Thin film transistors (TFTs) with amorphous zinc tin oxide (ZTO) channel layer were fabricated by a simple and low-cost solution process. The ZTO thin films are highly transparent (>90% transmittance) in the visible region. The ZTO TFTs fabricated at 400 and 500 • C are operated in enhancement mode. The TFT annealed at 500 • C shows a mobility of 14.11 cm 2 V −1 s −1 , a threshold voltage of 1.71 V, a subthreshold slope of 0.4 V dec −1 and an on-off current ratio greater than 10 8. In addition, we investigated the gate bias stability of the TFT. Positive gate bias results in a positive shift of the threshold voltage due to the charge trapping in the channel/dielectric interface.

A transparent paper made of chitin nanofibers (ChNF) is introduced and its utilization as a substrate for flexible organic light-emitting diodes is demonstrated. Given its promising macroscopic properties, biofriendly characteristics, and availability of the raw material, the utilization of the ChNF transparent paper as a structural platform for flexible green electronics is envisaged.

Transparent electrodes that can maintain their electrical and optical properties stably against large mechanical deformations are essential in numerous applications of flexible and wearable electronics. In this paper, we report a comprehensive analysis of the electrical, optical, and mechanical properties of hybrid nanostructures based on graphene and metal nanotrough networks as stretchable and transparent electrodes. Compared to the single material of graphene or the nanotrough, the formation of this hybrid can improve the uniformity of sheet resistance significantly, that is, a very low sheet resistance (1 Ω/sq) with a standard deviation of less than ±0.1 Ω/sq, high transparency (91% in the visible light regime), and superb stretchability (80% in tensile strain). The successful demonstration of skin-attachable, flexible, and transparent arrays of oxide semiconductor transistors fabricated using hybrid electrodes suggests substantial promise for the next generation of electronic devices.

We report a flexible high-performance conducting film using an embedded copper nanowire transparent conducting electrode; this material can be used as a transparent electrode platform for typical flexible optoelectronic devices. The monolithic composite structure of our transparent conducting film enables simultaneously an outstanding oxidation stability of the copper nanowire network (14 d at 80 °C), an exceptionally smooth surface topography (R(rms) < 2 nm), and an excellent opto-electrical performances (Rsh = 25 Ω sq(-1) and T = 82%). A flexible organic light emitting diode device is fabricated on the transparent conducting film to demonstrate its potential as a flexible copper nanowire electrode platform.

Transparent flexible fluorine-doped indium zinc oxide (IZO:F) thin-film transistors (TFTs) were demonstrated using the spin-coating method of the metal fluoride precursor aqueous solution with annealing at 200°C for 2 hrs on polyethylene naphthalate films. The proposed thermal evolution mechanism of metal fluoride aqueous precursor solution examined by thermogravimetric analysis and Raman spectroscopy can easily explain oxide formation. The chemical composition analysed by XPS confirms that the fluorine was doped in the thin films annealed below 250°C. In the IZO:F thin films, a doped fluorine atom substitutes for an oxygen atom generating a free electron or occupies an oxygen vacancy site eliminating an electron trap site. These dual roles of the doped fluorine can enhance the mobility and improve the gate bias stability of the TFTs. Therefore, the transparent flexible IZO:F TFT shows a high mobility of up to 4.1 cm2/V·s and stable characteristics under the various gate bias and temperature stresses.

