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ElAfandy RT, Ebaid M, Min JW, Zhao C, Ng TK, Ooi BS. Flexible InGaN nanowire membranes for enhanced solar water splitting. OPTICS EXPRESS 2018; 26:A640-A650. [PMID: 30114053 DOI: 10.1364/oe.26.00a640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/21/2018] [Indexed: 06/08/2023]
Abstract
III-Nitride nanowires (NWs) have recently emerged as potential photoelectrodes for efficient solar hydrogen generation. While InGaN NWs epitaxy over silicon is required for high crystalline quality and economic production, it leads to the formation of the notorious silicon nitride insulating interface as well as low electrical conductivity which both impede excess charge carrier dynamics and overall device performance. We tackle this issue by developing, for the first time, a substrate-free InGaN NWs membrane photoanodes, through liftoff and transfer techniques, where excess charge carriers are efficiently extracted from the InGaN NWs through a proper ohmic contact formed with a high electrical conductivity metal stack membrane. As a result, compared to conventional InGaN NWs on silicon, the fabricated free-standing flexible membranes showed a 10-fold increase in the generated photocurrent as well as a 0.8 V cathodic shift in the onset potential. Through electrochemical impedance spectroscopy, accompanied with TEM-based analysis, we further demonstrated the detailed enhancement within excess charge carrier dynamics of the photoanode membranes. This novel configuration in photoelectrodes demonstrates a novel pathway for enhancing the performance of III-nitrides photoelectrodes to accelerate their commercialization for solar water splitting.
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Hussain S, Tavakoli MM, Waleed A, Virk US, Yang S, Waseem A, Fan Z, Nadeem MA. Nanotextured Spikes of α-Fe 2O 3/NiFe 2O 4 Composite for Efficient Photoelectrochemical Oxidation of Water. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3555-3564. [PMID: 29537275 DOI: 10.1021/acs.langmuir.7b02786] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We demonstrate for the first time the application of p-NiFe2O4/n-Fe2O3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe2O4/n-Fe2O3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe2O4 and Fe2O3) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe2O4/n-Fe2O3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured p-NiFe2O4/n-Fe2O3 device with equal molar 1:1 ratio of NiFe2O4 and Fe2O3 was found to be highly efficient for PEC water oxidation as compared with pure hematite, 1:2 and 1:3 molar ratios of composite. The photocurrent density of 1:1 composite thin film on planar substrate was equal to 1.07 mA/cm2 at 1.23 VRHE, which was 1.7 times higher current density as compared with pure hematite device (0.63 mA/cm2 at 1.23 VRHE). The performance of p-NiFe2O4/n-Fe2O3 composites in PEC water oxidation was further enhanced by their deposition over 3D-NSP substrate. The highest photocurrent density of 2.1 mA/cm2 at 1.23 VRHE was obtained for the 1:1 molar ratio p-NiFe2O4/n-Fe2O3 composite on NSP (NF1-NSP), which was 3.3 times more photocurrent density than pure hematite. The measured applied bias photon-to-current efficiency (ABPE) value of NF1-NSP (0.206%) was found to be 1.87 times higher than that of NF1-P (0.11%) and 4.7 times higher than that of pure hematite deposited on FTO-coated glass (0.044%). The higher PEC water oxidation activity of p-NiFe2O4/n-Fe2O3 composite thin film as compared with pure hematite is attributed to the Z-path scheme and better separation of electrons and holes. The increased surface area and greater light absorption capabilities of 3D-NSP devices result in further improvement in catalytic activities.
