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Xie L, Liang C, Wu Y, Wang K, Hou W, Guo H, Wang Z, Lam YM, Liu Z, Wang L. Isomerization Engineering of Oxygen-Enriched Carbon Quantum Dots for Efficient Electrochemical Hydrogen Peroxide Production. Small 2024:e2401253. [PMID: 38713154 DOI: 10.1002/smll.202401253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/26/2024] [Indexed: 05/08/2024]
Abstract
Hydrogen peroxide (H2O2) has emerged as a kind of multi-functional green oxidants with extensive industrial utility. Oxidized carbon materials exhibit promises as electrocatalysts in the two-electron (2e-) oxygen reduction reaction (ORR) for H2O2 production. However, the precise identification and fabrication of active sites that selectively yield H2O2 present a serious challenge. Herein, a structural engineering strategy is employed to synthesize oxygen-doped carbon quantum dots (o-CQD) for the 2e- ORR. The surface electronic structure of the o-CQDs is systematically modulated by varying isomerization precursors, thereby demonstrating excellent electrocatalyst performance. Notably, o-CQD-3 emerges as the most promising candidate, showcasing a remarkable H2O2 selectivity of 96.2% (n = 2.07) at 0.68 V versus RHE, coupled with a low Tafel diagram of 66.95 mV dec-1. In the flow cell configuration, o-CQD-3 achieves a H2O2 productivity of 338.7 mmol gcatalyst -1 h-1, maintaining consistent production stability over an impressive 120-hour duration. Utilizing in situ technology and density functional theory calculations, it is unveil that edge sites of o-CQD-3 are facilely functionalized by C-O-C groups under alkaline ORR conditions. This isomerization engineering approach advances the forefront of sustainable catalysis and provides a profound insight into the carbon-based catalyst design for environmental-friendly chemical synthesis processes.
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Affiliation(s)
- Leping Xie
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, BaoShan District, Shanghai, 200444, P. R. China
| | - Caihong Liang
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yao Wu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Kang Wang
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, BaoShan District, Shanghai, 200444, P. R. China
| | - Weidong Hou
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, BaoShan District, Shanghai, 200444, P. R. China
| | - Huazhang Guo
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, BaoShan District, Shanghai, 200444, P. R. China
| | - Zeming Wang
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, BaoShan District, Shanghai, 200444, P. R. China
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zheng Liu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Liang Wang
- Institute of Nanochemistry and Nanobiology, School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, BaoShan District, Shanghai, 200444, P. R. China
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2
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Liang C, Yen Z, Salim T, Lam YM. Elucidation of the synergistic effects of 3d metal (M = Cu, Co, and Ni) dopants and terminations (T = -O- and -OH) of Ti 3C 2T x MXenes for urea adsorption ability via DFT calculations and experiments. Phys Chem Chem Phys 2023; 25:31874-31883. [PMID: 37971384 DOI: 10.1039/d3cp03263a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Dialysis is an artificial process to remove excess urea toxins from the body through adsorption or conversion. Urea adsorption by emergent 2D materials such as MXenes is one probable approach. Based on density functional theory (DFT) studies, the surface of Ti3C2Tx (T = -O- and -OH) MXenes is not optimum for urea adsorption. Therefore, functionalization with 3d metal dopants (Cu, Co, and Ni) is proposed to improve their urea adsorption ability. DFT calculations indicate that oxygen-terminated Ti3C2O2 has a much better urea adsorption ability when doped with Cu, Co, and Ni, with adsorption energy (Eads) values of -2.11 eV, -1.90 eV and -1.72 eV, respectively. These adsorption energies are much more favourable than that of the undoped one (Eads = -0.52 eV). To verify the calculation results, MILD Ti3C2Tx, or MXenes synthesized via the safer and easier minimally intensive layer delamination (MILD) method, were utilized to simulate Ti3C2O2 since they have -O- termination as the dominant species. Experimentally, the adsorption studies found that low concentration of Cu, Co, and Ni on MILD Ti3C2Tx showed a urea removal efficiency of 21.9%, 6.0% and 0.2%, respectively, much better than 0% removal efficiency of unfunctionalized Ti3C2Tx. Therefore, both DFT calculations and experiments showed that various metal functionalized MXenes have a similar trend for urea adsorption, highlighting the feasibility of using the computational approach to predict urea adsorption and further opening a new promising direction for the urea adsorption. Finally, this study is also the first to examine synergistic effects of metal dopants and surface terminations on MXenes for urea adsorption.
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Affiliation(s)
- Caihong Liang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
| | - Zhihao Yen
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
- Facility for Analysis, Characterization, Testing and Simulation (FACTS), Nanyang Technological University, Singapore, 639798, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
- Facility for Analysis, Characterization, Testing and Simulation (FACTS), Nanyang Technological University, Singapore, 639798, Singapore
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3
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Sana B, Ding K, Siau JW, Pasula RR, Chee S, Kharel S, Lena JBH, Goh E, Rajamani L, Lam YM, Lim S, Ghadessy JF. Thermostability enhancement of polyethylene terephthalate degrading PETase using self- and nonself-ligating protein scaffolding approaches. Biotechnol Bioeng 2023; 120:3200-3209. [PMID: 37555384 DOI: 10.1002/bit.28523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 08/10/2023]
Abstract
Polyethylene terephthalate (PET) hydrolase enzymes show promise for enzymatic PET degradation and green recycling of single-use PET vessels representing a major source of global pollution. Their full potential can be unlocked with enzyme engineering to render activities on recalcitrant PET substrates commensurate with cost-effective recycling at scale. Thermostability is a highly desirable property in industrial enzymes, often imparting increased robustness and significantly reducing quantities required. To date, most engineered PET hydrolases show improved thermostability over their parental enzymes. Here, we report engineered thermostable variants of Ideonella sakaiensis PET hydrolase enzyme (IsPETase) developed using two scaffolding strategies. The first employed SpyCatcher-SpyTag technology to covalently cyclize IsPETase, resulting in increased thermostability that was concomitant with reduced turnover of PET substrates compared to native IsPETase. The second approach using a GFP-nanobody fusion protein (vGFP) as a scaffold yielded a construct with a melting temperature of 80°C. This was further increased to 85°C when a thermostable PETase variant (FAST PETase) was scaffolded into vGFP, the highest reported so far for an engineered PET hydrolase derived from IsPETase. Thermostability enhancement using the vGFP scaffold did not compromise activity on PET compared to IsPETase. These contrasting results highlight potential topological and dynamic constraints imposed by scaffold choice as determinants of enzyme activity.
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Affiliation(s)
- Barindra Sana
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Ke Ding
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Jia Wei Siau
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Rupali Reddy Pasula
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological Univeristy, Singapore, Singapore
| | - Sharon Chee
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Sharad Kharel
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jean-Baptise Henri Lena
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Eunice Goh
- Singapore Eye Research Institute, The Academia, Singapore, Singapore
| | | | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Sierin Lim
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological Univeristy, Singapore, Singapore
| | - John F Ghadessy
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
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Li Y, Hu H, Salim T, Cheng G, Lam YM, Ding J. Flexible Wet-Spun PEDOT:PSS Microfibers Integrating Thermal-Sensing and Joule Heating Functions for Smart Textiles. Polymers (Basel) 2023; 15:3432. [PMID: 37631489 PMCID: PMC10457801 DOI: 10.3390/polym15163432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/13/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Multifunctional fiber materials play a key role in the field of smart textiles. Temperature sensing and active thermal management are two important functions of smart fabrics, but few studies have combined both functions in a single fiber material. In this work, we demonstrate a temperature-sensing and in situ heating functionalized conductive polymer microfiber by exploiting its high electrical conductivity and thermoelectric properties. The conductive polymer microfibers were prepared by wet-spinning the PEDOT:PSS aqueous dispersion with ionic liquid additives, which was used to enhance the electrical and mechanical properties of the final microfibers. The thermoelectric properties of these microfibers were further studied. Due to their excellent flexibility and mechanical properties, these fibers can be easily integrated into commercial fabrics for the manufacture of smart textiles through knitting. We further demonstrated a smart glove with integrated temperature-sensing and in situ heating functions, and further explored thermoelectric fiber-based temperature-sensing array fabric. These works combine the thermoelectric properties and heating function of conductive polymer fibers, providing new insights that enable further development of high-performance, multifunctional wearable smart textiles.
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Affiliation(s)
- Yan Li
- School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China;
| | - Hongwei Hu
- Institute of Intelligent Flexible Mechatronics, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China;
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore; (T.S.); (Y.M.L.)
| | - Guanggui Cheng
- Institute of Intelligent Flexible Mechatronics, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China;
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore; (T.S.); (Y.M.L.)
| | - Jianning Ding
- Institute of Intelligent Flexible Mechatronics, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China;
- School of Mechanical Engineering, Yangzhou University, Yangzhou 225009, China
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5
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Yuan Z, Zhang M, Yen Z, Feng M, Jin X, Ibrahim A, Ahmed MG, Salim T, Gonçalves RA, Sum TC, Lam YM, Wong LH. High-Performance Semi-Transparent Perovskite Solar Cells with over 22% Visible Transparency: Pushing the Limit through MXene Interface Engineering. ACS Appl Mater Interfaces 2023; 15:37629-37639. [PMID: 37463286 DOI: 10.1021/acsami.3c03804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
Semi-transparent perovskite solar cells (ST-PSCs) have attracted enormous attention recently due to their potential in building-integrated photovoltaic. To obtain adequate average visible transmittance (AVT), a thin perovskite is commonly employed in ST-PSCs. While the thinner perovskite layer has higher transparency, its light absorption efficiency is reduced, and the device shows lower power conversion efficiency (PCE). In this work, a combination of high-quality transparent conducting layers and surface engineering using 2D-MXene results in a superior PCE. In situ high-temperature X-ray diffraction provides direct evidence that the MXene interlayer retards the perovskite crystallization process and leads to larger perovskite grains with fewer grain boundaries, which are favorable for carrier transport. The interfacial carrier recombination is decreased due to fewer defects in the perovskite. Consequently, the current density of the devices with MXene increased significantly. Also, optimized indium tin oxide provides appreciable transparency and conductivity as the top electrode. The semi-transparent device with a PCE of 14.78% and AVT of over 26.7% (400-800 nm) was successfully obtained, outperforming most reported ST-PSCs. The unencapsulated device maintained 85.58% of its original efficiency after over 1000 h under ambient conditions. This work provides a new strategy to prepare high-efficiency ST-PSCs with remarkable AVT and extended stability.
