7180 wileyonlinelibrary.com IntroductionIn the past decade amorphous metaloxide thin-fi lm transistors (TFTs) have been studied in depth for applications in active-matrix organic light-emitting diodes (AMOLEDs), solar cells, biosensor arrays, and photodetectors. [ 1 ] Along with the rapid developments in display technology, highresolution and high-speed displays have become one of the growing trends. In this regard, energy consumption has turned out to be an inevitable issue especially for mobile, battery-powered applications. As a low-voltage operation of the oxide TFTs is demanded for practical applications, it is necessary to develop novel gate dielectrics for producing a large areal capacitance. [ 2 ] The achievements of low-voltage oxide TFTs have been extensively reported in recent works, including the use of inorganic high-k dielectrics, [ 3 ] organic self-assembled-monolayer dielectrics, [ 4 ] and electrolyte dielectrics. [ 5 ] Among these, the use of inorganic high-k dielectrics is the most attractive option as it simultaneously enables a low leakage current, through the use of a thicker fi lm, as well as a low-voltage operation. The high-k dielectrics can be prepared by various methods such as metal anodic oxidation method, [ 6 ] vacuum-based deposition, [ 7 ] and low-cost solution-based techniques. [ 8 ] [ 12 ] silicates, [ 13 ] etc.) that could potentially replace conventional dielectrics, such as SiO 2 and SiN x . To the best of our knowledge, there are few reports on the demonstration of scandium oxide (Sc 2 O 3 ) as the gate dielectric in TFT devices.As a high-k material Sc 2 O 3 has a dielectric constant of 14, a bandgap of 6.3 eV and an excellent thermal stability with Si. [ 14 ] In addition, Sc 2 O 3 has been found to possess a negative fi xed charge. This is benefi cial to obtain a positive threshold or turnon voltage for n-type TFTs that operate in the enhancement mode. [ 15 ] Concerning the CMOS architecture development based on solution processing, a wet step is inevitably involved. In this regard, the resistance to moisture absorption is another important , a large current ratio ( I on / I off ) of 2.7 × 10 7 and high stability. Moreover, as far as we know it is the fi rst time that solution-processed p-type oxide TFTs based on a high-k dielectric are achieved. The as-fabricated p-type CuO/ScO x TFTs exhibit a large I on / I off of around 10 5 and a hole mobility of 0.8 cm 2 V −1 at an operating voltage of 3 V. To the best of our knowledge, these electrical parameters are among the highest performances for solution-processed p-type TFTs, which represents a great step towards the achievement of low-cost, all-oxide, and low-power consumption CMOS logics.

In this study, indium oxide (In2O3) thin-film transistors (TFTs) were fabricated by a fully-solution process at low temperature.

Electrocatalytic water-splitting catalysts play important roles in clean energy conversion systems. Herein, metal–organic framework-derived (MOF-derived) hollow CoS x @MoS2 microcubes were successfully synthesized by a novel method. Co-MOF [(CH3)2NH2]­[Co­(HCOO)3] prepared by a simple liquid precipitation method at room temperature reacted with S2– released from thioacetamide (TAA) to generate Co9S8 under solvothermal conditions. Through hydrothermal treatment, numerous MoS2 nanosheets grew on the surface of CoS x vertically and uniformly after introduction of sulfur and molybdenum sources, finally generating CoS x @MoS2 heterostructures. As bifunctional electrocatalysts, the heterostructures exhibited remarkable performance for the hydrogen evolution reaction with a low overpotential of 239 mV when the current density increased up to 10 mA cm–2 and a small Tafel slope of 103 mV dec–1 in 0.5 M H2SO4. They also worked effectively for the oxygen evolution reaction with a low overpotential of 347 mV at 10 mA cm–2 in 1 M KOH. The enhanced electrocatalytic activities of CoS x @MoS2 can be ascribed to their unique heterostructures and the synergism between CoS x and MoS2.

No abstract