Efficient recyclable organic solar cells on cellulose nanocrystal substrates with a conducting polymer top electrode deposited by film-transfer lamination

We report on efficient solar cells on recyclable cellulose nanocrystal (CNC) substrates with a new device structure wherein polyethylenimine-modified Ag is used as the bottom electron-collecting electrode and high-conductivity poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS, PH1000) is used as the semitransparent top hole-collecting electrode. The PEDOT:PSS top electrode is deposited by a film-transfer lamination technique. This dry process avoids swelling damage to the CNC substrate, which is observed when PEDOT:PSS is directly spin-coated from an aqueous solution. Solar cells on recyclable CNC substrates exhibit a maximum power conversion efficiency of 4.0% with a large fill factor of 0.64 ± 0.02 when illuminated through the top semitransparent PEDOT:PSS electrode. The performance of solar cells on CNC substrates is comparable to that of reference solar cells on polyethersulfone substrates.     

新型钝感含能增塑剂3-硝基呋咱-4-甲醚的合成与性能研究

以氰基乙酸乙酯为起始原料,用一锅法先行合成了前体化合物3-氨基呋咱-4-羧酸(AFCA),产率46％.再通过NaBH4/ZnCl2还原体系和H2O2/H2SO4氧化体系先后得到了3-氨基呋咱-4-甲醇(AFMA)及3-硝基呋咱-4-甲醇(NFMA).用SOCl2将NFMA氯化,得到3-硝基-4-氯甲基呋咱(NFCM),...     

Highly reliable hybrid nano-stratified moisture barrier for encapsulating flexible OLEDs

Herein, a novel thin-film encapsulation for flexible organic light-emitting diodes (FOLEDs) is proposed, and its long-term reliability in tensile stress conditions was tested. The hybrid nano-stratified moisture barrier consists of 2.5 dyads of an Al₂O₃/ZnO nano-stratified structure and a S-H nanocomposite organic layer. The nano-stratified structure is prepared by low-temperature atomic layer deposition and the S-H nanocomposite by spin-coating at a thickness of 30 and 120 nm, respectively. An optical transmittance of 89.05% was measured with the 2.5-dyad hybrid nano-stratified moisture barrier with a total thickness of 330 nm. A low water vapor transmission rate (WVTR) of 1.91 × 10⁻⁵ g/m²day was recorded based on an electrical Ca test at 30 °C and 90% R.H. without losing its properties after a bending test. With this highly reliable hybrid nano-stratified moisture barrier, FOLEDs were successfully encapsulated. After 30 days under conditions of 30 °C and 90% R.H. with tensile stress, the J-V-L performances of the FOLEDs were comparable to those of the initial state without dark spots. These results suggest that this hybrid nano-stratified moisture barrier is an excellent method for encapsulating FOLEDs.     

Fabrication and application of silicon-reinforced PDMS masters

A new molding process is developed in this work to generate a silicon (Si)-reinforced polydimethylsiloxane (PDMS) master of a 4 in wafer size using an SU-8 mold. The reinforced PDMS master is applied to pattern a conducting polymer, poly-3-hexylthiophene (P3HT), which is normally dissolved by a non-polar solvent. PDMS is usually patterned by a molding process, in which PDMS is first coated on and then peeled off from a rigid mold. However, in the new molding process, the Si-reinforced PDMS master is rigid but the SU-8 mold is flexible, and the SU-8 mold is first placed on and then peeled off from the rigid PDMS master. In such a way, a reinforced PDMS master of a size as large as a 4 in wafer can be produced. Meanwhile, a new way of obtaining free-standing, large SU-8 structures is presented. PDMS swells when it gets exposed to non-polar solvents. This swelling makes PDMS not suitable for patterning materials, which are usually dissolved by non-polar solvents, e.g., P3HT. In this work, we demonstrate that, with the reinforcement of a Si plate, the swelling effect in generating this specific type of materials is much reduced, and good patterns can be produced.     

器件结构与有机ELD发光效率和寿命

描述了有机EL器件结构设计与其效率和寿命的关系,混合型结构的有机ELD的效率和寿命要比传统异质结构器件高得多。采用阳极buffer layer(如CuPc),阴极buffer layer(如LiF)以及向HTL（空穴传输层）中的染料掺杂也会明显提高效率并增加寿命,比较了不同阴极接触模式,如Al:Li/Alq3,Al/LiF/Alq,Al/LiF:Alq3/Alq3及Al/Li:Alq3/Alq3等对器件效率及寿命影响差异,结果表明,无论哪种阴极接触模式都会提高器件的效率及寿命,而对阳级buffer layer或引入染料掺杂模式,均可以控制或调整空穴的注入,阴极buffer layer是为了增加电子注入,两者目的都是为了防止或减少在发光分子（如Alq3)中被称之为“空穴阳离子”（如[Alq3]^ )的不稳定剂的产生。     

Synthesis of 2,7‐Carbazolenevinylene‐Based Copolymers and Characterization of Their Photovoltaic Properties

