共查询到12条相似文献,搜索用时 7 毫秒
1.
Dhinesh Babu Velusamy Richard Hahnkee Kim Kazuto Takaishi Tsuyoshi Muto Daisuke Hashizume Soyoon Lee Masanobu Uchiyama Tetsuya Aoyama Jean-Charles Ribierre Cheolmin Park 《Organic Electronics》2014,15(11):2719-2727
Polymer ferroelectric-gate field effect transistors (Fe-FETs) employing ferroelectric polymer thin films as gate insulators are highly attractive as a next-generation non-volatile memory. For minimizing gate leakage current of a device which arises from electrically defective ferroelectric polymer layer in particular at low operation voltage, the materials design of interlayers between the ferroelectric insulator and gate electrode is essential. Here, we introduce a new solution-processed interlayer of conductive reduced graphene oxides (rGOs) modified with a conjugated block copolymer, poly(styrene-block-paraphenylene) (PS-b-PPP). A FeFET with a solution-processed p-type oligomeric semiconducting channel and ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) insulator exhibited characteristic source–drain current hysteresis arising from ferroelectric polarization switching of a PVDF-TrFE insulator. Our PS-b-PPP modified rGOs (PMrGOs) with conductive moieties embedded in insulating polymer matrix not only significantly reduced the gate leakage current but also efficiently lowered operation voltage of the device. In consequence, the device showed large memory gate voltage window and high ON/OFF source–drain current ratio with excellent data retention and read/write cycle endurance. Furthermore, our PMrGOs interlayers were successfully employed to FeFETs fabricated on mechanically flexible substrates with promising non-volatile memory performance under repetitive bending deformation. 相似文献
2.
In this report, we have demonstrated the optical non-volatile memory characteristics using CuPc OFET. The memory operation was comprehensively demonstrated with different programming conditions. It was found that the programming of CuPc OFET with an electric pulse at the gate terminal under UV-light photo-illumination compared to other programming conditions, could substantially increase the memory window due to massive charge trapping in the polymer electret layer, which causes shift in the device transfer characteristics from low-conduction state (“OFF state”, or logic 0) to high conduction state (“ON state”, or logic 1) at VGS = 0V. From device operation at −50V, a memory window of greater than 45V could be achieved by applying a programming voltage of +70 V at the gate terminal under UV-light photo-illumination. Moreover, it was completely erased by applying −100 V at the gate terminal in dark. 相似文献
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The concept of using printed inorganic/organic hybrid distributed Bragg reflectors (DBRs) utilizing inorganic semiconductor and insulating polymers in microcavity polymer electroluminescent devices is introduced to provide an approach to achieve the spectral narrowing and the strong forward directionality. The large refractive index contrast of approximately 0.5 (0.44) between inorganic copper(I) thiocyanate, CuSCN, and insulating polymer of poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE) (cellulose acetate, CA) results in the fabrication of solution-processed inorganic-organic hybrid dielectric DBRs with high reflectivity (>90%) from nanostructures consisting of only four (five) bilayers. For DBRs composed of CuSCN/CA alternative dielectric layers, all-solution processed microcavity polymer light-emitting diode based on highly conductive poly(ethylenedioxythiophene):poly(styrenesulfonate) anode except for Ag cathode exhibits the narrowing of EL spectrum with a full width at half maximum of approximately 25 nm and the maximum luminance of above 10,000 cd/m2. From the viewpoint of dielectric DBRs based on ferroelectric polymer P(VDF-TrFE) with both low refractivity and high permittivity, we demonstrate a microcavity AC voltage-driven polymer electroluminescent device (μcACEL) which exhibits the spectral narrowing and the strong forward directionality. This work is anticipated to be useful for the development of solution-processed μcACEL with unique device architecture. 相似文献
5.
