Hongtao Liu

Hongtao Liu

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30
Publications
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3,359
Citations

Publications

Publications (30)
Article
Full-text available
Numerous studies conducted on the layered graphene family—including the monolayer, bilayer, trilayer, few‐layer, and multilayer—draw plenty of attention to stacking modes and twist angles, which are extensively explored for its controlled growth, properties, and applications. This review provides a comprehensive overview of current challenges and o...
Article
Full-text available
二维六方氮化硼是一种理想的石墨烯电学器件介电层材料, 然而, 制备低成本和高质量的氮化硼材料仍是一个挑战. 本文使用等离子体化学气相沉积法, 500°C下在铜箔衬底上制备了三角形的BN晶畴及其薄膜. 通过使用锡箔纸包裹原料的方法避免了残留原料在BN表面的沉积. 当BN作为石墨烯场效应晶体管的介电层时, 基于石墨烯的场效应器件空穴与电子的迁移率分别为10500和4750 cm² V‒1 s‒1, 明显优于在高温条件下制备的BN作为介电层的石墨烯器件, 间接表明了该方法可得到高质量的BN. 另外, 本工作也揭示了氮化硼的质量对石墨烯场效应器件的性能至关重要.
Article
Full-text available
In article number 1803961, a ferroelectric/electrochemical modulated synapse is developed as a neuromorphic readout element for an artificial visual‐perception system, as presented by Yunlong Guo, Wenping Hu, Yunqi Liu, and co‐workers. Through electrochemical doping and ferroelectric switching, the synapse produces three types of synaptic plasticit...
Article
Human eyes undertake the majority of information assimilation for learning and memory. Transduction of the color and intensity of the incident light into neural signals is the main process for visual perception. Besides light‐sensitive elements that function as rods and cones, artificial retinal systems require neuromorphic devices to transform lig...
Article
Human eyes use retina photoreceptor cells to absorb and distinguish photons from different wavelengths to construct an image. To emulate this process and extend its spectral response into NIR region, Yunlong Guo, Wenping Hu, Yunqi Liu and co-workers demonstrate a retina-like organic photosensor with wavelength-distinguishing and memory functionalit...
Article
Human eyes use retina photoreceptor cells to absorb and distinguish photons from different wavelengths to construct an image. Mimicry of such a process and extension of its spectral response into the near-infrared (NIR) is indispensable for night surveillance, retinal prosthetics, and medical imaging applications. Currently, NIR organic photosensor...
Article
With intrinsic mechanical flexibility, organic semiconductors are desirable for plastic optoelectronics. On page 624, via a combinatorial use of three organic semiconductors, W. P. Hu, Y. Q. Liu, and co-workers demonstrate an integrated, ultrathin (470 nm) photosensor that can enable greyscale sensing and signal amplification. The transconductance-...
Article
Large-area substitutional phosphorus-nitrogen co-doped monolayer graphene is directly synthesized on a Cu surface by chemical vapor deposition using molecules of phosphonitrilic chloride trimer as the phosphorus and nitrogen sources. The doping levels of both phosphorus and nitrogen atoms decrease as a function of the growth temperature. In contras...
Article
Y. Q. Liu, W. P. Hu, and co-workers demonstrate on page 4683 that the channel lengths of inkjet-printed transistors can be reduced to a sub-micrometer scale via a simple and direct method, without any sophisticated substrate-treatments with photolithography and organosilanes. By inkjet printing solvents on ultrathin poly(methyl methacrylate) (PMMA)...
Article
Hierarchical graphene architectures (HGAs) that grow by stacking of layers are produced on a liquid copper surface using chemical vapor deposition. The stacking mode - for example hexagonal-hexagonal-hexagonal or hexagonal-snowflake-dendritic - can be simply controlled. Measurements of the electrical properties of HGAs indicate that hierarchical st...
Article
Graphene free-standing film-like or paper-like materials have attracted great attention due to their intriguing electronic, optical and mechanical properties and potential application in chemical filters, molecular storage and supercapacitors. Although significant progress has been made in fabricating graphene films or paper, there is still no effe...
Article
By using tapping-mode AFM with a biased tip, the type of material (e.g.,metallic, n-, or p-type semiconductor) can be distinguished. Taking p-doping of graphene as an example, Y. Q. Liu, H. J. Gao and co-workers, on page 7015, observe a series of false apparent heights of graphene flakes when applying a series of different voltages on the tip. Howe...
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Article
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Swift fabrication of a non-covalently modified reduced graphene oxide electronic sensor has been developed. An unparalleled detection limit is demonstrated for Hg(2+), down to the picomolar range.
Article
A novel reducing reagent, Lawesson's reagent (LR), is used to directly reduce graphene oxide (GO) films and single GO sheets. The as-prepared reduced graphene oxide (GOLR) is fully characterized by XPS, Raman, FTIR, 13C NMR and XRD. Most of the oxygen-containing groups are efficiently removed by LR and the conjugated graphene networks are restored....
