的制备和应用角度,综述国内外同行近年来在g-C_3N_4研究中所取得的一些重要进展,并对其未来发展趋势,特别是在能源和环境领域中的应用进行了展望.

无机半导体材料光引发高分子聚合的发展及前景

在总结具有光催化功能的无机半导体材料发展概况的基础上,综述了使用典型无机半导体材料,包括TiO2、ZnO和CdS,进行光引发高分子聚合反应的研究概况。并指出了目前对无机半导体光引发聚合反应的研究所存在的几个主要问题:只研究了少数具有紫外引发活性的无机半导体的引发反应;无机半导体引发剂的使用方式单一;聚合单体、聚合反应类型有待进一步扩展研究。最后针对这些问题提出了几点建议,并预言了其潜在的应用。

Solvent-vapour treatment induced performance enhancement of amplified spontaneous emission based on poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene]

In this work, performance enhancements of amplified spontaneous emission （ASE） from poly[2-methoxy-5-（2＇- ethyl-hexyloxy）-l,4-phenylene vinylene] （MEH-PPV） have been achieved via solvent vapour treatment. Correlations between the morphology of the film and the optical performance of polymer-based ASE are investigated. The active layers are characterised by atomic force microscopy and optical absorption. The results show that the solvent-vapour treatment can induce the MEH-PPV self-organisation into an ordered structure with a smooth surface, leading to enhanced optical gain. Thus the solvent-vapour treatment is a good method for improving the optical properties of the MEH-PPV.

Amplified spontaneous emission from metal-backed poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] film

We investigate the amplified spontaneous emission （ASE） from an Ag-backed poly[2-methoxy-5-（2＇-ethylhexyloxy）- 1,4-phenylenevinylene] （MEH-PPV） film with different film thicknesses. The ASE characteristics of Ag-backed MEH- PPV films with different thicknesses show that increasing the film thickness can reduce the influence of the Ag cladding. The threshold, the gain, and the loss of the device with a thickness of 170 nm are comparable to those of a metal-free device. The lasing threshold of this device is about 7.5 times that of a metal-free device. Our findings demonstrate that Ag-backed MEH-PPV film with an appropriate thickness can still be a good polymer gain material for the fabrication of solid-state lasers.

Effect of different metal-backed waveguides on amplified spontaneous emission

We investigate the effect of a metallic electrode on the ability for poly[2-methoxy-5-（2＇-ethylhexyloxy）-1,4- phenylene vinylene] （MEH-PPV） film to undergo amplified spontaneous emission （ASE）. The threshold of the device with Ag cladding is about 10 times greater than that of a metal-free device, but metal such as Al completely shuts off ASE. The ASE recurs when a thin spacer layer, such as a few nanometers of SiO2, is introduced between the MEH-PPV film and the Al cladding. Compared with the Cu or Al electrode, the Ag cladding is most suited to serve as an electrode with its low optical loss due to its high work-function and reflectivity.

硬模板法制备聚合物半导体氮化碳

聚合物半导体石墨相氮化碳(g-C_3N_4),作为一种非金属可见光光催化剂,在太阳能转化和环境保护方面有着巨大的潜在应用。由于其具有高物理化学稳定性及独特的光捕获性能,可以直接将低密度的太阳能转化为高密度的化学能,或直接降解有机污染物,因此,g-C_3N_4制备和性能的研究引起了国内外研究人员的广泛关注。研究表明,用不同方法和化学工艺对氮化碳在结构上进行改进,可以获得新的理化性质,提高氮化碳的光催化效率,筛选出在特定反应下高效率的氮化碳结构。硬模板法制备g-C_3N_4纳米材料,可以有效地提高其表面积,促进光捕获和光生电子传递,进一步提高光催化效率。今对硬模板法制备氮化碳及研究现状进行了详细介绍,同时对g-C_3N_4光催化剂的发展趋势进行了展望。

染料增感聚苯胺半导体薄膜的光电性能

采用电化学方法，利用有机染料对聚苯胺进行有机染料增感，制备出不同增感性能的聚苯胺薄膜。采用红外吸收光谱对增感后的聚苯胺的结构和性能进行了表征，对其在紫外－ 可见光区的吸收特性进行了研究。结果表明，染料增感后的聚合物薄膜电导率分别为：直接耐晒蓝增感为０ ．１４２ Ｓ／ｃｍ ；直接耐晒翠蓝增感为１ ．０５０ Ｓ／ｃｍ ；直接耐晒黑增感为０ ．７９６ Ｓ／ｃｍ ； 四羧基酞菁增感为１ ．２２０ Ｓ／ｃｍ 。这些增感均可使聚苯胺在可见光谱范围内的光吸收增强，较大幅度地改善聚苯胺的光谱响应范围。

