8-羟基喹啉铝作为修饰层对C60有机场效应管性能影响的研究

采用真空蒸镀技术制备了以喹啉铝(tris(8-hydroxyquinoline) aluminum, Alq3)作为修饰层的C60有机场效应管器件,并研究了修饰层的厚度对于器件性能的影响。实验表明,随着Alq3修饰层厚度的增加,器件的性能参数得到改进。当Alq3修饰层厚度为10nm时,器件场效应的迁移率达到最大值,为1.2810-2cm2/Vs,阈值电压也下降到了10V。分析了缓冲层使器件性能提高的主要原因可能有两个：一个是可以阻止金属原子扩散进入C60有机层,另一个是使Al/C60界面间的沟道电阻降低。     

并五苯钝化层增强C60有机场效应晶体管性能的研究

We investigated the properties of C₆₀-based organic field-enect transistors（OFETs）（?） a pentacene passivation layer inserted between the C₆₀ active layer and the gate dielectric.After modification of the pentacene passivation layer,the performance of the devices was considerably improved compared to C₆₀-based OFETs with only a PMMA dielectric.The peak field-effect mobility was up to 1.01 cm²/（V·s） and the on/off ratio shifted to 10⁴.This result indicates that using a pentacene passivation layer is an effective way to improve the performance of N-type OFETs.     

C60场效应晶体管的制备及修饰层对器件性能影响的研究

以重掺杂Si片作为衬底,SiOe／聚甲基丙烯酸甲酯（PMMA）为双栅绝缘层,C60为有源层,制备了不同修饰层的有机场效应晶体管（OFETs）;研究了不同修饰层的器件对于场效应性能的影响。实验表明,与未加修饰层的器件相比,经过修饰的器件性能有一定的提高,其中Alqa／LiF双修饰层器件的场效应迁移率达到最大,为1．6×1...     

Enhanced performance of PbPc photosensitive organic field effect transistors by inserting different-thickness pentacene inducing layers

Lead phthalocyanine (PbPc) based photosensitive organic field effect transistors (PhOFETs) with different-thickness pentacene inducing layers (INLs) inserted between SiO₂ and PbPc layer were fabricated and characterized. The photoelectric measurements demonstrate that the device with 2-nm-thick pentacene INL exhibits the largest photoresponsivity of 505.75 mA/W and maximum photo/dark current ratio of 405.35 in all devices. For this, we give an overall explanation that different-thickness INLs display different continuity and crystallinity and thus produce strong or weak template inducing. Especially, when the INL thickness (δ) is 2 nm a quasi-continuous and highly crystalline approximate-monolayer INL forms on SiO₂ surface, which may play a strong role of template inducing, thus causing its upper PbPc film to demonstrate the strongest triclinic (3 0 0) line and the strongest NIR absorption in series PbPc films. When δ = 1 nm, pentacene does not form a continuous film. And when δ = 5 or 10 nm, a continuous multilayer INL with a declined crystallinity due to possible lattice mismatch forms on SiO₂ surface and gives a weakened template inducing. Thereby, it can be recognized that inserting a pentacene INL can markedly enhance the performance of single layer PbPc PhOFET and the optimum INL thickness is proved ∼2 nm in present conditions.     

Performance improvement mechanisms of pentacene-based organic thin-film transistors using TPD buffer layer

To improve the performances of pentacene-based organic thin-film transistors (OTFTs), a TPD buffer layer was inserted between the Au metal electrode and the pentacene channel layer. As shown by the ultraviolet photoelectron spectroscopy measurement, the Au work function was increased from 4.61 eV for Au in direct contact with pentacene to 4.74 eV and 4.78 eV for the sample inserted with 2-nm-thick and 3-nm-thick TPD buffer layers, respectively, between the Au metal electrode and the pentacene channel layer. Moreover, the contact resistance was reduced from 1 MΩ to 0.1 MΩ by inserting a 2-nm-thick TPD buffer layer. Compared with the transconductance of 2.67 × 10^?7 S, the field-effect mobility of 0.46 cm²/V s, and the substhreshold swing of 1.78 V/decade for the conventional pentacene-based OTFTs without TPD buffer layer, the transconductance, the field-effect mobility, and the subthreshold swing were improved to 9.77 × 10^?7 S, 1.68 cm²/V s, and 1.46 V/decade, respectively, for the pentacene-based OTFTs inserted with a 2-nm-thick TPD buffer layer. By considering the trade-off between the increase of Au work function and the tunneling effect, the optimal thickness of the TPD buffer layer in the pentacene-based OTFTs was 2 nm.     

