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Black phosphorus (BP), as an emerging successor to layered two-dimensional materials, has attracted extensive interest in cancer therapy. Toxicological studies on BP are of great importance for potential biomedical applications, yet not systemically explored. Herein, toxicity and oxidative stress of BP quantum dots (BPQDs) at cellular, tissue, and whole-body levels are evaluated by performing the systemic in vivo and in vitro experiments. In vitro investigations show that BPQDs at high concentration (200 μg/mL) exhibit significant apoptotic effects on HeLa cells. In vivo investigations indicate that oxidative stress, including lipid peroxidation, reduction of catalase activity, DNA breaks, and bone marrow nucleated cells (BMNC) damage, can be induced by BPQDs transiently but recovered gradually to healthy levels. No apparent pathological damages are observed in all organs, especially in the spleen and kidneys, during the 30-day period. This work clearly shows that BPQDs can cause acute toxicities by oxidative stress responses, but the inflammatory reactions can be recovered gradually with time for up to 30 days. Thus, BPQDs do not give rise to long-term appreciable toxicological responses.

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. [ABSTRACT FROM AUTHOR]

An all-inorganic cesium lead halide quantum dot (QD) based Au nanoparticle (NP) floating-gate memory with a solution processed layer-by-layer method is demonstrated. Easy synthesis at room temperature and excellent stability make all-inorganic CsPbBr3 perovskite QDs suitable as a semiconductor layer in low voltage nonvolatile transistor memory. The bipolarity of QDs has both electrons and holes stored in the Au NP floating gate, resulting in bidirectional shifts of initial threshold voltage according to the applied programing and erasing pulses. Under low operation voltage (±5 V), the memory achieved a great memory window (∼2.4 V), long retention time (>105 s), and stable endurance properties after 200 cycles. So the proposed memory device based on CsPbBr3 perovskite QDs has a great potential in the flash memory market. [ABSTRACT FROM AUTHOR]

In this work, TiO 2 nanorod arrays (TiO 2 -NAs) were modified by CuInS 2 quantum dots (CuInS 2 QDs) on the surface of the nanorods. The resultant TiO 2 -CuInS 2 nanorod arrays (TiO 2 -CuInS 2 -NAs) were characterized by UV/Vis spectroscopy, transmission electronic microscopy (TEM), and X-ray diffraction (XRD). The TiO 2 -CuInS 2 -NAs were applied as scaffold for the preparation of organic-inorganic hybrid perovskite solar cells. In comparison with the solar cell devices based on TIO 2 -NAs, a significant improvement in the power conversion efficiency had been achieved and the highest efficiency was obtained as 11.7% (under 100 mW/cm 2 ) through the optimization of the growth time of QDs on nanorods. The improvement of the device performance could be attributed to the assistance of CuInS 2 QDs in the light harvesting as well as the facilitation of the electron injection from the perovskite to the TiO 2 scaffold. [ABSTRACT FROM AUTHOR]

In the present work, poly-TPD and TCTA composite hole transport layer (HTL) was employed in solution processed CdSe/ZnS quantum dot light emitting diodes (QLEDs). As the doping level of TCTA can determine the carriers transport efficiency of HTL, the proper mixing ratio of TCTA and poly-TPD should be found to optimize the performance of composite HTL for QLEDs. The doping of poly-TPD by low TCTA content can make its HOMO level lower and then reduce the energy barrier height from HTL to quantum dots (QDs), whereas the doping of poly-TPD by the concentrated TCTA results in the degraded performance of QLEDs due to its decreased hole transport mobility. By using the optimized composition with poly-TPD:TCTA (3:1) as the hole transport layer, the luminescence of the device exhibits about double enhancement compared with that of poly-TPD based device. The improvement of luminescence is mainly attributed to the lower energy barrier of hole injection. The Förster resonant energy transfer (FRET) mechanism in the devices was investigated through theoretical and experimental analysis and the results indicate that the TCTA doping makes no difference on FRET. Therefore, the charge injection mechanism dominates the improved performance of the devices. [ABSTRACT FROM AUTHOR]