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Affiliation(s)
- Zhengtian Yuan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), Nanomaterials for Energy and Energy-Water Nexus (NEW), Campus for Research Excellence and Technological Enterprise (CREATE), Singapore 138602, Singapore
| | - Mengyuan Zhang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Zhihao Yen
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Minjun Feng
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Xin Jin
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Ahmad Ibrahim
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Mahmoud G Ahmed
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Rui A Gonçalves
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Tze Chien Sum
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Lydia H Wong
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Singapore-HUJ Alliance for Research and Enterprise (SHARE), Nanomaterials for Energy and Energy-Water Nexus (NEW), Campus for Research Excellence and Technological Enterprise (CREATE), Singapore 138602, Singapore
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6
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Xiao X, Cheng L, Bao D, Tan QY, Salim T, Soci C, Chia EEM, Lam YM. Unveiling Charge-Transfer Dynamics at Singlet Fission Layer/Hybrid Perovskite Interface. ACS Appl Mater Interfaces 2023; 15:38049-38055. [PMID: 37493635 DOI: 10.1021/acsami.3c06933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Singlet fission (SF) materials have been applied in various types of solar cells to pursue higher power conversion efficiency (PCE) beyond the Shockley-Queisser (SQ) limit. SF implementation in perovskite solar cells has not been successfully realized yet due to the insufficient understanding of the SF/perovskite heterojunctions. In this work, we attempt to elucidate the charge dynamics of an SF/perovskite system by incorporating a well-known SF molecule, TIPS-pentacene, and a triple-cation perovskite Cs0.05(FA0.85MA0.15)0.95PbI2.55Br0.45, owing to their well-matched energy structures. The transient absorption spectra and kinetic fitting plots suggest an electron-transfer process from the triplet state of TIPS-pentacene to perovskite in the picosecond regime, which increases the carrier density by 20% in the perovskite layer. This work confirms the existence of an electron-transfer process between the SF material and perovskite, providing a pathway to SF-enhanced perovskite solar cells.
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Affiliation(s)
- Xingchi Xiao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Liang Cheng
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, China
| | - Di Bao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Qi Ying Tan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Facility for Analysis Characterisation Testing and Simulation (FACTS), Nanyang Technological University, Singapore 639798, Singapore
| | - Cesare Soci
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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7
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Sharma R, Zhang Q, Nguyen LL, Salim T, Lam YM, Sum TC, Duchamp M. Effect of Air Exposure on Electron-Beam-Induced Degradation of Perovskite Films. ACS Nanosci Au 2023; 3:230-240. [PMID: 37360848 PMCID: PMC10288607 DOI: 10.1021/acsnanoscienceau.2c00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 06/28/2023]
Abstract
Organic-inorganic halide perovskites are interesting candidates for solar cell and optoelectronic applications owing to their advantageous properties such as a tunable band gap, low material cost, and high charge carrier mobilities. Despite making significant progress, concerns about material stability continue to impede the commercialization of perovskite-based technology. In this article, we investigate the impact of environmental parameters on the alteration of structural properties of MAPbI3 (CH3NH3PbI3) thin films using microscopy techniques. These characterizations are performed on MAPbI3 thin films exposed to air, nitrogen, and vacuum environments, the latter being possible by using dedicated air-free transfer setups, after their fabrication into a nitrogen-filled glovebox. We observed that even less than 3 min of air exposure increases the sensitivity to electron beam deterioration and modifies the structural transformation pathway as compared to MAPbI3 thin films which are not exposed to air. Similarly, the time evolution of the optical responses and the defect formation of both air-exposed and non-air-exposed MAPbI3 thin films are measured by time-resolved photoluminescence. The formation of defects in the air-exposed MAPbI3 thin films is first observed by optical techniques at longer timescales, while structural modifications are observed by transmission electron microscopy (TEM) measurements and supported by X-ray photoelectron spectroscopy (XPS) measurements. Based on the complementarity of TEM, XPS, and time-resolved optical measurements, we propose two different degradation mechanism pathways for air-exposed and non-air-exposed MAPbI3 thin films. We find that when exposed to air, the crystalline structure of MAPbI3 shows gradual evolution from its initial tetragonal MAPbI3 structure to PbI2 through three different stages. No significant structural changes over time from the initial structure are observed for the MAPbI3 thin films which are not exposed to air.
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Affiliation(s)
- Romika Sharma
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
| | - Qiannan Zhang
- School
of Physical and Mathematical Sciences, Nanyang
Technological University, Singapore 637371, Singapore
| | - Linh Lan Nguyen
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
| | - Teddy Salim
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
| | - Yeng Ming Lam
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
| | - Tze Chien Sum
- School
of Physical and Mathematical Sciences, Nanyang
Technological University, Singapore 637371, Singapore
| | - Martial Duchamp
- School
of Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
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Yang F, Liang C, Zhou W, Zhao W, Li P, Hua Z, Yu H, Chen S, Deng S, Li J, Lam YM, Wang J. Oxide-Derived Bismuth as an Efficient Catalyst for Electrochemical Reduction of Flue Gas. Small 2023:e2300417. [PMID: 37026664 DOI: 10.1002/smll.202300417] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/06/2023] [Indexed: 06/19/2023]
Abstract
Post-combustion flue gas (mainly containing 5-40% CO2 balanced by N2 ) accounts for about 60% global CO2 emission. Rational conversion of flue gas into value-added chemicals is still a formidable challenge. Herein, this work reports a β-Bi2 O3 -derived bismuth (OD-Bi) catalyst with surface coordinated oxygen for efficient electroreduction of pure CO2 , N2, and flue gas. During pure CO2 electroreduction, the maximum Faradaic efficiency (FE) of formate reaches 98.0% and stays above 90% in a broad potential of 600 mV with a long-term stability of 50 h. Additionally, OD-Bi achieves an ammonia (NH3 ) FE of 18.53% and yield rate of 11.5 µg h-1 mgcat -1 in pure N2 atmosphere. Noticeably, in simulated flue gas (15% CO2 balanced by N2 with trace impurities), a maximum formate FE of 97.3% is delivered within a flow cell, meanwhile above 90% formate FEs are obtained in a wide potential range of 700 mV. In-situ Raman combined with theory calculations reveals that the surface coordinated oxygen species in OD-Bi can drastically activate CO2 and N2 molecules by selectively favors the adsorption of *OCHO and *NNH intermediates, respectively. This work provides a surface oxygen modulation strategy to develop efficient bismuth-based electrocatalysts for directly reducing commercially relevant flue gas into valuable chemicals.
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Affiliation(s)
- Fangqi Yang
- School of Chemistry and Chemical Engineering, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
- School of Materials Science and Engineering, Nanjing University of Posts and Telecommunications, No. 9 Wenyuan Road, Nanjing, 210023, China
| | - Caihong Liang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798
| | - Weizhen Zhou
- School of Chemistry and Chemical Engineering, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
| | - Wendi Zhao
- School of Resources and Environment, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
| | - Pengfei Li
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543
| | - Zhengyu Hua
- School of Chemistry and Chemical Engineering, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
| | - Haoming Yu
- School of Chemistry and Chemical Engineering, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
| | - Shixia Chen
- School of Chemistry and Chemical Engineering, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
| | - Shuguang Deng
- School for Engineering of Matter, Transport and Energy, Arizona State University, 551 E. Tyler Mall, Tempe, AZ, 85287, USA
| | - Jing Li
- School of Chemistry, Beihang University, Beijing, 100191, China
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, Singapore, 639798
| | - Jun Wang
- School of Chemistry and Chemical Engineering, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, China
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Li Y, Tiwari AK, Ng JS, Seah GL, Lim HK, Suteewong T, Tay CY, Lam YM, Tan KW. One-Pot Synthesis of Aminated Bimodal Mesoporous Silica Nanoparticles as Silver-Embedded Antibacterial Nanocarriers and CO 2 Capture Sorbents. ACS Appl Mater Interfaces 2022; 14:52279-52288. [PMID: 36375117 DOI: 10.1021/acsami.2c13076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Mesoporous silica nanoparticles have highly versatile structural properties that are suitable for a plethora of applications including catalysis, separation, and nanotherapeutics. We report a one-pot synthesis strategy that generates bimodal mesoporous silica nanoparticles via coassembly of a structure-directing Gemini surfactant (C16-3-16) with a tetraethoxysilane/(3-aminopropyl)triethoxysilane-derived sol additive. Synthesis temperature enables control of the nanoparticle shape, structure, and mesopore architecture. Variations of the aminosilane/alkylsilane molar ratio further enable programmable adjustments of hollow to core-shell and dense nanoparticle morphologies, bimodal pore sizes, and surface chemistries. The resulting Gemini-directed aminated mesoporous silica nanoparticles have excellent carbon dioxide adsorption capacities and antimicrobial properties against Escherichia coli. Our results provide an enhanced understanding of the structure formation of multiscale mesoporous inorganic materials that are desirable for numerous applications such as carbon sequestration, water remediation, and biomedical-related applications.