基于插入WO3缓冲层并五苯有机场效应晶体管性能的研究

The pentacene-based organic field effect transistor （OFET） with a thin transition metal oxide （WO3） layer between pentacene and metal （AI） source/drain electrodes was fabricated. Compared with conventional OFET with only metal AI source/drain electrodes, the introduction of the WO3 buffer layer leads to the device performance enhancement. The effective field-effect mobility and threshold voltage are improved to 1.90 em2/（V.s） and 13 V, respectively. The performance improvements are attributed to the decrease of the interface energy barrier and the contact resistance. The results indicate that it is an effective approach to improve the OFET performance by using a WO3 buffer layer.     

利用MoO3为电极修饰层的F16CuPc/ CuPc异质结的双极性有机场效应晶体管

在本文中,我们利用钛青铜(CuPc)和氟化钛青铜(F16CuPc)作为空穴传输层和电子传输层的制备了具有异质结结构的有机场效应晶体管(OFETs)。与单层的F16CuPc晶体管相比,异质结结构的晶体管的电子迁移率从3.1×10-3cm2/Vs提高至8.7×10-3cm2/vs,然而,空穴的传输行为却没有被观测到。为了提高空穴的注入能力,我们利用MoO3对源-漏电极进行了修饰,有效地改善了空穴注入。并进一步证实了MoO3的引入使得器件的接触电阻变小,平衡了电子和空穴的注入,从而最终实现了器件的双极性传输。     

基于Re-BCP为缓冲层有机太阳能电池性能的研究

有机太阳能电池(OSCs)因成本低、质量轻、柔性 和可大面积制备等优点而被广泛关注。本文通过定向合成有机配合物Re-BCP,首次将其作 为阴极缓冲层引入到OSCs中。通过实验发现,OSCs效率与Re-BCP层厚度密切相关。在标准 太阳光照条件下,结构为ITO/CuPc(20nm)/C60(40nm)/Re-BCP(x nm)/Al(100nm)器件的效率随着Re-BCP厚度的增加先增大后变 小,当其厚为0nm时,效率为0.65%;厚为7nm时,效率为1.10%;而当厚为10nm时,效率降为0.50%。结合器件结构,探讨了器件性能提高的机理。     

Comparison of modulation doped effect in negative differential resistance field effect transistors (NDRFETs)

N-shaped negative differential resistance field effect transistors (NDRFETs) have been fabricated and demonstrated. The interesting N-shaped NDRs are three terminal controlled phenomena. This N-shaped NDR behavior is found in the higher drain-to-source voltage (V_DS) regime and is obtained both at positive and negative gate-to-source bias (V_GS). We believe that the NDR phenomena are attributed to the real space transfer (RST) effect. Due to the modulation doped effect and different barrier height, the NDR behavior can easily be controlled. The influence of V_GS bias on the NDR characteristics is also investigated.     

C_(60)作激子阻挡层的有机发光二极管

制备了结构为ITO/CuPc(25nm)/NPB(40nm)/Alq3(xnm)/C60(ynm)/LiF(1nm)/Al(100nm)的有机发光二极管(OLEDs),研究了C60插入层对器件性能的影响。结果表明,在无C60的器件中,当Alq3层较厚时,器件的电流密度-电压(J-V)曲线右移,不利于获得高功率效率;当Alq3层较薄时,又会导致激子在LiF/Al阴极的严重淬灭。实验优化得出,在无C60的器件中,Alq3厚为45nm的器件可获得最高的功率效率。在Alq3与LiF之间插入15nmC60层后,对器件的J-V曲线几乎没有影响,但C60层阻挡了激子向阴极扩散,减少了淬灭。当在Alq3厚度为45nm的器件的Alq3和LiF间插入15nmC60层后,可使器件获得更高的功率效率,尤其是插入15nmC并将Alq厚度降至30nm,获得了最大的功率效率。     

