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Organic phototransistors can enable many important applications such as nonvolatile memory, artificial synapses, and photodetectors in next‐generation optical communication and wearable electronics. However, it is still a challenge to achieve a big memory window (threshold voltage response ∆Vth) for phototransistors. Here, a nanographene‐based heterojunction phototransistor memory with large ∆Vth responses is reported. Exposure to low intensity light (25.7 µW cm−2) for 1 s yields a memory window of 35 V, and the threshold voltage shift is found to be larger than 140 V under continuous light illumination. The device exhibits both good photosensitivity (3.6 × 105) and memory properties including long retention time (>1.5 × 105 s), large hysteresis (45.35 V), and high endurance for voltage‐erasing and light‐programming. These findings demonstrate the high application potential of nanographenes in the field of optoelectronics. In addition, the working principle of these hybrid nanographene‐organic structured heterojunction phototransistor memory devices is described which provides new insight into the design of high‐performance organic phototransistor devices. [ABSTRACT FROM AUTHOR]

Metal oxide (MO) semiconductors are widely used in electronic devices due to their high optical transmittance and promising electrical performance. This work describes the advancement toward an eco‐friendly, streamlined method for preparing thin‐film transistors (TFTs) via a pure water‐solution blade‐coating process with focus on a low thermal budget. Low temperature and rapid annealing of triple‐coated indium oxide thin‐film transistors (3C‐TFTs) and indium oxide/zinc oxide/indium oxide thin‐film transistors (IZI‐TFTs) on a 300 nm SiO2 gate dielectric at 300 °C for only 60 s yields devices with an average field effect mobility of 10.7 and 13.8 cm2 V−1 s−1, respectively. The devices show an excellent on/off ratio (>106), and a threshold voltage close to 0 V when measured in air. Flexible MO‐TFTs on polyimide substrates with AlOx dielectrics fabricated by rapid annealing treatment can achieve a remarkable mobility of over 10 cm2 V−1 s−1 at low operating voltage. When using a longer post‐coating annealing period of 20 min, high‐performance 3C‐TFTs (over 18 cm2 V−1 s−1) and IZI‐TFTs (over 38 cm2 V−1 s−1) using MO semiconductor layers annealed at 300 °C are achieved. [ABSTRACT FROM AUTHOR]

Advanced polymeric materials, such as polyether ether ketones (PEEK), have been placed as direct substitutes for metals and ceramics in diverse applications, such as the machinery industry and biomedical engineering. Moreover, surface treatments allow the emergence of brand‐new properties or the improvement of preexisting ones, such as friction, lubrication, wettability, cellular infiltration, or osseointegration. A paramount approach to achieving topographical modifications is by using laser micro/nanoprocessing techniques such as direct laser interference patterning (DLIP). Herein, PEEK foils are structured with DLIP method using ultrashort pulses. The influence of the pulse duration between 266 fs and 15 ps and the pulse‐to‐pulse overlap on the resulting surface topography and chemistry is assessed. As a result, well‐defined line‐like textures with a period of 5.8 μm and aspect ratios up to 0.88 are achieved. Furthermore, it is possible to explore and understand the behavior of surface phenomena such as swelling, increase/decrease of laser–material interaction onset, and laser‐induced periodic surface structures formation. A comprehensive topographical and chemical characterization study demonstrates that these distinctive topographical features occur because of multiphoton absorption, incubation effects, and heat accumulation. These phenomena allow structuring polymeric substrates that are low‐absorbing and challenging to pattern with conventional nanosecond infrared (IR) laser sources. [ABSTRACT FROM AUTHOR]

Engineering the energetics of perovskite solar cells through the introduction of surface dipoles that assist with charge carrier extraction is a promising route to enhance the device performance without altering other device layers or fabrication parameters. In this work, we introduce four different derivatives of dicationic phosphonium-bridged ladder stilbenes (PYMC) in inverted perovskite solar cells with the device structure of ITO/Meo-2pacz/perovskite/PYMC/phenyl-C61-butyric acid methyl ester (PCBM)/bathocuproine/Ag. We show that the derivatives introduce a dipole at the perovskite/PCBM interface, which for derivatives with suitable energy levels can enhance the charge carrier extraction, leading to a quenched photoluminescence of perovskite thin films and an improved photovoltaic performance. As a result, both a higher average and maximum power conversion efficiency could be achieved and an overall better device reproducibility. This work highlights the significant potential of energetics engineering between perovskites and transport layers in perovskite solar cells for highly efficient photovoltaic devices. [ABSTRACT FROM AUTHOR]

• Stainless steel surfaces were patterned by Direct Laser Interference Patterning. • Samples were then colorized by growing an oxide layer by Direct Laser Writing. • Achieved structural colors were quantitively characterized. • Anti-counterfeit features could be engraved on the colorized surfaces. Structural colors can be induced on metals not only to fabricate logos or decorative motives but also to embed anti-counterfeit features for product protection. In this study, stainless steel (EN 1.4301) plates are colorized by growing a thin oxide layer using direct laser writing (DLW) and hidden anti-counterfeit measures are included on their surfaces by direct laser interference patterning (DLIP) processing. The periodic microstructures resulting from the DLIP treatment have a spatial period of 1 µm and act as relief diffraction gratings, featuring a characteristic diffraction pattern. These microstructures are not visible to the human eye but are easily detectable upon shining a coherent beam on the surface. Furthermore, the reflectance over the visible spectrum of the colorized surfaces with and without the DLIP microtexture is measured, giving low differences in the color perception following the so-called "CIE L*a*b*" color space. Finally, a demonstrator is fabricated, in which colorized fields with and without the security features are shown. [ABSTRACT FROM AUTHOR]