Article
Full-text available
Uniform single-crystal graphene domains were synthesized on copper foils by atmospheric pressure chemical vapor deposition with activated carbon dioxide (CO2). Controlled growth of graphene domains with a shape evolution from hexagonal to round has been achieved by varying the flow rate of CO2. The excess CO2 passivation induced graphene domain mor...
Article
Organic semiconductors (ITTI and IDTI) characterized of thieno[3,2-b]thiophene and dithiophene bridged isoindigo derivatives were designed and successfully synthesized. 1H–13C HMBC, 1H–1H nuclear Overhauser enhancement spectroscopy (NOESY) spectra, and 1H nuclear Overhauser enhancement (NOE) experiments were employed to determine the configurations...
Article
High-performance polymer semiconductors are highly desired in organic electronics. G. Yu, Y. Q. Liu, and co-workers develop two highly π-extended donor–acceptor copolymers based on diketopyrrolopyrrole and (E)-2-(2-(thiophen-2-yl) vinyl)thiophene units for applications in solutionprocessed polymer field-effect transistors. Stable high-performance t...
Article
Full-text available
A highly π-extended copolymer, PPTT, was developed based on 6H-phenanthro[1,10,9,8-cdefg]carbazole (PCZ) and thiazolo[5,4-d]thiazole derivative units, being the first PCZ-containing polymer, as well as its first applications in OTFTs and OPVs. This polymer exhibited an excellent solubility in several common organic solvents, a good film-forming abi...
Article
Taking advantage of the "coffee-ring" effect, graphene electrodes with channel lengths as low as 1-2 micrometers are patterned by inkjet printing. Organic thin film transistors and complementary inverters are also fabricated using these graphene electrodes and show excellent performance.
Article
Recently, a lot of effort has been focused on improving the performance and exploring the electric properties of graphene. This article presents a summary of chemical doping of graphene aimed at tuning the electronic properties of graphene. p-Type and n-type doping of graphene achieved through surface transfer doping or substitutional doping and th...
Article
An easy route to realize the assembly and reduction of graphene oxide (GO) sheets on a flexible plastic substrate by one step in GO solution is demonstrated. By virtue of this strategy, a flexible reduced GO sensor at an appointed position can be quickly realized from GO solution. This simple but effective and low-cost approach holds great promise...
Article
We report a simple method to produce graphene nanospheres (GNSs) by annealing graphene oxide (GO) solution at high-temperature with the assistance of sparks induced by the microwave absorption of graphite flakes dispersed in the solution. The GNSs were formed by rolling up of the annealed GO, and the diameters were mostly in the range 300–700 nm. T...
Article
A simple method for fabricating high-quality carbon nanoscrolls (CNSs) by exfoliation of natural flake graphite with the assistance of microwave sparks in liquid nitrogen is demonstrated. Field-effect transistors based on the CNSs show stable ambipolar behavior in both air and nitrogen, with maximum p-type and n-type mobilities in nitrogen of up to...
Article
A general route was demonstrated to realize the patterning of reduced graphene oxide sheets (RGOs) on a variety of substrates by a combination of modulating the solution wettability of the substrates and spin-coating process. By virtue of usual surface treatment technique or application of mixed solvent, the GO solution wettability can be controlle...
Article
A fused-seven-ring anthracene derivative with two sulfur bridges, benzobisthioxanthene (BTA), was synthesized, facilely. OLEDs employing BTA as the emitter exhibited bright (maximum 40,752 cd m(-2)) and efficient red emission (CIE, x = 0.64, y = 0.36) with a luminous efficiency of 4.4 cd A(-1).
Article
Large-flake graphene membranes up to 300 microm(2) can be exfoliated from graphite by oleyl amine based on solvothermal conditions. The exfoliated graphene sheets are of high quality and have few defects. The graphene dispersion, predominantly composed of monolayer graphene, had a high concentration of 0.15 mg ml(-1), and can be stabilized against...
Article
Asymmetrical heteroacene up to six fused rings, tetraceno[2,3-b]benzo[d]thiophene (TBT), was synthesized facilely and its physicochemical properties and device applications were investigated. Field-effect transistors (FETs) fabricated with TBT as semiconducting layers showed carrier mobility up to 0.13 cm2 V−1 s−1. The transistors also exhibited a...
Article
A new rigid cyclic thiophene molecule was synthesized and its unusual and interesting single-crystal tubular products on a millimeter scale were obtained unexpectedly by a simple self-assemble technique in a solution process under ambient conditions.

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