High-Mobility Ambipolar Benzodifurandione-Based Copolymers with Regular Donor–Acceptor Dyads Synthesized via Aldol Polycondensation

In this study,a family of three benzodifurandione-baseddonor–acceptor(D–A)copolymers,namelypoly[3,7-bis((E)-1-(4-octadecyldocosyl)-2-oxo-6-yl-indolin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dionealt-(E)-1,2-di(2,2′-bithiophen-5-yl)ethene](PBDO-DTE),poly[3,7-bis((E)-7-fluoro-1-(4-octadecyldocosyl)-2-oxo-6-yl-indolin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione-alt-(E)-1,2-di(2,2′-bithiophen-5-yl)ethene](PFBDO-DTE),and poly[(3E,7E)-3,7-bis(1-(4-octadecyldocosyl)-2-oxo-6-yl-1,2-dihydro-3Hpyrrolo[2,3-b]pyridin-3-ylidene)-3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione-alt-(E)-1,2-di(2,2′-bithiophen-5-yl)ethene](PNBDO-DTE),was designed and synthesized by employing aldol polycondensation reactions between benzodifurandione and bisindolin-2-ones in high yields.Further incorporation of fluorine or sp2-hybridized nitrogen atoms on the bisindolin-2-one unit induced S…F or S…N nonbonding interactions-locked polymeric conjugated backbones for PFBDO-DTE and PNBDO-DTE,respectively.Ultraviolet photoelectron spectroscopy and inverse photoemission spectroscopy measurements revealed that the two copolymers have lower frontier molecular orbitals than that of PBDO-DTE.Atomic force microscopy and two-dimensional grazing-incidence wide-angle X-ray scattering investigations indicated the PNBDO-DTE copolymer could form more ordered molecular aggregation in the solid state than PBDO-DTE and PFBDO-DTE copolymers.We fabricated thin film transistors based on these copolymers on plastic polyethylene terephthalate substrates,and they all showed ambipolar charge transport characteristics.Among them,the PNBDO-DTE-based devices afforded optimal charge transport characteristics with high hole and electron mobilities of 5.16 and 1.33cm^(2)V^(−1)s^(−1),respectively.Our study highlights that aldol polycondensation would be an extremely useful protocol in constructing high-performance polymer semiconductors.

全印刷制备有机薄膜晶体管:进展与挑战

近几十年来,有机薄膜晶体管由于自身优异的柔性、溶液加工、物化性质可调、基底适用性广等优势在柔性显示、全贴合传感器阵列等现代电子产业领域展现着远超常规硅基薄膜晶体管的应用潜力。因有机薄膜晶体管溶液加工的特征,其制备可与多种印刷技术高度整合,尤其是晶体管沟道的活性层印刷。从有机薄膜晶体管的全印刷制备出发,探讨并总结了多种可用于晶体管制备的印刷策略,包括丝网印刷技术、刮涂印刷技术、凹版印刷技术、喷墨印刷技术以及其他印刷策略;还总结了薄膜晶体管不同部件的可印刷油墨材料,包括用于印刷金属电极的金属纳米颗粒油墨、可用于印刷介电层的高介电常数交联型高分子油墨、可用于印刷晶体管沟道的碳基、共轭小分子基、共轭聚合物基油墨;此外,根据晶体管的工作模式进一步讨论了可实现全印刷制备的有机薄膜晶体管类型,包括有机场效应晶体管、电解质门控有机晶体管、有机电化学晶体管。最后,对有机薄膜晶体管及更复杂电路在全印刷制备中的挑战和未来研究方向进行了展望。

Effect of Dopant Properties on the Microstructures and Electrical Characteristics of Poly（3-Hexylthiophene） Thin Films

Effects of dopant properties on microstructures and the electrical characteristics of poly （3-hexylthiophene） （P3HT） films are studied by doping 0.1 wt% 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane （F4？TCNQ）, 6,6-phenyl-C61butyric acid methyl ester （PCBM） and N,N＇？Diphenyl-N,N＇-（m-tolyl）-benzidine （TPD） into P3HT, respectively. The introductions of various dopants in small quantities increase the field-effect mobility and the I on/Ioff ratio of P3HT thin-film transistors. However, each of dopants shows various effects on the crystalline order and the molecular orientation of P3HT films and the performance of P3HT thin-film transistors. These can be attributed to the various size, shape and energy-level properties of the dopants.