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Affiliation(s)
- Yun Li
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Amit Kumar Tiwari
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Jingyi Sandy Ng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Geok Leng Seah
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Hong Kit Lim
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Teeraporn Suteewong
- Department of Chemical Engineering, School of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand
| | - Chor Yong Tay
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Kwan W Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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10
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Yang F, Liang C, Yu H, Zeng Z, Lam YM, Deng S, Wang J. Phosphorus-Doped Graphene Aerogel as Self-Supported Electrocatalyst for CO 2 -to-Ethanol Conversion. Adv Sci (Weinh) 2022; 9:e2202006. [PMID: 35821388 PMCID: PMC9443446 DOI: 10.1002/advs.202202006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Electrochemical reduction of carbon dioxide (CO2 ) to ethanol is a promising strategy for global warming mitigation and resource utilization. However, due to the intricacy of C─C coupling and multiple proton-electron transfers, CO2 -to-ethanol conversion remains a great challenge with low activity and selectivity. Herein, it is reported a P-doped graphene aerogel as a self-supporting electrocatalyst for CO2 reduction to ethanol. High ethanol Faradaic efficiency (FE) of 48.7% and long stability of 70 h are achieved at -0.8 VRHE . Meanwhile, an outstanding ethanol yield of 14.62 µmol h-1 cm-2 can be obtained, outperforming most reported electrocatalysts. In situ Raman spectra indicate the important role of adsorbed *CO intermediates in CO2 -to-ethanol conversion. Furthermore, the possible active sites and optimal pathway for ethanol formation are revealed by density functional theory calculations. The graphene zigzag edges with P doping enhance the adsorption of *CO intermediate and increase the coverage of *CO on the catalyst surface, which facilitates the *CO dimerization and boosts the EtOH formation. In addition, the hierarchical pore structure of P-doped graphene aerogels exposes abundant active sites and facilitates mass/charge transfer. This work provides inventive insight into designing metal-free catalysts for liquid products from CO2 electroreduction.
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Affiliation(s)
- Fangqi Yang
- School of Resource and EnvironmentNanchang UniversityNo. 999 Xuefu AvenueJiangxi330031P. R. China
- Chemistry and Chemical Engineering SchoolNanchang UniversityNo. 999 Xuefu AvenueJiangxi330031P. R. China
- Department of ChemistryNational University of Singapore3 Science Drive 3Singapore117543Singapore
| | - Caihong Liang
- School of Materials Science and EngineeringNanyang Technological UniversitySingapore639798Singapore
| | - Haoming Yu
- Chemistry and Chemical Engineering SchoolNanchang UniversityNo. 999 Xuefu AvenueJiangxi330031P. R. China
| | - Zheling Zeng
- Chemistry and Chemical Engineering SchoolNanchang UniversityNo. 999 Xuefu AvenueJiangxi330031P. R. China
| | - Yeng Ming Lam
- School of Materials Science and EngineeringNanyang Technological UniversitySingapore639798Singapore
- Facility for AnalysisCharacterizationTesting and Simulation (FACTS)Nanyang Technological UniversitySingapore639798Singapore
| | - Shuguang Deng
- School for Engineering of MatterTransport and EnergyArizona State University551 E. Tyler MallTempeAZ85287USA
| | - Jun Wang
- Chemistry and Chemical Engineering SchoolNanchang UniversityNo. 999 Xuefu AvenueJiangxi330031P. R. China
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11
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Abstract
Scarcity of natural resources, shifting demographics, climate change, and increasing waste are four major challenges in the quest to feed the exploding world population. These challenges serve as the impetus to harness novel technologies to improve agriculture, productivity, and sustainability. Urban farming has several advantages over conventional farming: higher productivity, improved sustainability, and the ability to provide fresh food all year round. Novel materials are key to accelerating the evolution of urban farming - with their ability to facilitate controlled release of nutrients and pesticides, improved seed health, substrates with better water retention capability, more efficient recycling of agricultural waste, and precise plant health monitoring. Materials science enables environmental sustainability and higher harvest yields in urban farms. Here, Singapore is used as an example of a land-scarce city where urban farming may be the solution for future food production. Potential research directions and challenges in urban farming are highlighted, and how material optimization and innovation drive the development of urban farming to meet national and global food demands is briefly discussed. This review serves as a guide for researchers and a reference for stakeholders of urban farms, policy makers, and other interested parties.
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Affiliation(s)
- Lifei Xi
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, Singapore, 639798, Singapore
| | - Mengyuan Zhang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Liling Zhang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Tedrick T S Lew
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, 138634, Singapore
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117585, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, Singapore, 639798, Singapore
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12
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Wang Y, Tan SN, Mohd Yusof ML, Ghosh S, Lam YM. Assessment of heavy metal and metalloid levels and screening potential of tropical plant species for phytoremediation in Singapore. Environ Pollut 2022; 295:118681. [PMID: 34933060 DOI: 10.1016/j.envpol.2021.118681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 12/01/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
Heavy metal or metalloid contamination is a common problem in soils of urban environments. Their introduction can be due to unpremeditated anthropogenic activities like atmospheric deposition produced by diffuse sources, construction activities and landscape maintenance. Phytoremediation is a rapidly evolving, sustainable approach to remediate the contaminated lands where metals and metalloids are highly persistent in the environment. The present work sets out to determine the level of 12 heavy metals and metalloids (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb and Zn) in soil and their accumulation by plant foliage found in nature parks and industrial sites in Singapore. The latter also involve the investigation of the remediation capacity of selected tropical plant species found at the sampling sites. The study is done using digestion and inductively coupled plasma-optical emission spectrometry. Eleven soil sampling sites across Singapore with 300 sampling points were selected, where soil (0-10 cm) and plant foliage samples were collected. Bioconcentration factors were determined to assess the phytoremediation potential of the collected plant species. Toxicity risk of heavy metals were assessed by comparing the target and intervention values from the soil quality guidelines by the Dutch Standard. Results of the study revealed there were regions where levels of heavy metals and metalloids were relatively high and could affect the environment and the health of flora and fauna in Singapore. Our study discovered that there were available tropical plant species (e.g., wildflowers, ferns and shrubs) which could potentially play a significant role in the remediation of contaminated lands that could open up a huge possibility of developing a sustainable and environmentally-friendly way of managing this emerging urban problem. Results showed that 12 plant species, including hyperaccumulator like Pteris vittata, Centella asiatica, were effective for the accumulation of heavy metals and metalloids.
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Affiliation(s)
- Yamin Wang
- School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore
| | - Swee Ngin Tan
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 637616, Singapore
| | | | - Subhadip Ghosh
- Centre for Urban Greenery and Ecology, National Parks Board, 259569, Singapore; School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore.
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13
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Ying Y, Zhang Z, Peh SB, Karmakar A, Cheng Y, Zhang J, Xi L, Boothroyd C, Lam YM, Zhong C, Zhao D. Innenrücktitelbild: Pressure‐Responsive Two‐Dimensional Metal–Organic Framework Composite Membranes for CO
2
Separation (Angew. Chem. 20/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yunpan Ying
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Zhengqing Zhang
- State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin 300387 China
| | - Shing Bo Peh
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Avishek Karmakar
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Youdong Cheng
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Jian Zhang
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Lifei Xi
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Chris Boothroyd
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Yeng Ming Lam
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Chongli Zhong
- State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin 300387 China
| | - Dan Zhao
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
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14
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Ying Y, Zhang Z, Peh SB, Karmakar A, Cheng Y, Zhang J, Xi L, Boothroyd C, Lam YM, Zhong C, Zhao D. Inside Back Cover: Pressure‐Responsive Two‐Dimensional Metal–Organic Framework Composite Membranes for CO
2
Separation (Angew. Chem. Int. Ed. 20/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/anie.202103672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yunpan Ying
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Zhengqing Zhang
- State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin 300387 China
| | - Shing Bo Peh
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Avishek Karmakar
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Youdong Cheng
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Jian Zhang
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Lifei Xi
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Chris Boothroyd
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Yeng Ming Lam
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Chongli Zhong
- State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin 300387 China
| | - Dan Zhao
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
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15
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Ying Y, Zhang Z, Peh SB, Karmakar A, Cheng Y, Zhang J, Xi L, Boothroyd C, Lam YM, Zhong C, Zhao D. Pressure-Responsive Two-Dimensional Metal-Organic Framework Composite Membranes for CO 2 Separation. Angew Chem Int Ed Engl 2021; 60:11318-11325. [PMID: 33599088 DOI: 10.1002/anie.202017089] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/13/2021] [Indexed: 11/06/2022]
Abstract
The regulation of permeance and selectivity in membrane systems may allow effective relief of conventional energy-intensive separations. Here, pressure-responsive ultrathin membranes (≈100 nm) fabricated by compositing flexible two-dimensional metal-organic framework nanosheets (MONs) with graphene oxide nanosheets for CO2 separation are reported. By controlling the gas permeation direction to leverage the pressure-responsive phase transition of the MONs, CO2 -induced gate opening and closing behaviors are observed in the resultant membranes, which are accompanied with the sharp increase of CO2 permeance (from 173.8 to 1144 gas permeation units) as well as CO2 /N2 and CO2 /CH4 selectivities (from 4.1 to 22.8 and from 4 to 19.6, respectively). The flexible behaviors and separation mechanism are further elucidated by molecular dynamics simulations. This work establishes the relevance of structural transformation-based framework dynamics chemistry in smart membrane systems.