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Affiliation(s)
- Shabeeb Hussain
- Catalysis and Nanomaterials Lab 27, Department of Chemistry , Quaid-i-Azam University , Islamabad 45320 , Pakistan
| | - Mohammad Mahdi Tavakoli
- Department of Electronic and Computer Engineering , Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong SAR , China
- Department of Materials Science and Engineering , Sharif University of Technology , Azadi Street , 113659466 Tehran , Iran
| | - Aashir Waleed
- Department of Electronic and Computer Engineering , Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong SAR , China
- Department of Electrical Engineering , University of Engineering and Technology , Lahore (FSD Campus), 3.5 km, Khurrianwala-Makuana Bypass , Faisalabad 38000 , Pakistan
| | - Umar Siddique Virk
- Department of Electronic and Computer Engineering , Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong SAR , China
- Department of Mechatronics and Control Engineering , University of Engineering and Technology , Lahore (FSD Campus), 3.5 km, Khurrianwala-Makuana Bypass , Faisalabad 38000 , Pakistan
| | - Shihe Yang
- Department of Chemistry, William Mong Institute of Nano Science and Technology , The Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong SAR , Hong Kong
| | - Amir Waseem
- Catalysis and Nanomaterials Lab 27, Department of Chemistry , Quaid-i-Azam University , Islamabad 45320 , Pakistan
| | - Zhiyong Fan
- Department of Electronic and Computer Engineering , Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong SAR , China
| | - Muhammad Arif Nadeem
- Catalysis and Nanomaterials Lab 27, Department of Chemistry , Quaid-i-Azam University , Islamabad 45320 , Pakistan
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Narangari PR, Karuturi SK, Lysevych M, Hoe Tan H, Jagadish C. Improved photoelectrochemical performance of GaN nanopillar photoanodes. NANOTECHNOLOGY 2017; 28:154001. [PMID: 28301329 DOI: 10.1088/1361-6528/aa61ed] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this work, we report on the photoelectrochemical (PEC) investigation of n-GaN nanopillar (NP) photoanodes fabricated using metal organic chemical vapour deposition and the top-down approach. Substantial improvement in photocurrents is observed for GaN NP photoanodes compared to their planar counterparts. The role of carrier concentration and NP dimensions on the PEC performance of NP photoanodes is further elucidated. Photocurrent density is almost doubled for doped NP photoanodes whereas no improvement is noticed for undoped NP photoanodes. While the diameter of GaN NP is found to influence the onset potential, carrier concentration is found to affect both the onset and overpotential of the electrodes. Optical and electrochemical impedance spectroscopy characterisations are utilised to further explain the PEC results of NP photoanodes. Finally, improvement in the photostability of NP photoanodes with the addition of NiO as a co-catalyst is investigated.
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Affiliation(s)
- Parvathala Reddy Narangari
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
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Varadhan P, Fu HC, Priante D, Retamal JRD, Zhao C, Ebaid M, Ng TK, Ajia I, Mitra S, Roqan IS, Ooi BS, He JH. Surface Passivation of GaN Nanowires for Enhanced Photoelectrochemical Water-Splitting. NANO LETTERS 2017; 17:1520-1528. [PMID: 28177248 DOI: 10.1021/acs.nanolett.6b04559] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydrogen production via photoelectrochemical water-splitting is a key source of clean and sustainable energy. The use of one-dimensional nanostructures as photoelectrodes is desirable for photoelectrochemical water-splitting applications due to the ultralarge surface areas, lateral carrier extraction schemes, and superior light-harvesting capabilities. However, the unavoidable surface states of nanostructured materials create additional charge carrier trapping centers and energy barriers at the semiconductor-electrolyte interface, which severely reduce the solar-to-hydrogen conversion efficiency. In this work, we address the issue of surface states in GaN nanowire photoelectrodes by employing a simple and low-cost surface treatment method, which utilizes an organic thiol compound (i.e., 1,2-ethanedithiol). The surface-treated photocathode showed an enhanced photocurrent density of -31 mA/cm2 at -0.2 V versus RHE with an incident photon-to-current conversion efficiency of 18.3%, whereas untreated nanowires yielded only 8.1% efficiency. Furthermore, the surface passivation provides enhanced photoelectrochemical stability as surface-treated nanowires retained ∼80% of their initial photocurrent value and produced 8000 μmol of gas molecules over 55 h at acidic conditions (pH ∼ 0), whereas the untreated nanowires demonstrated only <4 h of photoelectrochemical stability. These findings shed new light on the importance of surface passivation of nanostructured photoelectrodes for photoelectrochemical applications.
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Affiliation(s)
- Purushothaman Varadhan
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Hui-Chun Fu
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Davide Priante
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Jose Ramon Duran Retamal
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Chao Zhao
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Mohamed Ebaid
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Tien Khee Ng
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Idirs Ajia
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Somak Mitra
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Iman S Roqan
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Boon S Ooi
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
| | - Jr-Hau He
- Electrical Engineering Program and ‡Materials Science and Engineering Program, King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia
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Ebaid M, Kang JH, Yoo YS, Lim SH, Cho YH, Ryu SW. Vertically aligned InGaN nanowires with engineered axial In composition for highly efficient visible light emission. Sci Rep 2015; 5:17003. [PMID: 26585509 PMCID: PMC4653627 DOI: 10.1038/srep17003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/22/2015] [Indexed: 11/23/2022] Open
Abstract
We report on the fabrication of novel InGaN nanowires (NWs) with improved crystalline quality and high radiative efficiency for applications as nanoscale visible light emitters. Pristine InGaN NWs grown under a uniform In/Ga molar flow ratio (UIF) exhibited multi-peak white-like emission and a high density of dislocation-like defects. A phase separation and broad emission with non-uniform luminescent clusters were also observed for a single UIF NW investigated by spatially resolved cathodoluminescence. Hence, we proposed a simple approach based on engineering the axial In content by increasing the In/Ga molar flow ratio at the end of NW growth. This new approach yielded samples with a high luminescence intensity, a narrow emission spectrum, and enhanced crystalline quality. Using time-resolved photoluminescence spectroscopy, the UIF NWs exhibited a long radiative recombination time (τr) and low internal quantum efficiency (IQE) due to strong exciton localization and carrier trapping in defect states. In contrast, NWs with engineered In content demonstrated three times higher IQE and a much shorter τr due to mitigated In fluctuation and improved crystal quality.
