Low‐Noise and Large‐Linear‐Dynamic‐Range Photodetectors Based on Hybrid‐Perovskite Thin‐Single‐Crystals

Organic–inorganic halide perovskites are promising photodetector materials due to their strong absorption, large carrier mobility, and easily tunable bandgap. Up to now, perovskite photodetectors are mainly based on polycrystalline thin films, which have some undesired properties such as large defective grain boundaries hindering the further improvement of the detector performance. Here, perovskite thin‐single‐crystal (TSC) photodetectors are fabricated with a vertical p–i–n structure. Due to the absence of grain‐boundaries, the trap densities of TSCs are 10–100 folds lower than that of polycrystalline thin films. The photodetectors based on CH₃NH₃PbBr₃ and CH₃NH₃PbI₃ TSCs show low noise of 1–2 fA Hz^?1/2, yielding a high specific detectivity of 1.5 × 10¹³ cm Hz^1/2 W^?1. The absence of grain boundaries reduces charge recombination and enables a linear response under strong light, superior to polycrystalline photodetectors. The CH₃NH₃PbBr₃ photodetectors show a linear response to green light from 0.35 pW cm^?2 to 2.1 W cm^?2, corresponding to a linear dynamic range of 256 dB.     

High‐Tech‐Cellulose‐Funktionspolymere nach dem ALCERU®‐Verfahren

Functional High‐Tech‐Cellulose materials by the ALCERU® process Cellulose is one of the eldest materials of mankind. While the use of cellulose in former times was focused on application as a more construction or as a more textile material at present time the application profile turns to a more functional material using the ALCERU® process. Shaping of pure cellulose dissolution in NMMNO permits the manufacturing of materials for upholstery, filtration or biodegradable film strips having an uniform cross section. Fibreds, which can be applied in several packaging materials, are available using different techniques for regeneration cellulose. A great field of innovative functional cellulose materials is opened up by addition of several functional additives to cellulose dissolution. In this way piezo‐electrical conductive cellulose fibres (PZT) or high‐temperature filtration membranes are to be generated if one adds special types of ceramic powders. Above all PZT green fibres are applied in more recent uses as sensors or actuators. Electrically conductive cellulose fibres or filaments, which can be also used in the textile chain, can be prepared adding conductive carbon black to a cellulose dope on the same way, too. Cellulose material having adapted conductivity to different application is available by adding an exact defined amount of carbon black to cellulose dissolution. Finally cellulose beads can be manufactured by means of varied shaping technique. The beads are showing variable particle sizes and narrow pore size distribution. These properties open up very interesting application in the field of human blood purification or chromatography.     

Bimetal‐Organic‐Framework Derivation of Ball‐Cactus‐Like Ni‐Sn‐P@C‐CNT as Long‐Cycle Anode for Lithium Ion Battery

Metal phosphides are a new class of potential high‐capacity anodes for lithium ion batteries, but their short cycle life is the critical problem to hinder its practical application. A unique ball‐cactus‐like microsphere of carbon coated NiP₂/Ni₃Sn₄ with deep‐rooted carbon nanotubes (Ni‐Sn‐P@C‐CNT) is demonstrated in this work to solve this problem. Bimetal‐organic‐frameworks (BMOFs, Ni‐Sn‐BTC, BTC refers to 1,3,5‐benzenetricarboxylic acid) are formed by a two‐step uniform microwave‐assisted irradiation approach and used as the precursor to grow Ni‐Sn@C‐CNT, Ni‐Sn‐P@C‐CNT, yolk–shell Ni‐Sn@C, and Ni‐Sn‐P@C. The uniform carbon overlayer is formed by the decomposition of organic ligands from MOFs and small CNTs are deeply rooted in Ni‐Sn‐P@C microsphere due to the in situ catalysis effect of Ni‐Sn. Among these potential anode materials, the Ni‐Sn‐P@C‐CNT is found to be a promising anode with best electrochemical properties. It exhibits a large reversible capacity of 704 mA h g^?1 after 200 cycles at 100 mA g^?1 and excellent high‐rate cycling performance (a stable capacity of 504 mA h g^?1 retained after 800 cycles at 1 A g^?1). These good electrochemical properties are mainly ascribed to the unique 3D mesoporous structure design along with dual active components showing synergistic electrochemical activity within different voltage windows.     

A Dual‐Organic‐Transistor‐Based Tactile‐Perception System with Signal‐Processing Functionality

Organic‐device‐based tactile‐perception systems can open up new opportunities for the next generation of intelligent products. To meet the critical requirements of artificial perception systems, the efficient construction of organic smart elements with integrated sensing and signal processing functionalities is highly desired, but remains a challenge. This study presents a dual‐organic‐transistor‐based tactile‐perception element (DOT‐TPE) with biomimetic functionality by the construction of organic synaptic transistors with integrated sensing transistors. The unique geometry of the DOT‐TPE permits instantaneous sensing of pressure stimuli and synapse‐like processing of an electric signal in a single element. More importantly, these organic‐transistor‐based tactile‐perception elements can be built into arrays to serve as bionic tactile‐perception systems. The combined biomimetic functionality of tactile‐perception systems, together with their promising features of flexibility and large‐area fabrication, makes this work represent a step forward toward novel e‐skin devices for artificial intelligence.