Neuromorphic computing has considerable potential in simulating the efficient information processing capabilities of the human brain. Implementing neuromorphic computing requires the development of artificial synaptic devices that mimic biological synapses, which are the basic for information processing, storage, and transmission in biological neural networks. Herein, we demonstrate a light-stimulated synaptic transistor (LSST) device based on graphene/hexagonal boron nitride (h-BN)/pentacene heterojunction for emulating the basic functions of the human brain. The LSST devices can detect light stimulus at a wavelength of 520 nm and exhibits a variety of typical synaptic properties, such as excitatory postsynaptic current, paired pulse facilitation, and transition from short-term memory to long-term memory. In addition, the LSST device is capable of simulating the learning and forgetting processes of the human brain. Based on the optically and electrically controlled conductivity modulation characteristics of the LSST device, we construct an artificial neural network for perform pattern recognition tasks, and recognition accuracy of handwritten digits is 88.5%. These results mean that our LSST devices have great potential for future applications in neuromorphic computing.
Flexible pressure sensor is essential in various applications, including health monitoring, soft robots, and human machine interfaces. However, it is a challenge to fabricate high-performance flexible pressure sensor with high sensitivity and wide detection range. Herein, inspired by the microstructure of skin epidermis, a flexible piezoresistive pressure sensor with micro-papillae structure is proposed. Polydimethylsiloxane (PDMS) with rough surface molded from abrasive paper is utilized as the flexible substrate. Then, the conductive multiwalled carbon nanotube (MWCNT) film is deposited on the prepared substrate via spray-coating method to form MWCNT-PDMS membrane. A piezoresistive pressure sensor is obtained by putting two as-prepared membranes face-to-face. For comparison, a sensor with flat PDMS is prepared through the same method. Results show that the micro-papillae structure pressure sensor achieves a 5.79-fold increase in pressure sensitivity (11.93 kPa-1) compared to that of the pressure sensor with flat PDMS (2.06 kPa-1). Meanwhile, the structured pressure sensor exhibits a wide detection range (0.04-107 kPa), rapid response (179 ms), and excellent stability over 1000 cycles. Furthermore, finite element analysis (FEA) is conducted to investigate the influence of micropapillae structure on the sensing performance of sensor. Under force loading, a homogeneous stress distribution of the sensor with flat PDMS is observed, while the stress of the sensor with micro-papillae structure is concentrated on the micro-papillae, which enhances the sensitivity of sensor. Finally, the structured pressure sensor is utilized to monitor human physiological signals and different human motions, including breathing rate, feet movement, and finger bending.
Organic-inorganic hybrid perovskite solar cells have been widely recognized as an excellent candidate for next-generation photovoltaic devices because of their easy processing and rapidly developing power conversion efficiency (PCE). Owing to the fact that the interface is sensitive to photoelectric conversion properties, many strategies are used to improve the interface wettability between perovskite precursor solution and the hole transport layer (HTL). In this study, we report a method of argon plasma treatment on the poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) layer which could effectively enhance the wettability because of the improvement in the chemical compositions and film morphologies of PEDOT:PSS. In contrast to untreated films, the wettability of PEDOT:PSS is increased by 3.3, 3.6 and 3.7 times based on the optimization of plasma power, treating time, and pressure, respectively. We also systematically described the timeliness of wettability from 0 to 8 hours after plasma treatment. The interface wettability shows a down trend with increasing storage time.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.