New electroactive and photoactive conjugated copolymers consisting of alternating 2,7‐carbazole and oligothiophene moieties linked by vinylene groups have been developed. Different oligothiophene units have been introduced to study the relationship between the polymer structure and the electronic properties. The resulting copolymers are characterized by UV‐vis spectroscopy, size‐exclusion chromatography, and thermal and electrochemical analyses. Bulk heterojunction photovoltaic cells from different copolymers and a soluble fullerene derivative, [6,6]‐phenyl‐C₆₁ butyric acid methyl ester, have been fabricated, and promising preliminary results are obtained. For instance, non‐optimized devices using poly(N‐(4‐octyloxyphenyl)‐2,7‐carbazolenevinylene‐alt‐3″,4″‐dihexyl‐2,2′;5′,2″;5″,2″′;5″′,2″″‐quinquethiophenevinylene 1″,1″‐dioxide) as an absorbing and hole‐carrier semiconductor exhibit power conversion efficiency up to 0.8 % under air mass (AM) 1.5 illumination. These features make 2,7‐carbazolenevinylene‐based and related polymers attractive candidates for solar‐cell applications.     

Fabrication and Characterization of Three‐Dimensional Silver‐Coated Polymeric Microstructures

A method is reported for fabricating complex 3D silver‐coated polymeric microstructures. The approach is based on the creation of a crosslinked polymeric microscaffold via patterned multiphoton‐initiated polymerization followed by surface‐nucleated electroless deposition of silver. The conductivity and reflectivity of the resulting silver–polymer composites and the nanoscale morphology of the deposited silver are characterized. Sub‐micrometer thick layers of silver can be controllably deposited onto surfaces, including those of 3D microporous forms without occluding the interior of the structure. The approach is general for silver coating crosslinked polymeric structures based on acrylate, methacrylate, and epoxide resins and provides a new path to complex 3D micrometer‐scale devices with electronic, photonic, and electromechanical function.     

有机电致发光的效率

描述了评价有机电致发光性能的重要指标－－发光效率问题,从发光机制考虑,一般常用外量子效率和内量子效率来评价。外量子效率是有机电致发光器件输出光子数与注入电子数之比;内量子效率是产生在器件内部的光子数与液入电子数之比,对于光子能否输出到器件外部无关紧要。评价器件性能还有一些其他效率评价方法,如能量效率,功率效率等,特别是外功率效率（1m/W),电流效率（cd/A)也常常用于表征有机电致发光性能,但它们与发光光谱的视觉灵敏度有关,对紫外外辐射器件不适用,另外,利用三重态激子发射可以提高EL器件效率,理论上可达100％,器件结构及材料对器件外量子效率影响至关重要。     

一种新型有机染料HEASPS的激光上转换和光限幅性能

报道了一种新型上转换染料———反式 4 [4’ (N 羟乙基 N 乙基胺基 )苯乙烯基 ] N 甲基吡啶 对甲苯磺酸盐(trans 4 [4’ (N hydroxyethyl N ethylamino)styryl] N methylpyridiniump toluenesulfonate ,简称HEASPS)DMF溶液的激光上转换性质和光限幅性质。用Z 扫描技术测得其双光子吸收截面为σ2 =4.7× 10 -4 8cm4 ·s/photon ,研究了它在DMF溶剂中的线性吸收、单光子荧光、双光子荧光和双光子激射特性 ,用再吸收效应解释了双光子荧光峰相对单光子荧光峰的红移现象 ,该染料的激射和再吸收现象相互竞争导致了双光子激射峰相对于双光子荧光峰的蓝移现象。在 10 6 4nm皮秒脉冲激光的激发下 ,可得强烈的 6 2 6nm上转换激射光 ,上转换效率最高为 15 .5 % ,从抽运光到激射光的净转换效率为 2 6 %。该染料的DMF溶液表现出明显的光限幅特性     

Water-Surface-Mediated Precise Patterning of Organic Single-Crystalline Films via Double-Blade Coating for High-Performance Organic Transistors

Application-oriented growth of patterned organic semiconductor (OSC) thin films with a single domain is a nonnegotiable requirement for the manufacturing of high-performance organic electronic devices. However, the prevalent selective-wetting patterning method remains a challenge in controlling the density of nucleation events in microscale spaces, resulting in thin films with high grain boundary density and no preferential orientation spherulites. Herein, a simple double-blade-coating printing technique using a combination of wetting-patterned substrates to produce an array of highly crystalline OSC thin films is developed. Specifically, the approach confines the OSC crystallization on a molecular-flat water surface in specific areas, enabling a significant reduction in the number of nuclei. Consequently, patterned 2,7-dioctyl[1]benzothieno[3,2-b] benzothiophene (C₈-BTBT) thin films comprising single-crystal domains are achieved with an exceptionally high yield of 62.5%. The organic field-effect transistor array developed from such patterns of C₈-BTBT single-crystalline films exhibits an excellent average mobility of 11.5 cm² V⁻¹ s⁻¹ which is 12.5-fold higher compared to that of the reference sample fabricated via conventional single-blade coating. It is believed that this approach can be widely applied to other soluble organic materials, thereby opening up opportunities for fabricating multicomponent integrated electronics.