Inspired by human brains, optoelectronic synapses are expected as one of significant steps for constructing neuromorphic systems. In addition, intensive attention has been paid to biodegradable and biocompatible materials for developing green electronics. In this regard, environmentally friendly organic optoelectronic synaptic transistors based on wood-derived cellulose nanopaper (WCN) as dielectric/substrate and nature chlorophyll-a as photoactive material are demonstrated. Both WCN and chlorophyll-a are biocompatible and biodegradable materials from natural organisms. Versatile synaptic behaviors have been well mimicked by the modulation of both electrical and optical signals. More significantly, optical wireless communication is experimentally emulated and the information processing capability is also verified in pattern recognition simulation. Furthermore, the flexible synaptic transistors exhibit no apparent synaptic performance degradation even when the bending radius is reduced to 1 mm. Our work may develop a promising approach for the development of green and flexible electronics in neuromorphic visual systems.

Infrared (IR) photodetection is important for light communications, military, agriculture, and related fields. Organic transistors are investigated as photodetectors. However, due to their large band gap, most organic transistors can only respond to ultraviolet and visible light. Here high performance IR phototransistors with ternary semiconductors of organic donor/acceptor complex and semiconducting single‐walled carbon nanotubes (SWCNTs), without deep cooling requirements are developed. Due to both the ultralow intermolecular electronic transition energy of the complex and charge transport properties of SWCNTs, the phototransistor realizes broadband photodetection with photoresponse up to 2600 nm. Moreover, it exhibits outstanding performance under 2000 nm light with photoresponsivity of 2.75 × 106 A W−1, detectivity of 3.12 × 1014 Jones, external quantum efficiency over 108%, and high Iphoto/Idark ratio of 6.8 × 105. The device exhibits decent photoresponse to IR light even under ultra‐weak light intensity of 100 nW cm−2. The response of the phototransistor to blackbody irradiation is demonstrated, which is rarely reported for organic phototransistors. Interestingly, under visible light, the device can also be employed as synaptic devices, and important basic functions are realized. This strategy provides a new guide for developing high performance IR optoelectronics based on organic transistors.

In the past decades, with the increasing awareness of personal health management, various types of flexible and wearable body sensors have been developed. Thanks to the superiorities of advanced wearable technologies, including miniaturization and portability, stretchability and comfortability, intelligent human-machine interface, etc., flexible and wearable body sensors hold great promise in the next generation biomedicine and healthcare applications. Unfortunately, the data precision, response speed, sensitivity and selectivity, durability, compatibility with flexible substrates, and preparation technics still need to be enhanced and refined to meet the requirements of clinical evaluations or even commercialization. According to the working principles, flexible and wearable sensing platform can be roughly divided into four categories: physical sensors, chemical sensors, biosensors, and the fusion of different types of sensors. Here, a brief review focused on recent developments of these flexible and wearable sensors applied especially to biomedicine and healthcare is presented. In addition, the existing challenges and potential opportunities ahead in flexible and wearable sensor technologies are discussed. At last, an outlook of wearable sensing platforms in biomedicine and healthcare is proposed. We hope this review can provide guidance for superior flexible and wearable sensing technologies in the future.

Developing synaptic devices with environmental-friendly materials is a promising research direction. Here, light-stimulated synaptic transistors based on natural carotene and organic semiconductors were developed. Several important functions similar to biological...

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Neuromorphic visual system with image perception, memory, and preprocessing functions is expected to simulate basic features of the human retina. Organic optoelectronic synaptic transistors emulating biological synapses may be promising candidates for constructing neural morphological visual system. However, the sensing wavelength range of organic optoelectronic synaptic transistors usually limits their potential in artificial multispectral visual perception. Here, retina‐inspired optoelectronic synaptic transistors that present broadband responses covering ultraviolet, visible, and near‐infrared regions are demonstrated, which leverage the wide‐range photoresponsive charge trapping layer and the heterostructure formed between PbS quantum dots and organic semiconductor. Simplified neuromorphic visual arrays are developed to simulate comprehensive image perception, memory, and preprocessing functions. Benefitting from the flexibility of the charge trapping and organic semiconductor layers, a flexible neuromorphic visual array can be fabricated, having an ultralow power consumption of 0.55 fJ per event under a low operating voltage of −0.01 V. More significantly, an accelerating image preprocessing effect can be observed in a wide wavelength range even beyond the perception range of the human visual system, due to the gate‐adjustable synaptic plasticity. These devices are highly promising for implementing neuromorphic visual systems with broadband perception, increasing image processing efficiency, and promoting the development of artificial vision.