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Affiliation(s)
- Yunpan Ying
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
| | - Zhengqing Zhang
- State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin, 300387, China
| | - Shing Bo Peh
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
| | - Avishek Karmakar
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
| | - Youdong Cheng
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
| | - Jian Zhang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
| | - Lifei Xi
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore, Singapore
| | - Chris Boothroyd
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore, Singapore
| | - Yeng Ming Lam
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS), Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore, Singapore
| | - Chongli Zhong
- State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin, 300387, China
| | - Dan Zhao
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore, Singapore
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16
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Ying Y, Zhang Z, Peh SB, Karmakar A, Cheng Y, Zhang J, Xi L, Boothroyd C, Lam YM, Zhong C, Zhao D. Pressure‐Responsive Two‐Dimensional Metal–Organic Framework Composite Membranes for CO
2
Separation. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202017089] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yunpan Ying
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Zhengqing Zhang
- State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin 300387 China
| | - Shing Bo Peh
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Avishek Karmakar
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Youdong Cheng
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Jian Zhang
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
| | - Lifei Xi
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Chris Boothroyd
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Yeng Ming Lam
- Facility for Analysis, Characterisation, Testing and Simulation (FACTS) Nanyang Technological University 50 Nanyang Avenue 639798 Singapore Singapore
| | - Chongli Zhong
- State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin 300387 China
| | - Dan Zhao
- Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117585 Singapore Singapore
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17
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Duchamp M, Hu H, Lam YM, Dunin-Borkowski RE, Boothroyd CB. STEM electron beam-induced current measurements of organic-inorganic perovskite solar cells. Ultramicroscopy 2020; 217:113047. [PMID: 32623204 DOI: 10.1016/j.ultramic.2020.113047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 03/27/2020] [Accepted: 06/05/2020] [Indexed: 10/24/2022]
Abstract
We describe a new approach for preparing organic-inorganic perovskite solar cells for electron beam-induced current (EBIC) measurements in plan-view geometry. This method substantially reduces sample preparation artefacts, provides good electrical contact and keeps the preparation steps as close as possible to those for real devices. Our EBIC images were acquired simultaneously with annular dark-field scanning transmission electron microscopy images using a home-made highly sensitive EBIC amplifier. High-angle annular dark-field images and energy dispersive X-ray maps were recorded from the same area immediately afterwards. This allowed the EBIC contrast to be correlated with regions containing N and a deficiency of O. The EBIC contrast was also found to be similar to secondary electron contrast recorded with a scanning electron microscope. By identifying the generation and absorption electron processes, we determine that EBIC cannot be separated from the secondary electron and absorbed currents. This means that careful analysis needs to be performed before conclusions can be made on the origin of the current measured across p-n or p-i-n junctions.
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Affiliation(s)
- M Duchamp
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore; Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, Jülich, 52425, Germany.
| | - H Hu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
| | - Y M Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore
| | - R E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, Jülich, 52425, Germany
| | - C B Boothroyd
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Technological University, Singapore 639798, Singapore; Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, Jülich, 52425, Germany
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18
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Ye S, Chen B, Cheng Y, Feng M, Rao H, Lam YM, Sum TC. Resolving Spectral Mismatch Errors for Perovskite Solar Cells in Commercial Class AAA Solar Simulators. J Phys Chem Lett 2020; 11:3782-3788. [PMID: 32434335 DOI: 10.1021/acs.jpclett.0c00355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Senyun Ye
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Bingbing Chen
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
| | - Yuanhang Cheng
- Solar Energy Research Institute of Singapore, National University of Singapore, 117574, Singapore
| | - Minjun Feng
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
| | - Haixia Rao
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link 637371, Singapore
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19
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Man Z, Li P, Zhou D, Wang Y, Liang X, Zang R, Li P, Zuo Y, Lam YM, Wang G. Two Birds with One Stone: FeS 2@C Yolk-Shell Composite for High-Performance Sodium-Ion Energy Storage and Electromagnetic Wave Absorption. Nano Lett 2020; 20:3769-3777. [PMID: 32255351 DOI: 10.1021/acs.nanolett.0c00789] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cost-effective material with a rational design is significant for both sodium-ion batteries (SIBs) and electromagnetic wave (EMW) absorption. Herein, we report an elaborate yolk-shell FeS2@C nanocomposite as a promising material for application in both SIBs and EMW absorption. When applied as an anode material in SIBs, the yolk-shell structure not only facilitates a fast electron transport and shortens Na ion diffusion paths but also eases the huge volume change of FeS2 during repeated discharge/charge processes. The as-developed FeS2@C exhibits a high specific capacity of 616 mA h g-1 after 100 cycles at 0.1 A g-1 with excellent rate performance. Furthermore, owing to the significant cavity and interfacial effects enabled by yolk-shell structuring, the FeS2@C nanocomposite delivers excellent EMW absorption properties with a strong reflection loss (-45 dB with 1.45 mm matching thickness) and a broad 15.4 GHz bandwidth. This work inspires the development of high-performance bifunctional materials.
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Affiliation(s)
- Zengming Man
- College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Peng Li
- College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Dong Zhou
- Centre for Clean Energy Technology, Faculty of Science, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Yizhou Wang
- Centre for Clean Energy Technology, Faculty of Science, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Xiaohui Liang
- College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Rui Zang
- College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Pengxin Li
- College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yuqi Zuo
- College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Guoxiu Wang
- Centre for Clean Energy Technology, Faculty of Science, University of Technology Sydney, Sydney, New South Wales 2007, Australia
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20
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Gonçalves RA, Naidjonoka P, Nylander T, Miguel MG, Lindman B, Lam YM. Facile control of surfactant lamellar phase transition and adsorption behavior. RSC Adv 2020; 10:18025-18034. [PMID: 35517209 PMCID: PMC9053641 DOI: 10.1039/d0ra01340d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/08/2020] [Indexed: 11/21/2022] Open
Abstract
This study sets out to investigate the effect of the presence of small water-soluble additives on the tunability of the surfactant gel-to-liquid crystalline (Lβ-Lα) phase transition temperature (T m) for a bilayer-forming cationic surfactant and the phase behavior of such surfactant systems on dilution. This is strongly driven by the fact that this type of cationic surfactant has many interesting unanswered scientific questions and has found applications in various areas such as consumer care, the petrochemical industry, food science, etc. The underlying surfactant/additive interactions and the interfacial behavior of lamellar surfactant systems including the surfactant deposition on surfaces can provide new avenues to develop novel product formulations. We have examined dioctadecyldimethyl ammonium chloride (DODAC) in the presence of small polar additives, with respect to the phase behavior upon dilution and the deposition on silica. Differential scanning calorimetry (DSC) is used to track the transition temperature, T m, and synchrotron and laboratory-based small and wide-angle X-ray scattering (SAXS and WAXS) were used to determine the self-assembled surfactant structure below and above the T m. DSC scans showed that upon dilution the additives could be removed from the surfactant bilayer which in turn tuned the T m. A spontaneous transition from a liquid crystalline (Lα) phase to a gel (Lβ) phase on dilution was demonstrated, which indicated that additives could be taken out from the Lα phase. By means of in situ null ellipsometry, the deposition of a diluted surfactant Lβ phase upon replacement of bulk solution by deionized water was followed. This technique enables time-resolved monitoring of the deposited surfactant layer thickness and adsorbed amount, which allows us to understand the deposition on surfaces. Robust layers at least one bilayer-thick were deposited onto the surface and shown to be irreversibly adsorbed due to poor surfactant solvency in water. The thickest layer of surfactant deposited after dilution was found for mixtures with small amounts of additive since high amounts might lead to a phase-separated system.
