Pain‐perceptual nociceptors (PPN) are essential sensory neurons that recognize harmful stimuli and can empower the human body to react appropriately and perceive precisely unusual or dangerous conditions in the real world. Furthermore, the sensitization‐regulated nociceptors (SRN) can greatly assist pain‐sensitive human to reduce pain sensation by normalizing hyperexcitable central neural activity. Therefore, the implementation of PPNs and SRNs in hardware using emerging nanoscale devices can greatly improve the efficiency of bionic medical machines by giving them different sensitivities to external stimuli according to different purposes. However, current most‐normal organic/oxide transistors face a great challenge due to channel scaling, especially in the sub‐10 nm channel technology. Here, a sub‐10 nm indium‐tin‐oxide transistor with an ultrashort vertical channel as low as ≈3 nm, using sodium alginate bio‐polymer electrolyte as gate dielectric, is demonstrated. This device can emulate important characteristics of PPN such as pain threshold, memory of prior injury, and pain sensitization/desensitization. Furthermore, the most intriguing character of SRN can be achieved by tuning the channel thickness. The proposed device can open new avenues for the fascinating applications of next‐generation neuromorphic brain‐like systems, such as bio‐inspired electronic skins and humanoid robots.

Highly efficient and reproducible cesium (Cs) doped triple cation (Cs, methylammonium (MA) and formamidinium (FA)) lead trihalide perovskite planar heterojunction (PHJ) solar cells are fabricated via low-temperature process with a simple architecture of ITO/SnO 2 /Perovskite/Spiro-OMeTAD/ Ag, of which the power conversion efficiency (PCE) up to 20.51% with negligible hysteresis and a steady output PCE of 20.22% can be achieved. Cs-intercalation is useful for forming high-quality Cs-doped triple cation perovskite films with larger gains and band gap as compared with perovskite films without Cs doping, leading to impressively enhanced photoluminescence lifetime and open circuit voltage (V oc ). Meanwhile, incorporating Cs þ into perovskite structure can result in lower charge-extraction time and prolonged charge-recombination lifetime, which are advantageous to improve the device performance. More importantly, Cs-doped triple cation PHJ perovskite solar cells (PSCs) exhibit better stability. They could maintain about 80% original PCE even exposed to air environments (humidity %40%) for over 500 hr without any encapsulation, while similar ones without Csdoping only maintain about 60% original PCE. The research work demonstrates that triple or multiple cation mixture is an effective strategy for structuring highly-efficient and stable PHJ-PSCs via low-temperature process, which may accelerate the commercialization of PSCs fabricated via large-scale printing techniques.

Transient electronics, a new generation of electronics that can physically or functionally vanish on demand, are very promising for future "green" security biocompatible electronics. At the same time, hardware implementation of biological synapses is highly desirable for emerging brain-like neuromorphic computational systems that could look beyond the conventional von Neumann architecture. Here, a hardware-security physically-transient bidirectional artificial synapse network based on a dual in-plane-gate Al-Zn-O neuromorphic transistor was fabricated on free-standing laterally-coupled biopolymer electrolyte membranes (sodium alginate). The excitatory postsynaptic current, paired-pulse-facilitation, and temporal filtering characteristics from high-pass to low-pass transition were successfully mimicked. More importantly, bidirectional dynamic spatiotemporal learning rules and neuronal arithmetic were also experimentally demonstrated using two lateral in-plane gates as the presynaptic inputs. Most interestingly, excellent physically-transient behavior could be achieved with a superfast water-soluble speed of only ∼120 seconds. This work represents a significant step towards future hardware-security transient biocompatible intelligent electronic systems.

Organic photomemory based on heterojunction phototransistor has been fabricated utilizing vanadyl-phthalocyanine (VOPc) on para-sexiphenyl (p-6P) thin films. Under 365 nm ultraviolet light irradiation, the ratio of photocurrent and dark current (I ph/I dark) and photoresponsivity of phototransistors are about 1.5 × 105 and 87 A/W, respectively. Such devices can transduce the input light signals into electrical signals and the output signals can be stored for recording the light simulation. After applying a light pulse (4.2 mW/cm2, 100 ms) on the device, the stored current level lasted for ∼5000 s with only a 20% decrease, indicating a good photomemory behavior. Importantly, the photomemory behavior is effectively modulated by gate voltage. Multilevel photomemory behaviors are observed by modulating light pulse duration and light power intensity. Because of the construction of type-I heterojunction, the superior photomemory characteristics are mainly originated from efficient charge trapping at VOPc/p-6P interface. In situ current sensitive atomic force microscopy (CSAFM) is used for monitoring surface current of the VOPc/p-6P heterojunctions. A change of conductivity in grains is observed upon 365 nm light illumination. After turning off the light, the current of grains did not rapidly decrease, but displayed the behavior of photomemory. This study provides a guide for designing high-performance organic photomemory devices.

The interfacial electronic structure at the organic–inorganic semiconductor interface plays an important role in determining the electrical and optical performance of organic-based devices. Here, we studied the molecular alignment and electronic structure of thermally deposited 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) molecules on cleaved black phosphorus using photoelectron spectroscopy. The work function of black phosphorus is substantially upped with an organic thin film, originating from the charge transfer from black phosphorus to PTCDA. According to our photoemission spectrum and theoretical simulation, we also define the interaction between PTCDA and black phosphorus as weak van de Waals physisorption, rather than bonding chemisorption. Furthermore, we show that PTCDA thin film can effectively isolate reactive oxygen species, thereby protecting BP surface oxidation and deterioration under ambient conditions. Our results suggest the possibility of manipulating interfacial electronic structures of black phosphorus interface by noncovalent with organic semiconductor, in particular for applications in high-performance organic–inorganic hybrid photovoltaic.

Highly efficient CsPbI2Br planar heterojunction (PHJ) perovskite solar cells (PSCs) with a structure of ITO/SnO2/CsPbI2Br/Spiro-OMeTAD/Ag are fabricated via a low-temperature solution process. A flash annealing technique is used to produce high-quality CsPbI2Br perovskite films with high density and uniformity, as well as highly crystallized CsPbI2Br films. These CsPbI2Br films are used as the light-harvesting layer in PHJ PSC devices using SnO2 as the electron transport layer and Spiro-OMeTAD as the hole transport layer. Based on the measurement of the energy levels via ultraviolet photoelectron spectroscopy, it indicates that there is a very good interfacial band alignment between SnO2 and CsPbI2Br, supporting the efficient electron extraction from CsPbI2Br to SnO2. Thus, simple structural CsPbI2Br PHJ PSCs with power conversion efficiencies (PCEs) up to 13.09% are achieved, which is comparable to the highest reported PCEs for all-inorganic PHJ PSCs. The findings show that the PHJ device architecture, instead of a mesoporous structure, can be used to fabricate highly efficient inorganic PSCs with a simple structure, offering the advantages of matching well the low-cost, high-throughout roll-to-roll printing process.

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Two dimensional atomic crystals, like grapheme (G) and molybdenum disulfide (MoS 2 ), exhibit great interest in electronic and optoelectronic applications. The excellent physical properties, such as transparency, semiconductivity, and flexibility, make them compatible with current organic electronics. Here, we review recent progress in the understanding of the interfaces of van der Waals (vdW) heterostructures between small organic molecules (pentacene, copper phthalocyanine (CuPc), perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), and dioctylbenzothienobenzothiophene (C 8 -BTBT)) and layered substrates (G, MoS 2 and hexagonal boron nitride (h-BN)). The influences of the underlying layered substrates on the molecular arrangement, electronic and vibrational properties will be addressed.