Enhanced performance of inverted perovskite solar cells using solution-processed carboxylic potassium salt as cathode buffer layer

Using a novel solution-processed carboxylic potassium salt (F-R-COOK) as cathode buffer layer (CBL), a power conversion efficiency (PCE) of 14.37% is obtained, which is more than 51% increase compared with that of the Ag-only device under similar fabrication conditions. The test result of single electron devices and Electrochemical impedance spectroscopy (EIS) measurements demonstrate that the interlayer decreases charge transport resistance. Ultraviolet photoelectron spectroscopy (UPS) measurements are used to study the interfacial effects induced by the new CBL. It is found that F-R-COOK can reduce the work function of the Ag electrode by forming desired interfacial dipoles. Our work indicates the promising applications of F-R-COOK based CBL in perovskite solar cells and may provide some insights into the design and synthesis of new interfacial materials to further improve the device performance.     

基于CuBB为阴极缓冲层有机太阳能电池性能的研究

通过定向合成Cu(I)配合物,首次将 其作为阴极缓冲层引入到有机太阳能电池(OSCs)中。实验分析发现,OSCs的光电能量转换效 率(PCE)与CuBB层厚度紧密相关,在标准太阳 光照条件下,结构为ITO/CuPc (20nm)/C60(40nm)/CuBB (x m m)/Al (100nm)的器件PCE随着CuBB厚度的增加 先增大后变小,当厚为8nm 时PCE达到0.94%。器件性能提高的原因主要是CuBB具有良好 的电子迁移率,但厚度过大时则由于串联电阻增加及电子不能经阴极缓冲层传输而使性能降 低。     

Bathocuproine作为缓冲层改善Rubrene/C70太阳能电池的性能

制备了结构为ITO/Rubrene/C70/BCP/Al的双层有机太阳能电池(OSCs),通过优化缓冲层BCP的厚度研究了BCP对OSCs性能的影响及其作用机理。实验发现,BCP厚为6nm时,器件的效率最高达到1.78%,同时获得了较大的开路电压0.901V。相对于没有缓冲层,器件的效率、短路电流、开路电压和填充因子分别提高了432.9%、74.8%、95.4%和55.5%。     

Color switching behaviors of organic bistable light-emitting devices fabricated utilizing an aluminum-nanoparticle-embedded tris(8-hydroxyquinoline)aluminum layer and double emitting layers

Organic bistable light-emitting devices (OBLEDs) with an aluminum (Al)-nanoparticle-embedded tris(8-hydroxyquinoline)aluminum (Alq₃) layer and double emitting layers (EMLs) were fabricated to investigate their color switching behaviors. Scanning electron microscopy images showed that Al nanoparticles were formed on the Alq₃ layer. The Al nanoparticles in the Alq₃ layer improved the storage margin of the organic bistable devices (OBDs), and the double EMLs changed the emission color of the organic light-emitting devices (OLEDs) according to the variations of the ON and the OFF states of the OBDs. The variations of the ON and the OFF states of the OBDs could be clearly distinguished by the color switching of the OLED. The luminances of the OBLEDs with double EMLs in the ON and the OFF states were 641.80 and 22.25 cd/m², respectively, and their CIE coordinates at 20 V were (0.42, 0.46) and (0.51, 0.47), respectively, which corresponded to the ON and the OFF states of the OBLEDs.     