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Affiliation(s)
- Rui A Gonçalves
- School of Materials Science and Engineering, Nanyang Technological University 639798 Singapore Singapore
| | - Polina Naidjonoka
- Division of Physical Chemistry, Department of Chemistry, Centre for Chemistry and Chemical Engineering, Lund University SE-221 00 Lund Sweden
| | - Tommy Nylander
- Division of Physical Chemistry, Department of Chemistry, Centre for Chemistry and Chemical Engineering, Lund University SE-221 00 Lund Sweden
| | - Maria G Miguel
- Department of Chemistry, University of Coimbra 3004-535 Coimbra Portugal
| | - Björn Lindman
- School of Materials Science and Engineering, Nanyang Technological University 639798 Singapore Singapore .,Division of Physical Chemistry, Department of Chemistry, Centre for Chemistry and Chemical Engineering, Lund University SE-221 00 Lund Sweden
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University 639798 Singapore Singapore
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21
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Leung SL, Ho MK, Lam YM, Chow HY, So YH, Leung YC. PEGylated recombinant human arginase as a drug for breast cancer. Hong Kong Med J 2019; 25 Suppl 9:28-31. [PMID: 31889032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023] Open
Affiliation(s)
- S L Leung
- Department of Applied Biology and Chemical Technology, and Lo Ka Chung Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University
| | - M K Ho
- Department of Applied Biology and Chemical Technology, and Lo Ka Chung Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University
| | - Y M Lam
- Department of Applied Biology and Chemical Technology, and Lo Ka Chung Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University
| | - H Y Chow
- Department of Applied Biology and Chemical Technology, and Lo Ka Chung Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University
| | - Y H So
- Department of Applied Biology and Chemical Technology, and Lo Ka Chung Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University
| | - Y C Leung
- Department of Applied Biology and Chemical Technology, and Lo Ka Chung Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University
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22
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Liu W, Shaikh DB, Rao PS, Bhosale RS, Said AA, Mak AM, Wang Z, Zhao M, Gao W, Chen B, Lam YM, Fan W, Bhosale SV, Bhosale SV, Zhang Q. Molecular Aggregation of Naphthalene Diimide(NDI) Derivatives in Electron Transport Layers of Inverted Perovskite Solar Cells and Their Influence on the Device Performance. Chem Asian J 2019; 15:112-121. [DOI: 10.1002/asia.201901452] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/15/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Wenbo Liu
- School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
- School of Electrical and Electronic EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Dada B. Shaikh
- Polymers and Functional Material DivisionCSIR-Indian Institute of Chemical Technology Hyderabad 500 007 Telangana India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad Uttar Pradesh 201 002 India
| | - Pedada Srinivasa Rao
- Polymers and Functional Material DivisionCSIR-Indian Institute of Chemical Technology Hyderabad 500 007 Telangana India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad Uttar Pradesh 201 002 India
| | - Rajesh S. Bhosale
- Department of ChemistryIndrashil University, Kadi Mehsana 382470 Gujarat India
| | - Ahmed Ali Said
- School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Adrian M. Mak
- Institute of High Performance Computing 1 Fusionopolis Way #16-16 Connexis Singapore 138632 Singapore
| | - Zongrui Wang
- School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Mu Zhao
- School of Physical and Mathematical SciencesNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Weibo Gao
- School of Physical and Mathematical SciencesNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Bingbing Chen
- School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Yeng Ming Lam
- School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Weijun Fan
- School of Electrical and Electronic EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
| | - Sidhanath V. Bhosale
- Polymers and Functional Material DivisionCSIR-Indian Institute of Chemical Technology Hyderabad 500 007 Telangana India
- Academy of Scientific and Innovative Research (AcSIR) Ghaziabad Uttar Pradesh 201 002 India
| | | | - Qichun Zhang
- School of Materials Science and EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
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23
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Zhao D, Hu H, Haselsberger R, Marcus RA, Michel-Beyerle ME, Lam YM, Zhu JX, La-O-Vorakiat C, Beard MC, Chia EEM. Monitoring Electron-Phonon Interactions in Lead Halide Perovskites Using Time-Resolved THz Spectroscopy. ACS Nano 2019; 13:8826-8835. [PMID: 31348643 DOI: 10.1021/acsnano.9b02049] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lead halide perovskite semiconductors have low-frequency phonon modes within the lead halide sublattice and thus are considered to be soft. The soft lattice is considered to be important in defining their interesting optoelectronic properties. Electron-phonon coupling governs hot-carrier relaxation, carrier mobilities, carrier lifetimes, among other important electronic characteristics. Directly observing the interplay between free charge carriers and phonons can provide details on how phonons impact these properties (e.g., exciton populations and other collective modes). Here, we observe a delicate interplay among carriers, phonons, and excitons in mixed-cation and mixed-halide perovskite films by simultaneously resolving the contribution of charge carriers and phonons in time-resolved terahertz photoconductivity spectra. We are able to observe directly the increase in phonon population during carrier cooling and discuss how thermal equilibrium populations of carriers and phonons modulate the carrier transport properties, as well as reduce the population of carriers within band tails. We are also able to observe directly the formation of free charge carriers when excitons interact with phonons and dissociate and to describe how free carriers and exciton populations exchange through phonon interactions. Finally, we also time-resolve how the carriers are screened via the Coulomb interaction at low and room temperatures. Our studies shed light on how charge carriers interact with the low-energy phonons and discuss implications.
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Affiliation(s)
- Daming Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 637371 Singapore
| | - Hongwei Hu
- School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore
| | - Reinhard Haselsberger
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 637371 Singapore
| | - Rudolph A Marcus
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 637371 Singapore
- Noyes Laboratory , California Institute of Technology , Pasadena , California 91125 , United States
| | - Maria-Elisabeth Michel-Beyerle
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 637371 Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering , Nanyang Technological University , 639798 Singapore
| | - Jian-Xin Zhu
- Theoretical Division and Center for Integrated Nanotechnologies , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States
| | - Chan La-O-Vorakiat
- Nanoscience and Nanotechnology Graduate Program, Faculty of Science , King Mongkut's University of Technology Thonburi (KMUTT) , Bangkok 10140 , Thailand
- Theoretical and Computational Science Center (TaCS) , KMUTT , Bangkok 10140 , Thailand
| | - Matthew C Beard
- Chemistry and Nanoscience Science Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 637371 Singapore
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24
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Wang K, Bohra H, Gonçalves RA, Bhatnagar H, Wu Y, Wang X, Wang Z, Wei X, Lam YM, Wang M. Multiscale Self-Assembly of a Phenyl-Flanked Diketopyrrolopyrrole Derivative: A Solution-Processable Building Block for π-Conjugated Supramolecular Polymers. Langmuir 2019; 35:5626-5634. [PMID: 30929445 DOI: 10.1021/acs.langmuir.9b00334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report a solution-processable π-conjugated molecular building block (denoted as PhDPP) consisting of a rigid and planar core of phenyl-flanked diketopyrrolopyrrole and "soft" branched alkoxy chains that endow the solubility in a variety of organic solvents. Intermolecular hydrogen bonding in PhDPP was revealed in nonpolar solvents above a threshold of concentration and below a critical point of temperature. The strong intermolecular interaction mainly contributed by the hydrogen-bonding and π-π interaction between PhDPP molecules promoted the formation of supramolecular polymeric structures in both solution and solid states and at interfaces. The supramolecular polymeric properties enabled solution-based processing of PhDPP under a variety of conditions into different structures including fibers and uniform thin films. The structure-property relationship that we established in the present system of PhDPP from the molecular to supramolecular level will be important to solution-process this type of H-bonding π-conjugated molecules for a variety of applications such as optoelectronic devices.
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Affiliation(s)
- Kai Wang
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Hassan Bohra
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Rui A Gonçalves
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , 639798 Singapore
| | - Harshangda Bhatnagar
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Yingjie Wu
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Xiaochen Wang
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Zheng Wang
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Xin Wei
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering , Nanyang Technological University , 50 Nanyang Avenue , 639798 Singapore
| | - Mingfeng Wang
- School of Chemical and Biomedical Engineering , Nanyang Technological University , 62 Nanyang Drive , 637459 Singapore
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25
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Wang X, Cheng L, Zhu D, Wu Y, Chen M, Wang Y, Zhao D, Boothroyd CB, Lam YM, Zhu JX, Battiato M, Song JCW, Yang H, Chia EEM. Ultrafast Spin-to-Charge Conversion at the Surface of Topological Insulator Thin Films. Adv Mater 2018; 30:e1802356. [PMID: 30370615 DOI: 10.1002/adma.201802356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 09/20/2018] [Indexed: 06/08/2023]
Abstract
Strong spin-orbit coupling, resulting in the formation of spin-momentum-locked surface states, endows topological insulators with superior spin-to-charge conversion characteristics, though the dynamics that govern it have remained elusive. Here, an all-optical method is presented, which enables unprecedented tracking of the ultrafast dynamics of spin-to-charge conversion in a prototypical topological insulator Bi2 Se3 /ferromagnetic Co heterostructure, down to the sub-picosecond timescale. Compared to pure Bi2 Se3 or Co, a giant terahertz emission is observed in the heterostructure that originates from spin-to-charge conversion, in which the topological surface states play a crucial role. A 0.12 ps timescale is identified that sets a technological speed limit of spin-to-charge conversion processes in topological insulators. In addition, it is shown that the spin-to-charge conversion efficiency is temperature independent in Bi2 Se3 as expected from the nature of the surface states, paving the way for designing next-generation high-speed optospintronic devices based on topological insulators at room temperature.
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Affiliation(s)
- Xinbo Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Liang Cheng
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Dapeng Zhu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yang Wu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Mengji Chen
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yi Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Daming Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Chris B Boothroyd
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Jian-Xin Zhu
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, NM, 87545, USA
| | - Marco Battiato
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Institute of Solid State Physics, Vienna University of Technology, 1040, Vienna, Austria
| | - Justin C W Song
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Institute of High Performance Computing, Agency for Science, Technology, and Research, Singapore, 138632, Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
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26
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Hu H, Meier F, Zhao D, Abe Y, Gao Y, Chen B, Salim T, Chia EEM, Qiao X, Deibel C, Lam YM. Efficient Room-Temperature Phosphorescence from Organic-Inorganic Hybrid Perovskites by Molecular Engineering. Adv Mater 2018; 30:e1707621. [PMID: 30062856 DOI: 10.1002/adma.201707621] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 06/02/2018] [Indexed: 05/17/2023]
Abstract
Solution-processed organic-inorganic hybrid perovskites are promising emitters for next-generation optoelectronic devices. Multiple-colored, bright light emission is achieved by tuning their composition and structures. However, there is very little research on exploring optically active organic cations for hybrid perovskites. Here, unique room-temperature phosphorescence from hybrid perovskites is reported by employing novel organic cations. Efficient room-temperature phosphorescence is activated by designing a mixed-cation perovskite system to suppress nonradiative recombination. Multiple-colored phosphorescence is achieved by molecular design. Moreover, the emission lifetime can be tuned by varying the perovskite composition to achieve persistent luminescence. Efficient room-temperature phosphorescence is demonstrated in hybrid perovskites that originates from the triplet states of the organic cations, opening a new dimension to the further development of perovskite emitters with novel functional organic cations for versatile display applications.
