All-inorganic perovskite quantum dots (APQDs) have emerged as excellent materials which have been widely used in numerous micro-nano photoelectric devices. However, resistive random access memory (RRAM) devices based on APQDs are relatively scarce. In this work, RRAM based on CsPbBr3 APQDs prepared by the solution processed method was fabricated at room temperature. The sandwich structure memory device shows high reproducibility, good data retention ability, and light assisted multilevel storage capability. The resistance ratio (ON/OFF) of the RRAM device between the high resistance state and the low resistance state reaches almost 107. Additionally, the device exhibits high performances under low power consumption—low reading voltage (−0.3 V) and operation voltage (−2.4 V/1.55 V). It is suggested that the connection and rupture of conducting filaments, which are formed by Br vacancies under an electric field, are responsible for the resistive switching effect. Our work provides an opportunity to develop the next generation high-performance and stable nonvolatile memory devices.
25 September 2020 in The Journal of Physical Chemistry C
Humidity sensors allow electronic devices to convert the water content in the environment into electronical signals by utilizing material properties and transduction techniques. Three-dimensional graphene foam (3DGF) can be exploited in humidity sensors due to its convenient features including low-mass density, large specific surface area, and excellent electrical. In this paper, 3DGF with super permeability to water enables humidity sensors to exhibit a broad relative humidities (RH) range, from 0% to 85.9%, with a fast response speed (response time: ~89 ms, recovery time: ~189 ms). To interpret the physical mechanism behind this, we constructed a 3DGF model decorated with water to calculate the energy structure and we carried out the CASTEP as implemented in Materials Studio 8.0. This can be ascribed to the donor effect, namely, the electronic donation of chemically adsorbed water molecules to the 3DGF surface. Furthermore, this device can be used for user interaction (UI) with unprecedented performance. These high performances support 3DGF as a promising material for humidity sensitive material.
All-inorganic cesium lead bromine (CsPbBr 3 ) perovskites quantum dots (QDs) are one of the most photoelectric materials due to their high absorption coefficient, pronounced quantum-size effect, tunable optical property. Here, a self-powered PD based on all-inorganic CsPbBr 3 perovskites QDs is fabricated and demonstrated. The light-induced pyroelectric effect is utilized to modulate the optoelectronic processes without the external power supply. The working mechanism of the PD is carefully investigated upon 532 nm laser illumination and the minimum recognizable response time of the self-powered PD is 1.5 μ s, which are faster than those of most previously reported wurtzite nanostructure PDs. Meanwhile, the frequency and temperature independence of the self-powered PD are experimented and summarized. The self-powered PD with high performance is expected to have extensive applications in solar cell, energy harvesting, resistive random access memory.
Because they possess excellent visible light absorption properties, lead-free colloidal copper-based chalcogenide quantum dots (QDs) have emerged in photoelectronic fields. By means of localized surface plasmonic resonance (LSPR), the absorption properties of QDs can be enhanced. In this paper, we fabricate a lead-free QD field effect phototransistor (FEpT) by utilizing the LSPR enhancement of Au nanoparticles (NPs). The plasmonic FEpT demonstrates responsivity up to and a specific detectivity of Jones at zero bias under illumination by a 532 nm laser, values that are enhanced by approximately 200% more than devices without Au NPs. Particularly, the FEpT exhibits a multi-wavelength response, which is photoresponsive to 405, 532, and 808 nm irradiations, and presents stability and reproducibility in the progress of ON–OFF cycles. Furthermore, the enhancement induced by Au NP LSPR can be interpreted by finite-difference time domain simulations. The low-cost solution-based process and excellent device performance strongly underscore lead-free QDs as a promising material for self-powered photoelectronic applications, which can be further enhanced by Au NP LSPR.