Fast detection of blood gases by solution gated organic field effect transistors

We characterize the electrochemical stability of the organic semiconductor Dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) in aqueous solutions. Electrochemical stability of DNTT in solution is validated by cyclic voltammetry and demonstrated by solution gating of DNTT organic field effect transistors (OFETs). Then, we investigate the response time of DNTT OFETs to ammonia, a common blood gas. For bare OFETs, the response time to ammonia is 1–2s only. The exact response time depends on the DNTT film morphology; the fastest response is obtained for pronounced 3D (Volmer-Weber) growth. By comparing OFETs with and without a semipermeable parylene-C encapsulation layer, the influence of the capping on the response time is investigated. An encapsulation layer of 86 nm prolongs the response time to 100s, indicating that parylene-C acts as an efficient diffusion barrier for ammonia.     

双阴极修饰层改善Rubrene/C70有机太阳能电池的性能

采用NTCDA/PTCBI双阴极修饰层制备了结构为ITO /MoO₃/Rubrene/C70/NTCDA/PTCBI/Al有机太阳能 电池(OSC),研究了双阴极修饰层对Rubrene/C70 OSC性能的影 响。实验结果表明,引入双阴极修饰层 后,器件的各性能参数有了显著提高。通过对PTCBI厚度优化发现,当PTCBI厚为5nm时器件 的各性 能参数最佳,器件的功率转换效率(PCE)=3.19%,电流密度Jsc=8.99mA·cm－2,开路电 压Voc=0.85V, 填充因子(FF)=41.58%,与未插入PTCBI 层相比器件的各性能分别提高了538%、338.5% 、13.3%和16.5%。     

Bottom-contact small-molecule n-type organic field effect transistors achieved via simultaneous modification of electrode and dielectric surfaces

Low-voltage, n-type organic field effect transistors (OFETs) with simultaneously modified bottom-contact (BC) electrodes and dielectric were compared to their top-contact (TC) counterparts. The devices modified with 6-phenoxyhexylphosphonic acid (Ph6PA) self-assembled monolayer (SAM) showed similar performance, morphology, and contact resistance. Electron mobility of C₆₀ devices were 0.212 and 0.320 cm² V⁻¹ s⁻¹ and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) devices were 0.04 and 0.06 cm² V⁻¹ s⁻¹ for TC and BC devices, respectively. Low contact resistance between 11 and 45 kΩ cm was found regardless of device architecture or n-type semiconductor used. This work shows it is possible to fabricate solution processable low-voltage bottom-contact devices with performance that is similar or better than their top-contact counterparts without the addition of complex and time-consuming processing steps.     

Air stable C60 based n-type organic field effect transistor using a perfluoropolymer insulator

Air stable n-type organic field effect transistors (OFETs) based on C₆₀ are realized using a perfluoropolymer as the gate dielectric layer. The devices showed the field-effect mobility of 0.049 cm²/V s in ambient air. Replacing the gate dielectric material by SiO₂ resulted in no transistor action in ambient air. Perfluorinated gate dielectric layer reduces interface traps significantly for the n-type semiconductor even in air.     

Nonvolatile memory and opto-electrical characteristics of organic memory devices with zinc oxide nanoparticles embedded in the tris(8-hydroxyquinolinato)aluminum light-emitting layer

The nonvolatile organic memory devices based on the tris(8-hydroxyquinolinato)aluminum (Alq₃) emitting layer embedded with zinc oxide nanoparticles (ZnO-NPs) are reported. The devices have a typical tri-layer structure consisting of the Alq₃/ZnO-NPs/Alq₃ layers interposed between indium tin oxide (ITO) and aluminum (Al) electrodes. An external bias is used to program the ON and OFF states of the device that are separated by a four-orders-of-magnitude difference in conductivity. No significant degradation of the device is observed in either the ON or OFF state after continuous stress (∼10⁵ s) and multicycle (∼10³ cycles) testings. These nanoparticles behave as the charge trapping units, which enable the nonvolatile electrical bistability when biased to a sufficiently high voltage. Impedance spectroscopy, capacitance–voltage (C–V) and current–voltage (I–V) analysis are used to verify the possible physical mechanism of the switching operation. Moreover, it is found that the location of the ZnO-NPs could affect the memory and opto-electrical characteristics of the devices, such as the ON/OFF ratio, threshold voltage and turn-on voltage, which can be attributed to the influence of the ZnO-NPs and diffused Al atoms in the bulk of the Alq₃ layer.