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Affiliation(s)
- Hongwei Hu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Fabian Meier
- Institut für Physik, Technische Universität Chemnitz, Chemnitz, D-09126, Germany
| | - Daming Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yuichiro Abe
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Yang Gao
- College of Physics Science & Energy, Shenzhen University, Shenzhen, 518060, China
| | - Bingbing Chen
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Xianfeng Qiao
- State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Carsten Deibel
- Institut für Physik, Technische Universität Chemnitz, Chemnitz, D-09126, Germany
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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27
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Ahmadi M, Pramana SS, Boothroyd C, Lam YM. Elucidating the relationship between crystallo-chemistry and optical properties of CIGS nanocrystals. Nanotechnology 2017; 28:045708. [PMID: 27997362 DOI: 10.1088/1361-6528/28/4/045708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The performance of solar cells fabricated using Cu(In,Ga)(S,Se)2 nanocrystal (NC) inks synthesized using the hot injection method has yielded efficiencies up to 12% recently. The efficiency of these devices is highly dependent on the chemical composition and crystallographic quality of the NCs. The former has been extensively discussed as it can be easily correlated to the optical properties of the film, but detailed crystallographic structure of these NCs has scarcely been discussed and it can influence both the optical and electrical properties. Hence both chemical composition and crystal structure should be explored for these NCs in order for this material to be further developed for application in thin film solar cells. In this work, a thorough investigation of the composition and crystal structure of CuIn x Ga1-x Se2 NCs synthesized using the hot injection method over the entire composition range (0 ≤ x ≤ 1) has been conducted. Raman spectroscopy of the NCs complements the information derived from x-ray diffraction (XRD) and electron probe microanalysis (EPMA). EPMA, which was carried out for the first time, indicates good controllability of the NC Ga/(In + Ga) ratio using this synthesis method. Raman spectroscopy reveals that CuInSe2 NCs are a mixture of chalcopyrite and sphalerite with disordered cations, whereas CuGaSe2 NCs are purely chalcopyrite. The lattice parameters determined from XRD were found to deviate from those calculated using Vegard's law for all compositions. Hence, it can be deduced that the lattice is distorted in the crystal. The optical and electrochemical band gap of CuIn x Ga1-x Se2 NCs increases as the Ga content increases. The energy band gap deviates from the theoretical values, which could be related to the contribution from cation disordering and strain. These results help to tailor the opto-electrical properties of semiconductors, which inherently depend on the crystalline quality, strain and composition.
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Affiliation(s)
- Mahshid Ahmadi
- Nanyang Technological University, School of Materials Science and Engineering, 50 Nanyang Avenue, 639798, Singapore
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28
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Solanki A, Bagui A, Long G, Wu B, Salim T, Chen Y, Lam YM, Sum TC. Effectiveness of External Electric Field Treatment of Conjugated Polymers in Bulk-Heterojunction Solar Cells. ACS Appl Mater Interfaces 2016; 8:32282-32291. [PMID: 27618844 DOI: 10.1021/acsami.6b08012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
External electric field treatment (EFT) on P3HT:PCBM bulk heterojunction (BHJ) devices was recently found to be a viable approach for improving the power conversion efficiencies (PCEs) through modulating the blend nanomorphology. However, its effectiveness over the broad family of polymer-fullerene blends remains unclear. Herein, we investigate the effects of external EFT on various polymer-fullerene blends with distinct morphologies stemming from the difference in molecular structure of the polymers (i.e., semicrystalline vs amorphous) in a bid to establish a clear morphology-function-charge dynamics relationship to the photovoltaic performance. Our findings reveal that EFT promotes self-organization of the semicrystalline thiophene-based conjugated polymers (i.e., P3HT and P3BT) while it was ineffective for the amorphous polymers (i.e., PTB7 and PCPDTBT) even at the maximum applied E-field of 8 kV cm-1. Transient absorption spectroscopy shows an improvement in the initial charge-carrier and polaron formation from delocalized excitons in the E-field treated semicrystalline blends compared to their untreated reference samples. Interfacial trap-assisted monomolecular and trap-free bimolecular recombination at nanosecond-microsecond time scale in the E-field treated P3BT:PC60BM devices are significantly suppressed. Importantly, our findings shed new light and provide guidelines on the effectiveness of utilizing external EFT to enhance the PCEs of a larger family of conjugated polymer-based BHJ OSCs.
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Affiliation(s)
- Ankur Solanki
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371
| | - Anirban Bagui
- Department of Physics, Indian Institute of Technology Kanpur , Kanpur 208016, India
| | - Guankui Long
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300071, China
- School of Materials Science and Engineering, Nankai University , Tianjin 300071, China
| | - Bo Wu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798
| | - Yongsheng Chen
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300071, China
- School of Materials Science and Engineering, Nankai University , Tianjin 300071, China
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798
- Energy Research Institute @ NTU (ERI@N) , 1 CleanTech Loop, #06-04 CleanTech One, Singapore 637141
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371
- Energy Research Institute @ NTU (ERI@N) , 1 CleanTech Loop, #06-04 CleanTech One, Singapore 637141
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29
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Hu H, Salim T, Chen B, Lam YM. Molecularly Engineered Organic-Inorganic Hybrid Perovskite with Multiple Quantum Well Structure for Multicolored Light-Emitting Diodes. Sci Rep 2016; 6:33546. [PMID: 27633084 PMCID: PMC5025709 DOI: 10.1038/srep33546] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/30/2016] [Indexed: 12/21/2022] Open
Abstract
Organic-inorganic hybrid perovskites have the potential to be used as a new class of emitters with tunable emission, high color purity and good ease of fabrication. Recent studies have so far been focused on three-dimensional (3D) perovskites, such as CH3NH3PbBr3 and CH3NH3PbI3 for green and infrared emission. Here, we explore a new series of hybrid perovskite emitters with a general formula of (C4H9NH3)2(CH3NH3)n-1PbnI3n+1 (where n = 1, 2, 3), which possesses a multiple quantum well structure. The quantum well thickness of these materials is adjustable through simple molecular engineering which results in a continuously tunable bandgap and emission spectra. Deep saturated red emission was obtained with a peak external quantum efficiency of 2.29% and a maximum luminance of 214 cd/m(2). Green and blue LEDs were also demonstrated through halogen substitutions in these hybrid perovskites. We expect these results to open up the way towards high performance perovskite LEDs through molecular-structure engineering of these perovskite emitters.
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Affiliation(s)
- Hongwei Hu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Bingbing Chen
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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30
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Xi L, Cho DY, Besmehn A, Duchamp M, Grützmacher D, Lam YM, Kardynał BE. Effect of Zinc Incorporation on the Performance of Red Light Emitting InP Core Nanocrystals. Inorg Chem 2016; 55:8381-6. [PMID: 27551948 DOI: 10.1021/acs.inorgchem.6b00747] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This report presents a systematic study on the effect of zinc (Zn) carboxylate precursor on the structural and optical properties of red light emitting InP nanocrystals (NCs). NC cores were assessed using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), energy-dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HRTEM). When moderate Zn:In ratios in the reaction pot were used, the incorporation of Zn in InP was insufficient to change the crystal structure or band gap of the NCs, but photoluminescence quantum yield (PLQY) increased dramatically compared with pure InP NCs. Zn was found to incorporate mostly in the phosphate layer on the NCs. PL, PLQY, and time-resolved PL (TRPL) show that Zn carboxylates added to the precursors during NC cores facilitate the synthesis of high-quality InP NCs by suppressing nonradiative and sub-band-gap recombination, and the effect is visible also after a ZnS shell is grown on the cores.
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Affiliation(s)
- Lifei Xi
- Semiconductor Nanoelectronics (PGI-9), Forschungszentrum Jülich, JARA-FIT , 52425 Jülich, Germany
| | - Deok-Yong Cho
- IPIT & Department of Physics, Chonbuk National University , Jeonju 54896, Republic of Korea
| | - Astrid Besmehn
- Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich , 52425 Jülich, Germany
| | - Martial Duchamp
- Ernst Ruska Centre, PGI-5, Forschungszentrum Jülich, JARA-FIT , 52425 Jülich, Germany
| | - Detlev Grützmacher
- Semiconductor Nanoelectronics (PGI-9), Forschungszentrum Jülich, JARA-FIT , 52425 Jülich, Germany
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University , Singapore 639798, Singapore
| | - Beata E Kardynał
- Semiconductor Nanoelectronics (PGI-9), Forschungszentrum Jülich, JARA-FIT , 52425 Jülich, Germany
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Abstract
Pulmonary arterial hypertension (PAH) in patients with systemic lupus erythematosus (SLE) is uncommon but is associated with poor survival. This study aimed to examine the long-term effects of bosentan, a dual endothelin-1 receptor antagonist, on symptomatology, haemodynamics and quality of life measures in SLE patients with symptomatic PAH. Four local patients had been followed up prospectively with pre-defined protocol during 12-months of bosentan treatment. Six minute walk distance (6MWD), NYHA functional class, Borg Dyspnoea Index (BDI) and SF-36 were measured at 0, 3, 6, 9 and 12 months. Systolic pulmonary arterial pressure (PAP) was measured by transthoracic echocardiography at zero, six and 12 months. Clinical parameters were analysed, pooling data from other SLE patients reported in the literature ( n = 4). Bosentan was found to result in significant improvement in 6MWD compared to baseline [+24.8 m, +26.2 m, +54 m and +62.7 m at three ( P = 0.001), six ( P = 0.001), nine ( P = 0.24) and 12 ( P = 0.01) months respectively]. A differential effect was found with greater response in patients with lower exercise capacity. This was accompanied by decrease in NYHA functional class, BDI, transient or sustained drop in systolic PAP and mild improvement in SF-36 domains including mental health, vitality, social function and general health. Significantly deranged liver function was found in one patient. Lupus (2007) 16, 279—285.
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Affiliation(s)
- M Y Mok
- Department of Medicine, Queen Mary Hospital, Pokfulam Road, Hong Kong.