L. Sardone C. C. Williams H. L. Anderson G. Marletta F. Cacialli P. Samorì 《Advanced functional materials》2007,17(6):927-932
Scanning force microscopy (SFM) is used to study the surface morphology of spin‐coated thin films of the ion‐transport polymer poly(ethylene oxide) (PEO) blended with either cyclodextrin (CD)‐threaded conjugated polyrotaxanes based on poly(4,4′‐diphenylene‐vinylene) (PDV), β‐CD–PDV, or their uninsulated PDV analogues. Both the polyrotaxanes and their blends with PEO are of interest as active materials in light‐emitting devices. The SFM analysis of the blended films supported on mica and on indium tin oxide (ITO) reveals in both cases a morphology that reflects the substrate topography on the (sub‐)micrometer scale and is characterized by an absence of the surface structure that is usually associated with phase segregation. This observation confirms a good miscibility of the two hydrophilic components, when deposited by using spin‐coating, as suggested by the luminescence data on devices and thin films. Clear evidence of phase segregation is instead found when blending PEO with a new organic‐soluble conjugated polymer such as a silylated poly(fluorene)‐alt‐poly(para‐phenylene) based polyrotaxane (THS–β‐CD–PF–PPP). The results obtained are relevant to the understanding of the factors influencing the interfacial and the intermolecular interactions with a view to optimizing the performance of light‐emitting diodes, and light‐emitting electrochemical cells based on supramolecularly engineered organic polymers. 相似文献
6.
采用聚氧化乙烯(PEO)作为聚合物太阳能电池的阴极修饰层,以P3HT:PCBM为活性层制备了聚合物本体异质结太阳能电池。考察了PEO的厚度对器件光伏性能及稳定性的影响。比较了加入PEO修饰层前后器件的稳定性,研究了采用PEO修饰层前后器件电阻的差异。结果表明:加入PEO作为阴极修饰层后器件的光电性能(JSC,VOC,FF,PCE)均有明显提高,而器件的串联电阻Rs则有了明显降低。没有阴极修饰层的器件的初始光电转换效率为1.92%,90 h后衰减为初始值的5%;而加入PEO修饰层后初始光电转换效率为3.36%,90 h后仅衰减为初始值的20%,光电转换效率提高了75%,稳定性提高了3倍。 相似文献
7.
G. Niu S. YinG. Saint-Girons B. GautierP. Lecoeur V. PillardG. Hollinger B. Vilquin 《Microelectronic Engineering》2011,88(7):1232-1235
In this study we report the epitaxial growth of BaTiO3 films on Si(0 0 1) substrate buffered by 5 nm-thick SrTiO3 layer using both MBE and PLD techniques. The BaTiO3 films demonstrate single crystalline, (0 0 1)-oriented texture and atomically flat surface on SrTiO3/Si template. The electrical characterizations of the BaTiO3 films using MFIS structures show that samples grown by MBE with limited oxygen pressure during the growth exhibit typical dielectric behavior despite post deposition annealing process employed. A ferroelectric BaTiO3 layer is obtained using PLD method, which permits much higher oxygen pressure. The C-V curve shows a memory window of 0.75 V which thus enable BaTiO3 possibly being applied to the non-volatile memory application. 相似文献
8.
Ashok Kumar M. R. Alam A. Mangiaracina M. Shamsuzzoha 《Journal of Electronic Materials》1997,26(11):1331-1334
Ferroelectric lead-zirconate-titanate (PZT) thin films were deposited by the pulsed laser deposition technique on Pt-coated
(100) Si substrates. This study was focused on the investigation of the PZT film growth on (100) Si substrate at varying deposition
parameters and electrical characterization of the films including hysteresis loop and fatigue properties by RT66A Standardized
Ferroelectric Test System. PZT deposited at higher temperature (575°C in 450 mTorr O2 partial pressure) showed the best crystalline structure. The remnant polarization and the retained polarization of the ferroelectric
capacitors were 13 μC/cm2 and 20 μC/cm2, respectively. The crystallographic properties of the films were determined using the x-ray diffractometer method. The cross-sectional
transmission electron microscope results showed very smooth interfaces among different layers of films. 相似文献
9.
