Artificial visual system with information sensing, processing, and memory function is promoting the development of artificial intelligence techniques. Photonic synapse as an essential component can enhance the visual information processing efficiency owing to the high propagation speed, low latency, and large bandwidth. Herein, photonic synaptic transistors based on organic semiconductor poly­[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di­(thien-2-yl)­thieno [3,2-b]­thiophene)] (DPPDTT) and perovskite CsPbBr3 quantum dots are fabricated by a simple solution process. The device can simulate fundamental synaptic behaviors, including excitatory postsynaptic current, pair-pulse facilitation, the transition of short-term memory to long-term memory, and “learning experience” behavior. Combining the advantages of the high photosensitivity of perovskites and relatively high conductivity of DPPDTT, the device can exhibit excellent synaptic performances at a low voltage of −0.2 V. Even under an ultralow operation voltage of −0.0005 V, the device can still show obvious synaptic responses. Tunable synaptic integration behaviors including “AND” and “OR” light logic functions can be realized. An artificial visual system is successfully emulated by illuminating the synaptic arrays employing light of different densities. Therefore, low-voltage synaptic devices based on organic semiconductor and CsPbBr3 quantum dots with a simple fabrication technique present high potential to mimic human visual memory.

Lead‐free perovskite materials are exhibiting bright application prospects in photodetectors (PDs) owing to their low toxicity compared with traditional lead perovskites. Unfortunately, their photoelectric performance is constrained by the relatively low charge conductivity and poor stability. In this work, photoresponsive transistors based on stable lead‐free bismuth perovskites CsBi3I10 and single‐walled carbon nanotubes (SWCNTs) are first reported. The SWCNTs significantly strengthen the dissociation and transportation of the photogenerated charge carriers, which lead to dramatically improved photoresponsivity, while a decent Ilight/Idark ratio over 102 can be maintained with gate modulation. The devices exhibit high photoresponsivity (6.0 × 104 A W−1), photodetectivity (2.46 × 1014 jones), and external quantum efficiency (1.66 × 105%), which are among the best reported results in lead‐free perovskite PDs. Furthermore, the excellent stability over many other lead‐free perovskite PDs is demonstrated over 500 h of testing. More interestingly, the device also shows the application potential as a light‐stimulated synapse and its synaptic behaviors are demonstrated. In summary, the lead‐free bismuth perovskite‐based hybrid phototransistors with multifunctional performance of photodetection and light‐stimulated synapse are first demonstrated in this work.

Flexible photodetectors (FPDs) have been receiving increasing attention in recent years because of their potential applications in electronic eyes, bioinspired sensing, smart textiles, and wearable devices. Moreover, metal halide perovskites (MHPs) with outstanding optical and electrical properties, good mechanical flexibility, lowcost and low-temperature solution-processed fabrication have become promising candidates as light harvesting materials in FPDs. Herein, we comprehensively review the developments of FPDs based on MHPs reported recently. This review firstly provides an introduction with respect to the performance parameters and device configurations of perovskite photodetectors, followed by the specific requirements of FPDs including substrate and electrode materials. Next, chemical compositions, structures and preparation methods of MHPs are presented. Then, the FPDs on the basis of single-component perovskite and hybrid structure perovskite are discussed, subsequently, self-powered flexible perovskite photodetectors were presented. In the end, conclusions and challenges are put forward in the field of FPDs based on perovskites. K E Y W O R D S metal halide perovskites, flexible photodetectors, self-powered

SummaryAlthough age‐related ovarian failure in female mammals cannot be reversed, recent strategies have focused on improving reproductive capacity with age, and rapamycin is one such intervention that has shown a potential for preserving the ovarian follicle pool and preventing premature ovarian failure. However, the application is limited because of its detrimental effects on follicular development and ovulation during long‐term treatment. Herein, we shortened the rapamycin administration to 2 weeks and applied the protocol to both young (8 weeks) and middle‐aged (8 months) mouse models. Results showed disturbances in ovarian function during and shortly after treatment; however, all the treated animals returned to normal fertility 2 months later. Following natural mating, we observed prolongation of ovarian lifespan in both mouse models, with the most prominent effect occurring in mice older than 12 months. The effects of transient rapamycin treatment on ovarian lifespan were reflected in the preservation of primordial follicles, increases in oocyte quality, and improvement in the ovarian microenvironment. These data indicate that short‐term rapamycin treatment exhibits persistent effects on prolonging ovarian lifespan no matter the age at initiation of treatment. In order not to disturb fertility in young adults, investigators should in the future consider applying the protocol later in life so as to delay menopause in women, and at the same time increase ovarian lifespan.

synaptic functions is fundamental to the realization of brain-like computing.Recently, many research advances have been made in the field of artificial synapses, [4] such as memristors, [5] phasechange memory, [6] and field-effect transistors [7] have been exploited to simulate synaptic behaviors. Notably, interest has arisen in organic synaptic transistors, [8] which can combine the advantages of organic electronics, such as low cost, flexibility, and ease of solution fabrication, together with the benefit of multi-terminal synaptic devices for more controllable test parameters. [9] Compared to conventional planar transistors, vertical organic field-effect transistors (VOFETs) are structurally different. [10] Attributing to their adjustable channel lengths determined by the thickness of active layers, they can be simply controlled to sub-micron level or nanometer level in channel length. Small channel length implies high on-state conductance and low voltage operation for the device. [11] The characteristics of VOFETs are consistent with requirements for low voltage operation and low energy consumption of artificial synaptic devices. Furthermore, VOFETs have some potentially unique advantages. Large-scale integration of devices can be achieved through crossbar stacking owing to the vertical electrode placement. The vertical current flow in VOFET could be more tolerant of channel cracks caused by device bending or stretching, [12] which provides a promising approach for the next generation of flexible microelectronic devices.Here, we have fabricated photonic synaptic devices with the structure of VOFETs for the first time. In our work, vertical structure transistors have been designed and constructed, in which networks of single-walled carbon nanotubes (SWCNTs) served as the bottom electrode, CsPbBr 3 quantum dots (QDs) were selected as light-harvesting material, a p-type organic polymer semiconductor, poly[2,5-bis(2-octyldodecyl)pyrrolo [3,4c]pyrrole-1,4(2H,5H)-dione-3,6-diyl)-alt-(2,2′;5′,2″;5‴,2‴quaterthiophen-5,5‴-diyl)] (PDPP4T), was used as the channel material. PEDOT: PSS (conductive polymer) acted as the top transparent electrode, which could transmit light signals for synaptic activities owing to its transparency. In this photonic synaptic device, typical functions of biological synapses, such as excitatory post-synaptic current (EPSC), short-term plasticity (STP), and long-term plasticity (LTP), have been successfully Artificial synapses have shown great potential in the research of artificial intelligence and brain-like computing. Artificial synaptic devices based on vertical organic field-effect transistors (VOFETs) exhibit shorter carrier transmission distances and more stable source-drain currents than conventional planar organic transistors due to their smaller channel lengths. By taking advantage of the vertical structure, low working voltage can be achieved. Here, vertical synaptic devices with working voltage as low as 10 µV and ultra-low power consumption (≈1.3 fJ per spike) are proposed....