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Mirbagheri N, Engberg S, Crovetto A, Simonsen SB, Hansen O, Lam YM, Schou J. Synthesis of ligand-free CZTS nanoparticles via a facile hot injection route. Nanotechnology 2016; 27:185603. [PMID: 27005863 DOI: 10.1088/0957-4484/27/18/185603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Single-phase, ligand-free Cu2ZnSnS4 (CZTS) nanoparticles that can be dispersed in polar solvents are desirable for thin film solar cell fabrication, since water can be used as the solvent for the nanoparticle ink. In this work, ligand-free nanoparticles were synthesized using a simple hot injection method and the precursor concentration in the reaction medium was tuned to control the final product. The as-synthesized nanoparticles were characterized using various techniques, and were found to have a near-stoichiometric composition and a phase-pure kesterite crystal structure. No secondary phases were detected with Raman spectroscopy or scanning transmission electron microscopy energy dispersive x-ray spectroscopy. Furthermore, high resolution transmission electron microscopy showed large-sized nanoparticles with an average diameter of 23 nm ± 11 nm. This approach avoids all organic materials and toxic solvents that otherwise could hinder grain growth and limit the deposition techniques. In addition the synthesis route presented here results in nanoparticles of a large size compared to other ligand-free CZTS nanoparticles, due to the high boiling point of the solvents selected. Large particle size in CZTS nanoparticle solar cells may lead to a promising device performance. The results obtained demonstrate the suitability of the synthesized nanoparticles for application in low cost thin film solar cells.
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Affiliation(s)
- N Mirbagheri
- DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark
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La-o-Vorakiat C, Xia H, Kadro J, Salim T, Zhao D, Ahmed T, Lam YM, Zhu JX, Marcus RA, Michel-Beyerle ME, Chia EEM. Phonon Mode Transformation Across the Orthohombic-Tetragonal Phase Transition in a Lead Iodide Perovskite CH3NH3PbI3: A Terahertz Time-Domain Spectroscopy Approach. J Phys Chem Lett 2016; 7:1-6. [PMID: 26633131 DOI: 10.1021/acs.jpclett.5b02223] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We study the temperature-dependent phonon modes of the organometallic lead iodide perovskite CH3NH3PbI3 thin film across the terahertz (0.5-3 THz) and temperature (20-300 K) ranges. These modes are related to the vibration of the Pb-I bonds. We found that two phonon modes in the tetragonal phase at room temperature split into four modes in the low-temperature orthorhombic phase. By use of the Lorentz model fitting, we analyze the critical behavior of this phase transition. The carrier mobility values calculated from the low-temperature phonon mode frequencies, via two theoretical approaches, are found to agree reasonably with the experimental value (∼2000 cm(2) V(-1) s(-1)) from a previous time-resolved THz spectroscopy work. Thus, we have established a possible link between terahertz phonon modes and the transport properties of perovskite-based solar cells.
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Affiliation(s)
- Chan La-o-Vorakiat
- Nanoscience and Nanotechnology Graduate Program, King Mongkut's University of Technology Thonburi , Bangkok 10140 Thailand
- Theoretical and Computational Science Center (TaCS), Faculty of Science, King Mongkut's University of Technology Thonburi , Bangkok 10140 Thailand
- Faculty of Science, King Mongkut's University of Technology Thonburi , Bangkok 10140 Thailand
| | - Huanxin Xia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore
| | - Jeannette Kadro
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore
- Laboratoire des Sciences Photomoléculaires, Ecole Polytechnique Fédérale de Lausanne , Switzerland
| | - Teddy Salim
- School of Materials Science and Engineering, Nanyang Technological University , 639798 Singapore
| | - Daming Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore
| | - Towfiq Ahmed
- Theoretical Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University , 639798 Singapore
| | - Jian-Xin Zhu
- Theoretical Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratories , Los Alamos, New Mexico 87545, United States
| | - Rudolph A Marcus
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore
- Noyes Laboratory, California Institute of Technology , Pasadena, California 91125, United States
| | - Maria-Elisabeth Michel-Beyerle
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore
| | - Elbert E M Chia
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 637371 Singapore
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Abstract
We present an alternative synthesis route to achieve larger Cu2ZnSnSe4 nanoparticles with targeted S/Se-ratios, by introducing selenium in the liquid phase – as liquid selenization!
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Affiliation(s)
- Sara Engberg
- DTU Fotonik
- Technical University of Denmark
- DK-4000 Roskilde
- Denmark
| | - Zhenggang Li
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Jun Yan Lek
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Jørgen Schou
- DTU Fotonik
- Technical University of Denmark
- DK-4000 Roskilde
- Denmark
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35
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Solanki A, Wu B, Salim T, Lam YM, Sum TC. Correlation between blend morphology and recombination dynamics in additive-added P3HT:PCBM solar cells. Phys Chem Chem Phys 2015; 17:26111-20. [DOI: 10.1039/c5cp03762j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The addition of a small amount of high boiling point solvent in organic donor/acceptor blends to control their morphology is one viable approach to enhance the power conversion efficiency of thermal-annealing free bulk heterojunction (BHJ) organic solar cells.
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Affiliation(s)
- Ankur Solanki
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - Bo Wu
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
- Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE)
| | - Teddy Salim
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
- Energy Research Institute @ NTU (ERI@N)
- Singapore
| | - Yeng Ming Lam
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
- Energy Research Institute @ NTU (ERI@N)
- Singapore
| | - Tze Chien Sum
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
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36
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Xi L, Cho DY, Duchamp M, Boothroyd CB, Lek JY, Besmehn A, Waser R, Lam YM, Kardynal B. Understanding the role of single molecular ZnS precursors in the synthesis of In(Zn)P/ZnS nanocrystals. ACS Appl Mater Interfaces 2014; 6:18233-42. [PMID: 25252171 DOI: 10.1021/am504988j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Environmentally friendly nanocrystals (NCs) such as InP are in demand for various applications, such as biomedical labeling, solar cells, sensors, and light-emitting diodes (LEDs). To fulfill their potential applications, the synthesis of such high-quality "green" InP NCs required further improvement so as to achieve better stability, higher brightness NCs, and also to have a more robust synthesis route. The present study addresses our efforts on the synthesis of high-quality In(Zn)P/ZnS core-shell NCs using an air- and moisture-stable ZnS single molecular precursor (SMP) and In(Zn)P cores. The SMP method has recently emerged as a promising route for the surface overcoating of NCs due to its simplicity, high reproducibility, low reaction temperature, and flexibility in controlling the reaction. The synthesis involved heating the In(Zn)P core solution and Zn(S2CNR2) (where R = methyl, ethyl, butyl, or benzyl and referred to as ZDMT, ZDET, ZDBT, or ZDBzT, respectively) in oleylamine (OLA) to 90-250 °C for 0.5-2.5 h. In this work, we systematically studied the influence of different SMP end groups, the complex formation and stability between the SMP and oleylamine (OLA), the reaction temperature, and the amount of SMP on the synthesis of high-quality In(Zn)P/ZnS NCs. We found that thiocarbamate end groups are an important factor contributing to the low-temperature growth of high-quality In(Zn)P/ZnS NCs, as the end groups affect the polarity of the molecules and result in a different steric arrangement. We found that use of SMP with bulky end groups (ZDBzT) results in nanocrystals with higher photoluminescence quantum yield (PL QY) and better dispersibility than those synthesized with SMPs with the shorter alkyl chain groups (ZDMT, ZDET, or ZDBT). At the optimal conditions, the PL QY of red emission In(Zn)P/ZnS NCs is 55 ± 4%, which is one of the highest values reported. On the basis of structural (XAS, XPS, XRD, TEM) and optical characterization, we propose a mechanism for the growth of a ZnS shell on an In(Zn)P core.
