Zhi Zhang

Dr. Zhi Zhang

University of Electronic Science and Technology of China, Zhongshan Institute
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 December 2019 in Micromachines
Verified
Journal Article
Open access
PDF file
Zichuan YiZichuan Yi
Zichuan Yi
WFWenyong Feng
Wenyong Feng
LWLi Wang
Li Wang
LLLiming Liu
Liming Liu
YLYue Lin
Yue Lin
GZGuofu Zhou
Guofu Zhou
Electrowetting display (EWD) performance is severely affected by ink distribution and charge trapping in pixel cells. Therefore, a multi structural driving waveform is proposed for improving the aperture ratio of EWDs. In this paper, the hysteresis characteristic (capacitance–voltage, C-V) curve of the EWD pixel is tested and analyzed for obtaining the driving voltage value at the inflection point of the driving waveform. In the composition of driving waveform, a voltage slope is designed for preventing ink dispersion and a reverse pulse is designed for releasing the trapped charge which is caused by hysteresis characteristic. Finally, the frequency and the duty cycle of the driving waveform are optimized for the max aperture ratio by a series of testing. The experimental results show that the proposed driving waveform can improve the ink dispersion behavior, and the aperture ratio of the EWD is about 8% higher than the conventional driving waveform. At the same time, the response speed of the driving waveform can satisfy the dynamic display in EWDs, which provides a new idea for the design of the EWD driving scheme.

16 April 2021 in Micromachines
Verified
Journal Article
Open access
PDF file
QGQingguo Gao
Qingguo Gao
CZChongfu Zhang
Chongfu Zhang
KYKaiqiang Yang
Kaiqiang Yang
XPXinjian Pan
Xinjian Pan
ZZZhi Zhang
Zhi Zhang
LLLiming Liu
Liming Liu
Two-dimensional (2D) MoS2 have attracted tremendous attention due to their potential applications in future flexible high-frequency electronics. Bilayer MoS2 exhibits the advantages of carrier mobility when compared with monolayer mobility, thus making the former more suitable for use in future flexible high-frequency electronics. However, there are fewer systematical studies of chemical vapor deposition (CVD) bilayer MoS2 radiofrequency (RF) transistors on flexible polyimide substrates. In this work, CVD bilayer MoS2 RF transistors on flexible substrates with different gate lengths and gigahertz flexible frequency mixers were constructed and systematically studied. The extrinsic cutoff frequency (fT) and maximum oscillation frequency (fmax) increased with reducing gate lengths. From transistors with a gate length of 0.3 μm, we demonstrated an extrinsic fT of 4 GHz and fmax of 10 GHz. Furthermore, statistical analysis of 14 flexible MoS2 RF transistors is presented in this work. The study of a flexible mixer demonstrates the dependence of conversion gain versus gate voltage, LO power and input signal frequency. These results present the potential of CVD bilayer MoS2 for future flexible high-frequency electronics.

20 August 2020 in Nanomaterials
Verified
Journal Article
Open access
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ZZZhi Zhang
Zhi Zhang
Zichuan YiZichuan Yi
Zichuan Yi
LLLiming Liu
Liming Liu
JYJianjun Yang
Jianjun Yang
CZChongfu Zhang
Chongfu Zhang
FCFeng Chi
Feng Chi
Lithium-sulfur battery (LSB) will become the next generation energy storage device if its severe shuttle effect and sluggish redox kinetics can be effectively addressed. Here, a unique three-dimensional hollow reduced graphene oxide microsphere decorated with ZnO nanoparticles (3D-ZnO/rGO) is synthesized to decrease the dissolution of lithium polysulfide (LiPS) into the electrolyte. The chemical adsorption of ZnO on LiPS is combined with the physical adsorption of 3D-rGO microsphere to synergistically suppress the shuttle effect. The obtained 3D-ZnO/rGO can provide sufficient space for sulfur storage, and effectively alleviate the repeated volume changes of sulfur during the cycle. When the prepared S-3D-ZnO/rGO was used as the cathode in LSB, an initial discharge specific capacity of 1277 mAh g−1 was achieved at 0.1 C. After 100 cycles, 949 mAh g−1 can still be maintained. Even at 1 C, a reversible discharge specific capacity of 726 mAh g−1 was delivered.