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Affiliation(s)
- Mohamed Ebaid
- Department of Physics, Chonnam National University, Gwangju 500-757, Republic of Korea.,Department of Physics, Faculty of Science, Beni-Suef University, Beni-Suef 62511, Egypt
| | - Jin-Ho Kang
- Department of Physics, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Yang-Seok Yoo
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Seung-Hyuk Lim
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Yong-Hoon Cho
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Sang-Wan Ryu
- Department of Physics, Chonnam National University, Gwangju 500-757, Republic of Korea
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AlOtaibi B, Fan S, Vanka S, Kibria MG, Mi Z. A Metal-Nitride Nanowire Dual-Photoelectrode Device for Unassisted Solar-to-Hydrogen Conversion under Parallel Illumination. NANO LETTERS 2015; 15:6821-6828. [PMID: 26360182 DOI: 10.1021/acs.nanolett.5b02671] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A dual-photoelectrode device, consisting of a photoanode and photocathode with complementary energy bandgaps, has long been perceived as an ideal scheme for achieving high efficiency, unassisted solar-driven water splitting. Previously reported 2-photon tandem devices, however, generally exhibit an extremely low efficiency (<0.1%), which has been largely limited by the incompatibility between the two photoelectrode materials. Here we show that the use of metal-nitride nanowire photoelectrodes, together with the scheme of parallel illumination by splitting the solar spectrum spatially and spectrally, can break the efficiency bottleneck of conventional 2-photon tandem devices. We have first investigated a dual-photoelectrode device consisting of a GaN nanowire photoanode and an InGaN nanowire photocathode, which exhibited an open circuit potential of 1.3 V and nearly 20-fold enhancement in the power conversion efficiency under visible light illumination (400-600 nm), compared to the individual photoelectrodes in 1 mol/L HBr. We have further demonstrated a dual-photoelectrode device consisting of parallel-connected metal-nitride nanowire photoanodes and a Si/InGaN nanowire photocathode, which can perform unassisted, direct solar-to-hydrogen conversion. A power conversion efficiency of 2% was measured under AM1.5G 1 sun illumination.
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Affiliation(s)
- B AlOtaibi
- Department of Electrical and Computer Engineering, McGill University 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - S Fan
- Department of Electrical and Computer Engineering, McGill University 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - S Vanka
- Department of Electrical and Computer Engineering, McGill University 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - M G Kibria
- Department of Electrical and Computer Engineering, McGill University 3480 University Street, Montreal, Quebec H3A 0E9, Canada
| | - Z Mi
- Department of Electrical and Computer Engineering, McGill University 3480 University Street, Montreal, Quebec H3A 0E9, Canada
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AlOtaibi B, Fan S, Wang D, Ye J, Mi Z. Wafer-Level Artificial Photosynthesis for CO2 Reduction into CH4 and CO Using GaN Nanowires. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00776] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bandar AlOtaibi
- Department
of Electrical and Computer Engineering, McGill University, 3480
University Street, Montreal, Quebec H3A 0E9, Canada
| | - Shizhao Fan
- Department
of Electrical and Computer Engineering, McGill University, 3480
University Street, Montreal, Quebec H3A 0E9, Canada
| | - Defa Wang
- TU-NIMS
Joint Research Center, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
- Collaborative Innovation
Center of Chemical Science and Engineering (Tianjin), 92 Weijin Road, Nankai District, Tianjin 300072, China
| | - Jinhua Ye
- TU-NIMS
Joint Research Center, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China
- International
Center for Materials Nanoarchitectonics (WPI-MANA) and Environmental
Remediation Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan
| | - Zetian Mi
- Department
of Electrical and Computer Engineering, McGill University, 3480
University Street, Montreal, Quebec H3A 0E9, Canada
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