La-modified lead titanate (PLT) thin films were prepared by hot-wall type low pressure-metalorganic chemical vapor deposition
method. Pb(dpm)2, La(dpm)3, and titanium tetraisopropoxide were used as source materials. The films were deposited at 500°C under the low pressure of
1000 mTorr and then annealed at 650°C for 10 min in oxygen ambient. Sputter-deposited platinum electrodes and 180 nm thick
PLT thin films were employed to form MIM capacitors with the best combination of high charge storage density (26.7 μC/cm2 at 3V) and low leakage current density (1.5 × 10-7 A/cm2 at 3V). The measured dielectric constant and dielectric loss were 1000∼1200 and 0.06∼0.07 at zero bias and 100 kHz, respectively. 相似文献
10.
All‐Inorganic CsPbI3 Perovskite Phase‐Stabilized by Poly(ethylene oxide) for Red‐Light‐Emitting Diodes
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Beomjin Jeong Hyowon Han Yung Ji Choi Sung Hwan Cho Eui Hyuk Kim Seung Won Lee Jong Sung Kim Chanho Park Dongho Kim Cheolmin Park 《Advanced functional materials》2018,28(16)
Despite the excellent photoelectronic properties of the all‐inorganic cesium lead iodide (CsPbI3) perovskite, which does not contain volatile and hygroscopic organic components, only a few CsPbI3 devices are developed mainly owing to the frequent formation of an undesirable yellow δ‐phase at room temperature. Herein, it is demonstrated that a small quantity of poly(ethylene oxide) (PEO) added to the precursor solution effectively inhibits the formation of the yellow δ‐phase during film preparation, and promotes the development of a black α‐phase at a low crystallization temperature. A systematic study reveals that a thin, dense, pinhole‐free CsPbI3 film is produced in the α‐phase and is stabilized with PEO that effectively reduces the grain size during crystallization. A thin α‐phase CsPbI3 film with excellent photoluminescence is successfully employed in a light‐emitting diode with an inverted configuration of glass substrate/indium tin oxide/zinc oxide/poly(ethyleneimine)/α‐CsPbI3/poly(4‐butylphenyl‐diphenyl‐amine)/WO3/Al, yielding the characteristic red emission of the perovskite film at 695 nm with brightness, external quantum efficiency, and emission band width of ≈101 cd m?2, 1.12%, and 32 nm, respectively. 相似文献
11.
Light‐Emitting Diodes: All‐Inorganic CsPbI3 Perovskite Phase‐Stabilized by Poly(ethylene oxide) for Red‐Light‐Emitting Diodes (Adv. Funct. Mater. 16/2018)
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Beomjin Jeong Hyowon Han Yung Ji Choi Sung Hwan Cho Eui Hyuk Kim Seung Won Lee Jong Sung Kim Chanho Park Dongho Kim Cheolmin Park 《Advanced functional materials》2018,28(16)
12.
The electrical and optical properties of certain semiconducting polymers are improved in blend films with inert host materials. The improvements have been attributed to the dilution effect of electron traps and interchain species in semiconductor materials. In this paper, we report on anisotropy in the blend films of poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and its strong dependence on an inert host material, such as polystyrene (PS) or polyvinylcarbazole (PVK). We found that the orientation of the MEH-PPV backbone in the blend film changed from horizontal to random on dilution with PS. Moreover, the in-plane hole conductivity was enhanced in the MEH-PPV:PVK blend film, although the out-of-plane conductivity reduced owing to excessive dilution. Mott–Schottky analysis of the capacitance–voltage characteristics revealed opposite trends for dilution with PS and PVK; i.e., PS increased the accumulated charge density in the bulk of the blend film, whereas PVK reduced it. These results demonstrate that isotropy was induced in the PS blend films, whereas anisotropy was induced in the PVK blend films. Anisotropy is an important factor for understanding the hole transport characteristics in the diluted films. 相似文献