No abstract

Hollow, microrod-like Pt nanostructures are locally synthesized on a small, suspended microheater platform (9 μm × 110 μm) as the catalytic layer of a low-power hydrogen (H2) catalytic combustion sensor. The Pt nanostructures are synthesized via two successive Joule heating-assisted chemical reactions. During operation, H2 locally combusts on the surface of the Pt nanostructures and transfers heat to the microheater, which in turn changes its resistance. Because of the highly localized Pt nanostructures and the suspended microheater, the sensor exhibits high sensitivity (ΔR/R 0 ∼ 0.46% per percent of H2), fast response and recovery speeds (<12 s), and low-power consumption (4 mW).

BackgroundRecently, a combination of photodynamic therapy (PDT) and photothermal therapy (PTT) to generate reactive oxygen species (ROS) and heat to kill cancer cells, respectively has attracted considerable attention because it gives synergistic effects on the cancer treatment by utilizing the radiation of nontoxic low-energy photons such as long wavelength visible light and near IR (NIR) penetrating into subcutaneous region. For the effective combination of the phototherapies, various organic photosensitizer-conjugated gold nanocomplexes have been developed, but they have still some disadvantages due to photobleaching and unnecessary energy transfer of the organic photosensitizers.ResultsIn this study, we fabricated novel inorganic phototherapeutic nanocomplexes (Au NR–TiO2 NCs) by conjugating gold nanorods (Au NRs) with defective TiO2 nanoparticle clusters (d-TiO2 NP clusters) and characterized their optical and photothermal properties. They were observed to absorb a broad range of visible light and near IR (NIR) from 500 to 1000 nm, exhibiting the generation of ROS as well as the photothermal effect for the simultaneous application of PDT and PTT. The resultant combination of PDT and PTT treatments of HeLa cells incubated with the nanocomplexes caused a synergistic increase in the cell death compared to the single treatment.ConclusionThe higher efficacy of cell death by the combination of PDT and PTT treatments with the nanocomplexes is likely attributed to the increases of ROS generation from the TiO2 NCs with the aid of local surface plasma resonance (LSPR)-induced hot electrons and heat generation from Au NRs, suggesting that Au NR–TiO2 NCs are promising nanomaterials for the in vivo combinatorial phototherapy of cancer.Electronic supplementary materialThe online version of this article (10.1186/s12951-018-0432-4) contains supplementary material, which is available to authorized users.

Proposed herein is a new technique of activation for the backplane of low-temperature amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs) by applying a bias voltage to gate, source, and drain electrodes and simultaneously annealing them at 150°C. This 'voltage bias activation' can be an effective method of reducing the backplane processing temperature from 300°C to 150°C. Compared with the reference a-IGZO TFTs fabricated at 300°C, the a-IGZO TFTs fabricated through voltage bias activation showed sufficient switching characteristics: 10.39 cm 2 /Vs field effect mobility, 0.41 V/decade subthreshold swing, and 3.65 × 10 7 on/off ratio. These results were analyzed thermodynamically using infrared micro-thermography. In the case of the positive gate voltage bias condition, the maximum temperature of the a-IGZO channel increased to 48°C, and this additional annealing effect and activation energy lowering compensated for the insufficient thermal energy of annealing at a low temperature (150°C). With this approach, a-IGZO TFTs were successfully fabricated at a low temperature. ARTICLE HISTORY

A new technique is proposed for the activation of low temperature amorphous InGaZnO thin film transistor (a-IGZO TFT) backplanes through application of a bias voltage and annealing at 130 °C simultaneously. In this ‘electrical activation’, the effects of annealing under bias are selectively focused in the channel region. Therefore, electrical activation can be an effective method for lower backplane processing temperatures from 280 °C to 130 °C. Devices fabricated with this method exhibit equivalent electrical properties to those of conventionally-fabricated samples. These results are analyzed electrically and thermodynamically using infrared microthermography. Various bias voltages are applied to the gate, source, and drain electrodes while samples are annealed at 130 °C for 1 hour. Without conventional high temperature annealing or electrical activation, current-voltage curves do not show transfer characteristics. However, electrically activated a-IGZO TFTs show superior electrical characteristics, comparable to the reference TFTs annealed at 280 °C for 1 hour. This effect is a result of the lower activation energy, and efficient transfer of electrical and thermal energy to a-IGZO TFTs. With this approach, superior low-temperature a-IGZO TFTs are fabricated successfully.