Jiahui Liu

Bio: Jiahui Liu is an academic researcher from Fuzhou University. The author has contributed to research in topics: Quantum dot & Lithium. The author has an hindex of 5, co-authored 22 publications receiving 100 citations.

Encapsulation of Fe3O4 Nanoparticles into N, S co-Doped Graphene Sheets with Greatly Enhanced Electrochemical Performance

Abstract: Particular N, S co-doped graphene/Fe3O4 hybrids have been successfully synthesized by the combination of a simple hydrothermal process and a subsequent carbonization heat treatment. The nanostructures exhibit a unique composite architecture, with uniformly dispersed Fe3O4 nanoparticles and N, S co-doped graphene encapsulant. The particular porous characteristics with many meso/micro holes/pores, the highly conductive N, S co-doped graphene, as well as the encapsulating N, S co-doped graphene with the high-level nitrogen and sulfur doping, lead to excellent electrochemical performance of the electrode. The N-S-G/Fe3O4 composite electrode exhibits a high initial reversible capacity of 1362.2 mAhg−1, a high reversible specific capacity of 1055.20 mAhg−1 after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 556.69 mAhg−1 when cycled at the current density of 1000 mAg−1, indicating that the N-S-G/Fe3O4 composite is a promising anode candidate for Li-ion batteries.

A review of stability-enhanced luminescent materials: fabrication and optoelectronic applications

Abstract: Luminescent materials such as Cd-based quantum dots, CuInS2 quantum dots, and perovskite-based materials play an important role as an exceptional class of optoelectronic materials due to their unique and novel characteristics for optoelectronic applications. However, a key challenge for luminescent materials and devices is their poor long-term stability, which is typically attributed to the irreversible changes of surface ligands or chemical structure against oxygen and moisture when exposed to ambient atmosphere. Thus, this review mainly focuses on recent important work on the stability-enhanced strategies of luminescent materials. Various strategies for their fabrication, including surface engineering and surface coating routes have been summarized, followed by their advantages and challenges. Furthermore, the corresponding optoelectronic applications of these promising stability-enhanced luminescent materials in light-emitting diodes, photodetectors, solid-state lighting chips, and solar cells were also reviewed. Afterward, the outlook and perspective are presented.

Weak Light-Stimulated Synaptic Hybrid Phototransistors Based on Islandlike Perovskite Films Prepared by Spin Coating.

Abstract: An artificial synaptic device that can provide color discrimination, image storage, and image recognition is highly required to mimic the human vision for biological robots. All-inorganic halide perovskites have attracted extensive attention for the reason of their high stability and favorable photoelectric properties. In this study, a light-stimulated synaptic phototransistor based on a CsPbBr3/organic semiconductor hybrid film is reported. The fabricated CsPbBr3 film exhibits an island structure, which reduces the hysteresis effectively and at the same time achieves a high specific detectivity of up to 2 × 1015 Jones. The decay of the photocurrent can be delayed by changing the gate bias, which is essential for achieving high-performance light-stimulated synaptic devices. Due to the outstanding detectivity of the device, the obvious synaptic functions can be observed when triggered by a light signal with a power of 1.6 nW that is much weaker than previous most perovskite-based hybrid synaptic phototransistors under a low operating voltage of -1 V. The electrical power consumption of the device could be as low as 0.076 pJ when the power of light spike was 7.36 nW. Taking into account this characterization, with changing of light intensity or wavelength, the contrast of the image was enlarged, which can further promote the image recognition accuracy. More significantly, this CsPbBr3/TIPS hybrid film can be fabricated by facile and low-cost solution processes. This study indicates the great potential of solution-processed perovskite-based light-stimulated synapses for future artificial visual systems.

Ultrastable Quantum Dot Composite Films under Severe Environments.

