Flexible a-IGZO phototransistor for instantaneous and cumulative UV-exposure monitoring for skin health

Flexible thin‐film phototransistors based on amorphous indium‐gallium‐zinc‐oxide semiconductor and a novel read‐out scheme allow for both real time and cumulative measurement of the ultraviolet light intensity. Furthermore, encapsulation in polydimethylsiloxane and lamination to human skin, as well as mechanical stability of the device is presented

Recent advances in solid-state organic lasers

Organic solid-state lasers are reviewed, with a special emphasis on works published during the last decade. Referring originally to dyes in solid-state polymeric matrices, organic lasers also include the rich family of organic semiconductors, paced by the rapid development of organic light emitting diodes. Organic lasers are broadly tunable coherent sources are potentially compact, convenient and manufactured at low-costs. In this review, we describe the basic photophysics of the materials used as gain media in organic lasers with a specific look at the distinctive feature of dyes and semiconductors. We also outline the laser architectures used in state-of-the-art organic lasers and the performances of these devices with regard to output power, lifetime, and beam quality. A survey of the recent trends in the field is given, highlighting the latest developments in terms of wavelength coverage, wavelength agility, efficiency and compactness, or towards integrated low-cost sources, with a special focus on the great challenges remaining for achieving direct electrical pumping. Finally, we discuss the very recent demonstration of new kinds of organic lasers based on polaritons or surface plasmons, which open new and very promising routes in the field of organic nanophotonics

A Sustainable Approach to Flexible Electronics with Zinc-Tin Oxide Thin-Film Transistors

Zinc-tin oxide (ZTO) is widely invoked as a promising indium and gallium-free alternative for amorphous oxide semiconductor based thin-film transistors (TFTs). The main bottleneck of this semiconductor material compared to mainstream indium-gallium-zinc oxide (IGZO) is centered in the larger processing temperatures required to achieve acceptable performance (>300 °C), not compatible with low-cost flexible substrates. This work reports for the first time flexible amorphous-ZTO TFTs processed at a maximum temperature of 180 °C. Different aspects are explored to obtain performance levels comparable to IGZO devices at these low processing temperatures, such as hydrogen incorporation during ZTO sputtering and integration with a high-κ multilayer/multicomponent dielectric. Close-to-zero turn-on voltage, field-effect mobility ≈5 cm2 V-1 s-1, and subthreshold slope of 0.26 V dec-1 are obtained. Stability under negative-bias-illumination stress is dramatically improved with hydrogen incorporation in ZTO and device performance is insensitive to bending under a radius of curvature of 15 mm. Inverters using the ZTO TFTs enable rail-to-rail operation with supply voltage V DD as low as 5 V, while a differential amplifier with positive feedback loop provides a gain of 17 dB and unity gain frequency of 40 kHz, limited by the large gate-to-source and gate-to-drain overlaps used herein.authorsversionpublishe