9 November 2022 in Micromachines
Verified
Journal Article
Open access
PDF file
JYJianjun Yang
Jianjun Yang
JLJiaxuan Liu
Jiaxuan Liu
YLYaxin Li
Yaxin Li
XYXiaobao Yu
Xiaobao Yu
Zichuan YiZichuan Yi
Zichuan Yi
LLLiming Liu
Liming Liu
The electrolyte is one of the key components of dye-sensitized solar cells’ (DSSC) structure. In this paper, the electrolyte formulation of a new DSSC with external photoanode structure was studied. Based on the idea that the electrolyte should match the light absorption and light path, iodine series electrolytes with different concentrations were configured and used in the experiment. The results showed that the external photoanode structure solar cells assembled with titanium electrode had the best photoelectric conversion ability when the concentration of I2 was 0.048 M. It achieved the open circuit voltage of 0.71 V, the short circuit current of 8.87 mA, and the filling factor of 57%.

3 November 2023 in Nanomaterials
Verified
Journal Article
Open access
PDF file
JYJianjun Yang
Jianjun Yang
XWXiansheng Wang
Xiansheng Wang
XYXiaobao Yu
Xiaobao Yu
JLJiaxuan Liu
Jiaxuan Liu
ZZZhi Zhang
Zhi Zhang
JYJunsheng Yu
Junsheng Yu
Based on the PM6:Y6 binary system, a novel non-fullerene acceptor material, D18-Cl, was doped into the PM6:Y6 blend to fabricate the active layer. The effects of different doping ratios of D18-Cl on organic solar cells were investigated. The best-performing organic solar cell was achieved when the doping ratio of D18-Cl reached 20 wt%. It exhibited a short-circuit current of 28.13 mA/cm2, a fill factor of 70.25%, an open-circuit voltage (Voc) of 0.81 V, and a power conversion efficiency of 16.08%. The introduction of an appropriate amount of D18-Cl expanded the absorption spectrum of the active layer, improved the morphology of the active layer, reduced large molecular aggregation and defects, minimized bimolecular recombination, and optimized the collection efficiency of charge carriers. These results indicate the critical importance of selecting an appropriate third component in binary systems and optimizing the doping ratio to enhance the performance of ternary organic solar cells.

17 June 2021 in Nanomaterials
Verified
Journal Article
Open access
PDF file
QGQingguo Gao
Qingguo Gao
CZChongfu Zhang
Chongfu Zhang
PLPing Liu
Ping Liu
YHYunfeng Hu
Yunfeng Hu
KYKaiqiang Yang
Kaiqiang Yang
FCFeng Chi
Feng Chi
As an atomically thin semiconductor, 2D molybdenum disulfide (MoS2) has demonstrated great potential in realizing next-generation logic circuits, radio-frequency (RF) devices and flexible electronics. Although various methods have been performed to improve the high-frequency characteristics of MoS2 RF transistors, the impact of the back-gate bias on dual-gate MoS2 RF transistors is still unexplored. In this work, we study the effect of back-gate control on the static and RF performance metrics of MoS2 high-frequency transistors. By using high-quality chemical vapor deposited bilayer MoS2 as channel material, high-performance top-gate transistors with on/off ratio of 107 and on-current up to 179 μA/μm at room temperature were realized. With the back-gate modulation, the source and drain contact resistances decrease to 1.99 kΩ∙μm at Vbg = 3 V, and the corresponding on-current increases to 278 μA/μm. Furthermore, both cut-off frequency and maximum oscillation frequency improves as the back-gate voltage increases to 3 V. In addition, a maximum intrinsic fmax of 29.7 GHz was achieved, which is as high as 2.1 times the fmax without the back-gate bias. This work provides significant insights into the influence of back-gate voltage on MoS2 RF transistors and presents the potential of dual-gate MoS2 RF transistors for future high-frequency applications.