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Electrochemical Performance of Potassium Bromate Active Electrolyte for Laser-Induced KBr-Graphene Supercapacitor Electrodes. INORGANICS 2023. [DOI: 10.3390/inorganics11030109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
Abstract
In this paper, we have reported a low-concentration active electrolyte of KBrO3 for the supercapacitor’s application. The electrochemical processes were carried out in two concentrations of KBrO3 with 0.2 and 0.4 M. Additionally, we have reported a novel strategy for doping graphene during its fabrication process with a potassium bromide (KBr) solution. The chemical doping of graphene with KBr improved the electrochemical properties of graphene used as supercapacitors. HRTEM images confirmed the multi-layer graphene obtained by CO2 laser based on polyimide. The effect of KBr on the graphene lattice has been studied using Raman spectroscopy. The two electrodes of graphene and KBr-doped graphene were subjected to the electrochemical properties study as a supercapacitor by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge techniques. The results exhibited the successful method of graphene doping and the stability of using KBrO3 as a suitable electrolyte for electrochemical processes with this lower molarity. The specific capacitance of the pristine graphene capacitor in 0.2 M of KBrO3 was 33 Fg−1, while this value increased up to 70 Fg−1 for KBr-doped graphene in 0.4 M of KBrO3. The specific capacity in mAhg−1 has also increased twofold. The results exhibited the possibility of using KBrO3 as an electrolyte. The supercapacitor performance almost showed good stability in the life cycle.
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Ali A, Kim SY, Hussain M, Jaffery SHA, Dastgeer G, Hussain S, Anh BTP, Eom J, Lee BH, Jung J. Deep-Ultraviolet (DUV)-Induced Doping in Single Channel Graphene for Pn-Junction. NANOMATERIALS 2021; 11:nano11113003. [PMID: 34835767 PMCID: PMC8623685 DOI: 10.3390/nano11113003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/05/2021] [Accepted: 11/07/2021] [Indexed: 11/24/2022]
Abstract
The electronic properties of single-layer, CVD-grown graphene were modulated by deep ultraviolet (DUV) light irradiation in different radiation environments. The graphene field-effect transistors (GFETs), exposed to DUV in air and pure O2, exhibited p-type doping behavior, whereas those exposed in vacuum and pure N2 gas showed n-type doping. The degree of doping increased with DUV exposure time. However, n-type doping by DUV in vacuum reached saturation after 60 min of DUV irradiation. The p-type doping by DUV in air was observed to be quite stable over a long period in a laboratory environment and at higher temperatures, with little change in charge carrier mobility. The p-doping in pure O2 showed ~15% de-doping over 4 months. The n-type doping in pure N2 exhibited a high doping effect but was highly unstable over time in a laboratory environment, with very marked de-doping towards a pristine condition. A lateral pn-junction of graphene was successfully implemented by controlling the radiation environment of the DUV. First, graphene was doped to n-type by DUV in vacuum. Then the n-type graphene was converted to p-type by exposure again to DUV in air. The n-type region of the pn-junction was protected from DUV by a thick double-coated PMMA layer. The photocurrent response as a function of Vg was investigated to study possible applications in optoelectronics.
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Affiliation(s)
- Asif Ali
- HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea; (A.A.); (M.H.); (S.H.A.J.); (S.H.); (B.T.P.A.)
| | - So-Young Kim
- Center for Semiconductor Technology Convergence, Department of Electrical Engineering, Pohang University of Science and Technology, Cheongam-ro 77, Nam-gu, Pohang 37673, Korea; (S.-Y.K.); (B.H.L.)
| | - Muhammad Hussain
- HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea; (A.A.); (M.H.); (S.H.A.J.); (S.H.); (B.T.P.A.)
| | - Syed Hassan Abbas Jaffery
- HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea; (A.A.); (M.H.); (S.H.A.J.); (S.H.); (B.T.P.A.)
| | - Ghulam Dastgeer
- Department of Physics & Astronomy, Graphene Research Institute-Texas Photonics Center International Research Center (GRI–TPC IRC), Sejong University, Seoul 05006, Korea; (G.D.); (J.E.)
| | - Sajjad Hussain
- HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea; (A.A.); (M.H.); (S.H.A.J.); (S.H.); (B.T.P.A.)
| | - Bach Thi Phuong Anh
- HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea; (A.A.); (M.H.); (S.H.A.J.); (S.H.); (B.T.P.A.)
| | - Jonghwa Eom
- Department of Physics & Astronomy, Graphene Research Institute-Texas Photonics Center International Research Center (GRI–TPC IRC), Sejong University, Seoul 05006, Korea; (G.D.); (J.E.)
| | - Byoung Hun Lee
- Center for Semiconductor Technology Convergence, Department of Electrical Engineering, Pohang University of Science and Technology, Cheongam-ro 77, Nam-gu, Pohang 37673, Korea; (S.-Y.K.); (B.H.L.)
| | - Jongwan Jung
- HMC (Hybrid Materials Center), Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Korea; (A.A.); (M.H.); (S.H.A.J.); (S.H.); (B.T.P.A.)