Abstract: Semiconductor quantum dots (QDs) have attracted extensive attention because of their remarkable optical and electrical characteristics. However, the practical application of QDs and further the QD composite films have greatly been hindered mainly owing to their essential drawbacks of extreme unstability under oxygen and water environments. Herein, one simple method has been employed to enhance enormously the stability of Cd xZn1- xSe yS1- y QD composite films by a combination of Cd xZn1- xSe yS1- y QDs and poly(vinylidene) fluoride (PVDF), which is characteristic of closely arranged molecular chains and strong hydrogen bonds. There are many particular advantages in using QD/PVDF composite films such as easy processing, low cost, large-area fabrication, and especially extreme stability even in the boiling water for more than 240 min. By employing K2SiF6:Mn4+ as a red phosphor, a prototype white light-emitting diode (WLED) with color coordinates of (0.3307, 0.3387), Tc of 5568 K, and color gamut 112.1NTSC(1931)% at 20 mA has been fabricated, and there is little variation under different excitation currents, indicating that the QD/PVDF composite films fabricated by this simple blade-coating process make them ideal candidates for liquid-crystal display backlight utilization via assembling a WLED on a large scale owing to its ultrahigh stability under severe environments.

Graphene-based materials for capacitive deionization

Abstract: Capacitive deionization is an emerging technology for energy-efficient water desalination and has attracted more and more attention in recent years. The capacitive deionization technology is based on ion electrosorption at the surface of a pair of electrically charged electrodes, which are commonly composed of carbon materials. Among numerous electrode materials, graphene-based materials are outstanding, playing a vital role during the deionization process due to their intriguing features. After a brief introduction of the theory and instruments of capacitive deionization, we systematically summarize the current progress in graphene nanosheets, porous graphene, graphene-based composites, surface tuned graphene and its composites as electrodes for capacitive deionization. We also present our perspectives on the development of graphene-based electrodes for capacitive deionization.

Synthesis of Fe3O4/carbon foams composites with broadened bandwidth and excellent electromagnetic wave absorption performance

Abstract: Fabricating of bio-derived electromagnetic wave absorbing materials has become hotspot. However, many bio-derived absorbers still suffer from thicker matching thickness limiting their application. Herein, porous carbon foams derived from fish skin have been synthesized through a simple hydrothermal method for the first time. Then Fe3O4 nanospheres with diameter of 30 nm were uniformly imbedded into the carbon matrix via refluxing and annealing treatment. By controlling the precursor ratio of Fe(NO3)3·9H2O and carbon, optimized microstructure and component can be easily realized. As expected, the novel Fe3O4/C foams show outstanding electromagnetic wave absorption performance compared with single carbon foams. When the loading filler ratio was 25 wt%, the minimum RL value of FC-3 can reach −47.3 dB with a small matching thickness of 1.9 mm. Moreover, the effective absorption bandwidth was 5.68 GHz (12.16–17.84 GHz) with the thickness of 2.2 mm. The thin matching thickness could ascribe to the addition of Fe3O4 nanospheres which could introduce more dielectric loss and magnetic loss. Moreover, the matching thickness of FC-3 is much thinner than other reported bio-derived materials. This investigation could be a perspective paving for the fabrication and mechanism research of electromagnetic wave absorber derived from animal organs.

Recent Advances in 3D Graphene Architectures and Their Composites for Energy Storage Applications.

Abstract: Graphene is widely applied as an electrode material in energy storage fields. However, the strong π-π interaction between graphene layers and the stacking issues lead to a great loss of electrochemically active surface area, damaging the performance of graphene electrodes. Developing 3D graphene architectures that are constructed of graphene sheet subunits is an effective strategy to solve this problem. The graphene architectures can be directly utilized as binder-free electrodes for energy storage devices. Furthermore, they can be used as a matrix to support active materials and further improve their electrochemical performance. Here, recent advances in synthesizing 3D graphene architectures and their composites as well as their application in different energy storage devices, including various battery systems and supercapacitors are reviewed. In addition, their challenges for application at the current stage are discussed and future development prospects are indicated.