We develop a composite photoanode by sensitizing TiO nanorod arrays with PbS quantum dots (QDs) and CdS QDs. Benefitted from additional introduced PbS QDs and CdS QDs onto TiO, the absorption of the composite photoanodes are broaden from UV to visible region. The experimental results showed that the PbS sandwiched between TiO and CdS cannot only broad the absorption properties but also improve the stability. The stability can be explained by the hole facile transmission from PbS to CdS because of the valence band offsets between PbS and CdS which cause a small energy barrier and reduce the hole accumulation. The photocurrent density reached 1.35 mA cm at 0.9716 V vs. RHE (0 V vs. Ag/AgCl, under 60 mW cm illumination) for TiO/PbS/CdS. The highest photocurrent of TiO/PbS/CdS can be explained by the smallest of total resistance (138 Ω cm) compared to TiO/CdS and pristine TiO. [ABSTRACT FROM AUTHOR]

Perovskites have attracted substantial attention on account of their excellent physical properties and simple preparation process. Here we demonstrated an improved photodetector based on solution-processing organic-inorganic hybrid perovskite CH3NH3PbI3−xClx layer decorated with CsPbBr3 perovskite quantum dots. The CH3NH3PbI3−xClx-CsPbBr3 photodetector was operated in a visible light region, which appeared high responsivity (R = 0.39 A/W), detectivity (D* = 5.43 × 109 Jones), carrier mobility (μp = 172 cm2 V−1 s−1 and μn = 216 cm2 V−1 s−1), and fast response (rise time 121 μs and fall time 107 μs). The CH3NH3PbI3−xClx-CsPbBr3 heterostructure is anticipated to find comprehensive applications in future high-performance photoelectronic devices. [ABSTRACT FROM AUTHOR]

Write Once Read Many (WORM) Memory, as one of the most important nonvolatile memory type, has widespread used in a variety of permanent storage applications in the Big Data age. As an excellent material, CsPbBr 3 quantum dots have widely used in a lot of photoelectric devices, but CsPbBr 3 quantum dots based memory device remain to be studied. In this work a WORM memory device based on CsPbBr 3 quantum dots is demonstrated. The CsPbBr 3 QDs based WORM shows great reproducibility, good data retention ability, irreversible electrical transition from the high resistance state (HRS) or OFF state to the low resistance state (LRS) or ON state and the resistance ratio (ON/OFF) can reach almost 104. Additionally, the device exhibits high performances under low power consumption — low reading voltage (−0.5 V) and writing voltage (−1.1V). To study the CsPbBr 3 QDs based WORM provides an opportunity to develop the next generation high-performance and stable WORM devices. • We present a sandwiched WORM based on CsPbBr 3 AIPQDs by solution processed method. • Our CsPbBr 3 AIPQDs based WORM shows great reproducibility, good data retention ability. • The resistance ratio (ON/OFF) of the WORM device between the OFF and ON state can reach almost 104. • Additionally, the device exhibits high performances under low power consumption — low reading voltage (−0.5V) and operation voltage (−1.1V). [ABSTRACT FROM AUTHOR]

Imitation of memory and learning behaviors of nervous system by nanoscale photoelectric devices is highly desirable for building neuromorphic systems or even artificial neural networks. In this work, artificial synapses with photoelectric plasticity and memory behaviors based on a charge trapping memristive system was fabricated. Versatile synaptic functions, such as photoelectric excitatory postsynaptic current behavior, short-term memory, long-term memory, short - to long-term memory transition, and photonic learning and forgetting behaviors, were all mimicked by applied pulses of light and electricity. Moreover, the device also has the potential to be used in flexible applications. The photoelectric plasticity and memory phenomenon can be attributed to charge trapping and detrapping, since the used CdSe/ZnS quantum dots with a quantum well structure that act as trapping centers. This work provides a cost-effective method to develop artificial synapse devices, neural networks, and computers with photoelectric operations. Unlabelled Image • Artificial synapses based on CdSe/ZnS quantum dots and CsPbBr 3 quantum dots was fabricated. • Photoelectric synaptic plasticity and memory behaviors were mimicked by applied pulses of light and electricity. • The quantum well structure of CdSe/ZnS act as the trapping centers, playing role for the plasticity and memory behaviors. • Bending tests show the device possesses an excellent mechanical flexibility. [ABSTRACT FROM AUTHOR]