Soft multifunctional neurological electronic skin through intrinsically stretchable synaptic transistor

Neurological electronic skin(E-skin)can process and transmit information in a distributed manner that achieves effective stimuli perception,holding great promise in neuroprosthetics and soft robotics.Neurological E-skin with multifunctional perception abilities can enable robots to precisely interact with the complex surrounding environment.However,current neurological E-skins that possess tactile,thermal,and visual perception abilities are usually prepared with rigid materials,bringing difficulties in realizing biologically synapse-like softness.Here,we report a soft multifunctional neurological E-skin(SMNE)comprised of a poly(3-hexylthiophene)(P3HT)nanofiber polymer semiconductor-based stretchable synaptic transistor and multiple soft artificial sensory receptors,which is capable of effectively perceiving force,thermal,and light stimuli.The stretchable synaptic transistor can convert electrical signals into transient channel currents analogous to the biological excitatory postsynaptic currents.And it also possesses both short-term and long-term synaptic plasticity that mimics the human memory system.By integrating a stretchable triboelectric nanogenerator,a soft thermoelectric device,and an elastic photodetector as artificial receptors,we further developed an SMNE that enables the robot to make precise actions in response to various surrounding stimuli.Compared with traditional neurological E-skin,our SMNE can maintain the softness and adaptability of biological synapses while perceiving multiple stimuli including force,temperature,and light.This SMNE could promote the advancement of E-skins for intelligent robot applications.

氮化碳聚合物半导体光催化

半导体光催化技术通过太阳光驱动一系列重要的化学反应,将低密度的太阳能转化为高密度的化学能或直接降解和矿化有机污染物,在解决能源短缺和环境污染等问题方面具有重要的应用前景。最近,聚合物半导体石墨相氮化碳(g-C3N4),由于优异的化学稳定性和独特的电子能带结构,被作为一种廉价、稳定、不含金属组分的可见光光催化剂广泛应用于太阳能的光催化转化,如光解水产氢产氧、有机选择性光合成和有机污染物的降解等,引起人们的关注。本文将围绕g-C3N4光催化剂的改性研究,综述国内外近年来在g-C3N4光催化领域所取得一些重要进展,比如理论研究g-C3N4的组成结构及化学性质、金属/非金属掺杂调控g-C3N4的半导体能带结构、软/硬模板法优化g-C3N4的纳米结构、表面化学修饰改进g-C3N4的表面反应动力学过程及半导体复合提高光生载流子的分离效率等。最后,本文还对g-C3N4光催化的未来发展趋势进行展望。

Synergistic Effects of Solvent Vapor Assisted Spin-coating and Thermal Annealing on Enhancing the Carrier Mobility of Poly(3-hexylthiophene)Field-effect Transistors

Poly(3-hexylthiophene)(P3HT)thin films,obtained by normal spin-coating and solvent vapor assisted spin-coating(SVASP)before and after thermal annealing(TA),and the corresponding devices were prepared to unravel the microstructure-property relationship,which is of great importance for the development of organic electronics.When SVASP-TA films were used as the active layers of the organic field-effect transistors,a hole mobility up to 0.38 cm^(2)·V^(-1)·s^(-1)was achieved.This mobility was one of the highest values and one order of magnitude higher than that of the normal spin-coating films based transistors.The relationship between the microstructure and the device performance was fully investigated by UV-Vis absorption spectra,grazing incident X-ray diffraction(GIXD),and atomic force microscopy(AFM).The impressive mobility was attributed to the high crystallinity and ordered molecule packing,which stem from the synergistic effects of SVASP and thermal annealing.

Recent advances in developing high‑performance organic hole transporting materials for inverted perovskite solar cells

Inverted perovskite solar cells(PVSCs)have recently made exciting progress,showing high power conversion efciencies(PCEs)of 25%in single-junction devices and 30.5%in silicon/perovskite tandem devices.The hole transporting material(HTM)in an inverted PVSC plays an important role in determining the device performance,since it not only extracts/transports holes but also afects the growth and crystallization of perovskite flm.Currently,polymer and self-assembled monolayer(SAM)have been considered as two types of most promising HTM candidates for inverted PVSCs owing to their high PCEs,high stability and adaptability to large area devices.In this review,recent encouraging progress of high-performance polymer and SAM-based HTMs is systematically reviewed and summarized,including molecular design strategies and the correlation between molecular structure and device performance.We hope this review can inspire further innovative development of HTMs for wide applications in highly efcient and stable inverted PVSCs and the tandem devices.