Transparent thin-film transistors ͑TTFTs͒ with an indium-zinc oxide ͑IZO͒ active layer by the solution-processed deposition method were fabricated and their TFT characterization was examined. Solution-processed IZO thin films were amorphous and highly transparent with Ͼ90% transmittance in the visible region with an optical bandgap of 3.1 eV. Spin-coated IZO TTFTs were operated in depletion mode and showed a field-effect mobility as high as 7.3 cm 2 /V s, a threshold voltage of 2.5 V, an on/off current ratio greater than 10 7 , and a subthreshold slope of 1.47 V/decade. Metal-oxide thin films have been traditionally used as insulators, dielectrics, and conductors in ͑opto͒electronic devices. Recently, metal-oxide thin films have been intensively studied to be applied as transparent semiconducting active layers in transparent thin-film transistors ͑TTFTs͒. Transparent oxide semiconductors ͑TOSs͒ have many advantages compared to silicon or organic semiconductors. TOSs are transparent in the visible region due to their large bandgap and have environmental stability and high field-effect mobility comparable to that of polycrystalline silicon. 1,2 Many TOSs such as ZnO, 3,4 zinc-tin oxide ͑ZTO͒, 5,6 indium-zinc oxide ͑IZO͒, 7-9 and indium-gallium-zinc oxide ͑IGZO͒ 2,10,11 have been reported for transparent active-channel materials in TTFTs. Several TTFTs using TOSs 12,13 and even fully transparent flexible structures 3,14 have been reported. TTFTs based on TOSs are considered to be an alternative to amorphous Si TFTs. However, TOSs are generally prepared by vacuum-deposition methods such as rf magnetron sputtering and pulsed laser deposition. Vacuum-deposition methods require expensive equipment and result in high manufacturing costs.Solution-processed thin-film deposition methods could offer many advantages such as simplicity, low cost, and high throughput that enable the fabrication of high-performance and low-cost electronics. In addition, solution-processed deposition methods such as screen printing, inkjet printing, and imprinting offer the possibility of the direct patternability of TOS thin films which could replace the conventional photolithographic technique. Recently, ZnO, 15-17 ZTO, 18 and IZO-based 19 TTFTs fabricated by solution-processed deposition using metallorganic or metal halide precursors in various solvents were reported to have high mobility up to ϳ16 cm 2 /V s and to give direct patternability. However, in the case of using metal chloride as precursors, the presence of chloride ions during heattreatment of the film is unfavorable under certain circumstances. In addition, TTFTs fabricated by solution-processed deposition showed high off currents and a low on/off current ratio compared to the vacuum-deposited TTFTs.In this article, we report the amorphous IZO semiconductor thin films fabricated by solution process under ambient air conditions using metal acetates as precursors and the performance of TTFTs with an amorphous IZO active layer. Spin-coated IZO thin film was uniform, highly transparent...

Recent advances in smart contact lenses are essential to the realization of medical applications and vision imaging for augmented reality through wireless communication systems. However, previous research on smart contact lenses has been driven by a wired system or wireless power transfer with temporal and spatial restrictions, which can limit their continuous use and require energy storage devices. Also, the rigidity, heat, and large sizes of conventional batteries are not suitable for the soft, smart contact lens. Here, we describe a human pilot trial of a soft, smart contact lens with a wirelessly rechargeable, solid-state supercapacitor for continuous operation. After printing the supercapacitor, all device components (antenna, rectifier, and light-emitting diode) are fully integrated with stretchable structures for this soft lens without obstructing vision. The good reliability against thermal and electromagnetic radiations and the results of the in vivo tests provide the substantial promise of future smart contact lenses.

Nonhydrolytic sol-gel condensation for the synthesis of nanosized inorganic-organic hybrid resin and hydrosilylation reaction under a Pt catalyst for the fabrication of oligosiloxane-based hybrid material (phenyl hybrimer) were used in this research. This combination of two chemical reactions results in material with useful properties for light emitting diode (LED) encapsulation. Until now, no polymers and phenyl polysiloxane materials have been reported with a high refractive index (over 1.52) and high transparency accompanied by resistance to yellowing induced by thermal degradation above 150 °C aging in air. In this article, we focused on the fabrication of a transparent and thermally stable phenyl hybrimer with high refractive index for LED encapsulation through siloxane networking by a hydrosilylation reaction with cross-linker and Pt caltalyst. The phenyl hybrimer has a high refractive index about 1.56. In particular, it has good thermal stability against discoloration to yellow by aging even at 200 °C, which is a key factor for the long lifetime of a LED encapsulant.