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Affiliation(s)
- Lifei Xi
- Semiconductor Nanoelectronics (PGI-9), §Ernst Ruska-Centre and Peter Grünberg Institut, and ⊥Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich , 52425 Jülich, Germany
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37
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Affiliation(s)
- Zhenggang Li
- School
of Materials Science and Engineering, Nanyang Technological University, Blk N4.1, Nanyang Avenue, Singapore 639798
- Energy Research Institute@NTU
(ERI@N), Research Technoplaza Level
5, Nanyang Drive, Singapore 637553
| | - Alvic Lim Kar Lui
- School
of Materials Science and Engineering, Nanyang Technological University, Blk N4.1, Nanyang Avenue, Singapore 639798
| | - Kwan Hang Lam
- School
of Materials Science and Engineering, Nanyang Technological University, Blk N4.1, Nanyang Avenue, Singapore 639798
| | - Lifei Xi
- Semiconductor Nanoelectronics (PGI-9), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany
| | - Yeng Ming Lam
- School
of Materials Science and Engineering, Nanyang Technological University, Blk N4.1, Nanyang Avenue, Singapore 639798
- Energy Research Institute@NTU
(ERI@N), Research Technoplaza Level
5, Nanyang Drive, Singapore 637553
- Institute of Materials for Electronic Engineering
II, RWTH-Aachen, Sommerfeldstr. 24, D-52074 Aachen, Germany
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Chen W, Zhang Q, Salim T, Ekahana SA, Wan X, Sum TC, Lam YM, Hon Huan Cheng A, Chen Y, Zhang Q. Synthesis and photovoltaic properties of novel C60 bisadducts based on benzo[2,1,3]-thiadiazole. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.01.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Yang D, Lu Z, Rui X, Huang X, Li H, Zhu J, Zhang W, Lam YM, Hng HH, Zhang H, Yan Q. Synthesis of Two-Dimensional Transition-Metal Phosphates with Highly Ordered Mesoporous Structures for Lithium-Ion Battery Applications. Angew Chem Int Ed Engl 2014; 53:9352-5. [DOI: 10.1002/anie.201404615] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Indexed: 11/05/2022]
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40
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Yang D, Lu Z, Rui X, Huang X, Li H, Zhu J, Zhang W, Lam YM, Hng HH, Zhang H, Yan Q. Synthesis of Two-Dimensional Transition-Metal Phosphates with Highly Ordered Mesoporous Structures for Lithium-Ion Battery Applications. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404615] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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41
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Trang Pham TT, Koh TM, Nonomura K, Lam YM, Mathews N, Mhaisalkar S. Reducing Mass-Transport Limitations in Cobalt-Electrolyte-Based Dye-Sensitized Solar Cells by Photoanode Modification. Chemphyschem 2014; 15:1216-21. [DOI: 10.1002/cphc.201301056] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 02/17/2014] [Indexed: 11/12/2022]
Affiliation(s)
- Thi Thu Trang Pham
- Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, 1 CleanTech Loop, 06-04 CleanTech One, Singapore 637141 (Singapore); Division of Materials Technology, School of Materials Science and Engineering, Nanyang Technological University, Block N4.1 Nanyang Avenue, Singapore 639798 (Singapore)
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42
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Lek JY, Xing G, Sum TC, Lam YM. Electron transport limitation in P3HT:CdSe nanorods hybrid solar cells. ACS Appl Mater Interfaces 2014; 6:894-902. [PMID: 24351093 DOI: 10.1021/am4041515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hybrid solar cells have the potential to be efficient solar-energy-harvesting devices that can combine the benefits of solution-processable organic materials and the extended absorption offered by inorganic materials. In this work, an understanding of the factors limiting the performance of hybrid solar cells is explored. Through photovoltaic-device characterization correlated with transient absorption spectroscopy measurements, it was found that the interfacial charge transfer between the organic (P3HT) and inorganic (CdSe nanorods) components is not the factor limiting the performance of these solar cells. The insulating original ligands retard the charge recombination between the charge-transfer states across the CdSe-P3HT interface, and this is actually beneficial for charge collection. These cells are, in fact, limited by the subsequent electron collection via CdSe nanoparticles to the electrodes. Hence, the design of a more continuous electron-transport pathway should greatly improve the performance of hybrid solar cells in the future.
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Affiliation(s)
- Jun Yan Lek
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798
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43
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Salim T, Lek JY, Bräuer B, Fichou D, Lam YM. Correction: Polymer nanofibers: preserving nanomorphology in ternary blend organic photovoltaics. Phys Chem Chem Phys 2014. [DOI: 10.1039/c4cp90162b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Abstract
Two new quinoxaline-functionalized C60 derivatives with high LUMO levels have been synthesized and applied in organic solar cells. BHJ-OSCs incorporating P3HT as donor and TQMA (or TQBA) as acceptor exhibit an open-circuit voltage (VOC) of 0.76 V (or 0.84 V), which is about 0.12 V (or 0.20 V) higher than PCBM as electron acceptor.
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Affiliation(s)
- Wangqiao Chen
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore 639798, Singapore
- Institute for Sports Research
- Nanyang Technological University
| | - Teddy Salim
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore 639798, Singapore
| | - Haijun Fan
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore 639798, Singapore
| | - Lewis James
- School of Sport
- Exercise and Health Sciences
- Loughborough University
- Leicestershire, UK
| | - Yeng Ming Lam
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore 639798, Singapore
| | - Qichun Zhang
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore 639798, Singapore
- Institute for Sports Research
- Nanyang Technological University
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45
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Rajwar D, Liu X, Lim ZB, Cho SJ, Chen S, Thomas JMH, Trewin A, Lam YM, Sum TC, Grimsdale AC. Novel self-assembled 2D networks based on zinc metal ion co-ordination: synthesis and comparative study with 3D networks. RSC Adv 2014. [DOI: 10.1039/c3ra47377e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Novel 2-D supramolecular networks were made by metal-ion coordination, and their properties compared with similar 3-D networks.
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Affiliation(s)
- Deepa Rajwar
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Xinfeng Liu
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - Zheng Bang Lim
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Sung Ju Cho
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Shi Chen
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - Jens M. H. Thomas
- Institute of Integrative Biology
- University of Liverpool
- Liverpool, UK
| | - Abbie Trewin
- Department of Chemistry
- Lancaster University
- Lancaster, UK
| | - Yeng Ming Lam
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
| | - Tze Chien Sum
- Division of Physics and Applied Physics
- School of Physical and Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - Andrew C. Grimsdale
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore
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46
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Li Z, Ho JCW, Lee KK, Zeng X, Zhang T, Wong LH, Lam YM. Environmentally friendly solution route to kesterite Cu2ZnSn(S,Se)4thin films for solar cell applications. RSC Adv 2014. [DOI: 10.1039/c4ra03349c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Solar cells were made from Cu2ZnSn(S,Se)4thin films prepared using an ink consisting of CuS, ZnS and SnS2nanoparticles dispersed in water.
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Affiliation(s)
- Zhenggang Li
- School of Materials Science and Engineering
- Nanyang Technological University
- , Singapore 639798
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
| | - John C. W. Ho
- School of Materials Science and Engineering
- Nanyang Technological University
- , Singapore 639798
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
| | - Kian Keat Lee
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
- , Singapore 637553
| | - Xin Zeng
- School of Materials Science and Engineering
- Nanyang Technological University
- , Singapore 639798
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
| | - Tianliang Zhang
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
- , Singapore 637553
| | - Lydia Helena Wong
- School of Materials Science and Engineering
- Nanyang Technological University
- , Singapore 639798
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
| | - Yeng Ming Lam
- School of Materials Science and Engineering
- Nanyang Technological University
- , Singapore 639798
- Energy Research Institute @ NTU (ERI@N)
- Research Technoplaza Level 5
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47
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Salim T, Lek JY, Bräuer B, Fichou D, Lam YM. Polymer nanofibers: preserving nanomorphology in ternary blend organic photovoltaics. Phys Chem Chem Phys 2014; 16:23829-36. [DOI: 10.1039/c4cp03108c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The morphology of donor–acceptor blends holds the key to good performance through the balancing of good exciton dissociation efficiency and interconnectivity for good charge collection.
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Affiliation(s)
- Teddy Salim
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore, Singapore
| | - Jun Yan Lek
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore, Singapore
| | - Björn Bräuer
- Stanford Institute for Materials and Energy Science
- Stanford University
- , USA
| | - Denis Fichou
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 8232
- Institut Parisien de Chimie Moléculaire
- Paris, France
| | - Yeng Ming Lam
- School of Materials Science and Engineering
- Nanyang Technological University
- Singapore, Singapore
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48
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Lam KH, Foong TRB, Ooi ZE, Zhang J, Grimsdale AC, Lam YM. Enhancing the performance of solution-processed bulk-heterojunction solar cells using hydrogen-bonding-induced self-organization of small molecules. ACS Appl Mater Interfaces 2013; 5:13265-13274. [PMID: 24215496 DOI: 10.1021/am4042614] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Small-molecule solar-cell performance is highly sensitive to the crystallinity and intermolecular connectivity of the molecules. In order to enhance the crystallinity for the solution-processed small molecule, it is possible to make use of carboxylic acid end-functional groups to drive hydrogen-bonding-induced π-π stacking of conjugated molecules. Herein, we report the synthesis and characterization of quarterthiophenes with carboxylic acid as end groups. The formation of hydrogen bonds between neighboring acid groups gives rise to a pseudo-polymeric structure in the molecules, which leads to substantial improvement in the organization and crystallinity of the active layers. This resulted in a four-fold increase in the hole mobility and a two-fold improvement in the performance of the solar cell device for the acid-functionalized molecule, compared to its ester analogue. More importantly, optimal device performance for the acid-functionalized molecule was achieved for the as-cast film, thereby reducing the reliance on thermal annealing and solvent additives.
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Affiliation(s)
- Kwan Hang Lam
- School of Materials Science and Engineering, Nanyang Technological University , Blk N4.1, Nanyang Avenue, Singapore 639798
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49
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Ahmadi M, Pramana SS, Batabyal SK, Boothroyd C, Mhaisalkar SG, Lam YM. Synthesis of Cu2SnSe3 Nanocrystals for Solution Processable Photovoltaic Cells. Inorg Chem 2013; 52:1722-8. [DOI: 10.1021/ic301141w] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mahshid Ahmadi
- School of
Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Stevin S. Pramana
- Facility for Analysis, Characterization,
Testing and Simulation, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Sudip K. Batabyal
- Energy Research Institute @ NTU, Nanyang Technological University, 50 Nanyang Drive, 637553,
Singapore
| | - Chris Boothroyd
- Ernst Ruska-Centrum und Peter Grünberg Institut, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Subodh G. Mhaisalkar
- School of
Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
- Energy Research Institute @ NTU, Nanyang Technological University, 50 Nanyang Drive, 637553,
Singapore
| | - Yeng Ming Lam
- School of
Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
- Energy Research Institute @ NTU, Nanyang Technological University, 50 Nanyang Drive, 637553,
Singapore
- Institute of Materials for Electronic Engineering II, RWTH-Aachen, Sommerfeldstr.
24, D-52074 Aachen, Germany
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50
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Sonar P, Tan HS, Sun S, Lam YM, Dodabalapur A. Isoindigo dye incorporated copolymers with naphthalene and anthracene: promising materials for stable organic field effect transistors. Polym Chem 2013. [DOI: 10.1039/c2py20942j] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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