- Correspondence:
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Elahi E, Khan MF, Rehman S, Khalil HMW, Rehman MA, Kim DK, Kim H, Khan K, Shahzad M, Iqbal MW, Basit MA, Khan F. Enhanced electrical and broad spectral (UV-Vis-NIR) photodetection in a Gr/ReSe 2/Gr heterojunction. Dalton Trans 2020; 49:10017-10027. [DOI: 10.1039/d0dt01164a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Excellent electrical and photoelectrical study of vertical integration by layered two-dimensional materials having gate tunable broad spectral (UV-Vis-NIR) light detection response.
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Affiliation(s)
- Ehsan Elahi
- Department of Physics
- Riphah International University
- Lahore
- Pakistan
| | | | - Shania Rehman
- Department of Electrical Engineering
- Sejong University
- Gwangjin-gu
- Korea
| | - H. M. Waseem Khalil
- Department of Electrical Engineering
- College of Engineering and Technology
- University of Sargodha
- Pakistan
| | - Malik Abdul Rehman
- School of Mechanical Engineering
- Yonsei University
- Seodaemun-gu
- South Korea
| | - Deok-kee Kim
- Department of Electrical Engineering
- Sejong University
- Gwangjin-gu
- Korea
| | - Honggyun Kim
- Department of Electrical Engineering
- Sejong University
- Gwangjin-gu
- Korea
| | - Karim Khan
- School of Electrical Engineering & Intelligentization
- Dongguan University of Technology (DGUT)
- Dongguan
- China
- Institute of Microscale Optoelectronics
| | - Moazzam Shahzad
- Federal Urdu University of Science and Technology G-7/1
- Islamabad
- Pakistan
| | | | - Muhammad Abdul Basit
- Department of Materials Science and Engineering
- Institute of Space Technology
- Islamabad 44000
- Pakistan
| | - Fasihullah Khan
- Davision of Electronics and Electrical Engineering
- Dongguk University
- 04620 Seoul
- Korea
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A Label-Free and Ultrasensitive Immunosensor for Detection of Human Chorionic Gonadotrophin Based on Graphene FETs. BIOSENSORS-BASEL 2017; 7:bios7030027. [PMID: 28704926 PMCID: PMC5618033 DOI: 10.3390/bios7030027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 06/24/2017] [Accepted: 07/03/2017] [Indexed: 02/01/2023]
Abstract
We report on a label-free immunosensor based on graphene field effect transistors (G-FETs) for the ultrasensitive detection of Human Chorionic Gonadotrophin (hCG), as an indicator of pregnancy and related disorders, such as actopic pregnancy, choriocarcinoma and orchic teratoma. Pyrene based bioactive ester was non-covalently anchored onto the graphene channel in order to retain the sp² lattice. The G-FET transfer characteristics showed repeatable and reliable responses in all surface modifying steps using a direct current (DC) readout system. The hCG concentration gradient showed a detection limit of ~1 pg·mL-1. The proposed method facilitates the cost-effective and viable production of graphene point-of-care devices for clinical diagnosis.
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Khan MF, Nazir G, lermolenko VM, Eom J. Electrical and photo-electrical properties of MoS 2 nanosheets with and without an Al 2O 3 capping layer under various environmental conditions. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2016; 17:166-176. [PMID: 27877867 PMCID: PMC5101887 DOI: 10.1080/14686996.2016.1167571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 03/13/2016] [Accepted: 02/25/2016] [Indexed: 05/25/2023]
Abstract
The electrical and photo-electrical properties of exfoliated MoS2 were investigated in the dark and in the presence of deep ultraviolet (DUV) light under various environmental conditions (vacuum, N2 gas, air, and O2 gas). We examined the effects of environmental gases on MoS2 flakes in the dark and after DUV illumination through Raman spectroscopy and found that DUV light induced red and blue shifts of peaks (E12 g and A1 g) position in the presence of N2 and O2 gases, respectively. In the dark, the threshold voltage in the transfer characteristics of few-layer (FL) MoS2 field-effect transistors (FETs) remained almost the same in vacuum and N2 gas but shifted toward positive gate voltages in air or O2 gas because of the adsorption of oxygen atoms/molecules on the MoS2 surface. We analyzed light detection parameters such as responsivity, detectivity, external quantum efficiency, linear dynamic range, and relaxation time to characterize the photoresponse behavior of FL-MoS2 FETs under various environmental conditions. All parameters were improved in their performances in N2 gas, but deteriorated in O2 gas environment. The photocurrent decayed with a large time constant in N2 gas, but decayed with a small time constant in O2 gas. We also investigated the characteristics of the devices after passivating by Al2O3 film on the MoS2 surface. The devices became almost hysteresis-free in the transfer characteristics and stable with improved mobility. Given its outstanding performance under DUV light, the passivated device may be potentially used for applications in MoS2-based integrated optoelectronic circuits, light sensing devices, and solar cells.
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Affiliation(s)
- Muhammad Farooq Khan
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University, Seoul05006, Korea
| | - Ghazanfar Nazir
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University, Seoul05006, Korea
| | - Volodymyr M. lermolenko
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University, Seoul05006, Korea
| | - Jonghwa Eom
- Department of Physics & Astronomy and Graphene Research Institute, Sejong University, Seoul05006, Korea
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