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Pate D, Spence GC, Graves LS, Arachchige IU, Özgür Ü. Size-Tunable Band Structure and Optical Properties of Colloidal Silicon Nanocrystals Synthesized via Thermal Disproportionation of Hydrogen Silsesquioxane Polymers. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:10483-10491. [PMID: 38957369 PMCID: PMC11215768 DOI: 10.1021/acs.jpcc.4c01462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/04/2024] [Accepted: 06/07/2024] [Indexed: 07/04/2024]
Abstract
Dodecane-capped silicon nanocrystals (NCs) were synthesized by using a low-temperature (800-1100 °C) polymer variant of traditional hydrogen silsesquioxane thermal disproportionation. Highly crystalline Si NCs having tunable diameters (3.0-6.7 nm) and thus photoluminescence (PL) peaks (1.68-1.29 eV) were attained via changes in the maximum annealing temperature. Modifications in the NC band structure with diameter were explored by comparison of emission with absorption spectra obtained from diffuse reflectance spectroscopy. Large apparent energy shifts between onsets and PL were noted, being significant for smaller NCs (≤∼4.0 nm). This, along with comparatively "softer" onsets, is commensurate with density of states elongation around PL peaks associated with increasing confinement predicted for indirect semiconductor nanostructures. Tauc analyses of absorption additionally revealed three distinguishable optical transitions in all NCs: attributed to indirect Γ25'-Δ1 in lower energy ranges (likely the emission progenitor), indirect Γ25'-L1 overtaken by quasi-direct Γ-X wave function mixing for NC diameters ≤∼4.0 nm within the midenergy regime, and direct Γ25'-Γ15 transitions at energies nearing and above ∼3 eV.
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Affiliation(s)
- David
S. Pate
- Department
of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284-9052, United States
| | - Griffin C. Spence
- Department
of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-9059, United
States
| | - Lisa S. Graves
- Department
of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-9059, United
States
| | - Indika U. Arachchige
- Department
of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284-9059, United
States
| | - Ümit Özgür
- Department
of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284-9052, United States
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2
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Othman DM, Weinstein J, Huang N, Ming W, Lyu Q, Hou B. Solution-processed colloidal quantum dots for internet of things. NANOSCALE 2024; 16:10947-10974. [PMID: 38804109 DOI: 10.1039/d4nr00203b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Colloidal quantum dots (CQDs) have been a hot research topic ever since they were successfully fabricated in 1993 via the hot injection method. The Nobel Prize in Chemistry 2023 was awarded to Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov for the discovery and synthesis of quantum dots. The Internet of Things (IoT) has also attracted a lot of attention due to the technological advancements and digitalisation of the world. This review first aims to give the basics behind QD physics. After that, the history behind CQD synthesis and the different methods used to synthesize most widely researched CQD materials (CdSe, PbS and InP) are revisited. A brief introduction to what IoT is and how it works is also mentioned. Then, the most widely researched CQD devices that can be used for the main IoT components are reviewed, where the history, physics, the figures of merit (FoMs) and the state-of-the-art are discussed. Finally, the challenges and different methods for integrating CQDs into IoT devices are discussed, mentioning the future possibilities that await CQDs.
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Affiliation(s)
- Diyar Mousa Othman
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, UK.
| | - Julia Weinstein
- Department of Chemistry, The University of Sheffield, Sheffield, S3 7HF, UK
| | | | - Wenlong Ming
- School of Engineering, Cardiff University, Cardiff, CF24 3AA, UK
| | - Quan Lyu
- Cambridge Research Centre, Huawei Technologies Research & Development (UK) Ltd, Cambridge, CB4 0FY, UK.
| | - Bo Hou
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, UK.
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3
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Chen L, Zhang S, Duan Y, Song X, Chang M, Feng W, Chen Y. Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application. Chem Soc Rev 2024; 53:1167-1315. [PMID: 38168612 DOI: 10.1039/d1cs01022k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.
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Affiliation(s)
- Liang Chen
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
| | - Shanshan Zhang
- Department of Ultrasound Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P. R. China
| | - Yanqiu Duan
- Laboratory Center, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200071, P. R. China.
| | - Xinran Song
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
| | - Meiqi Chang
- Laboratory Center, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200071, P. R. China.
| | - Wei Feng
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
| | - Yu Chen
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China.
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4
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Ueda H, Saitow KI. Cost-Effective Ultrabright Silicon Quantum Dots and Highly Efficient LEDs from Low-Carbon Hydrogen Silsesquioxane Polymers. ACS APPLIED MATERIALS & INTERFACES 2024; 16:985-997. [PMID: 38153210 DOI: 10.1021/acsami.3c11120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Cost-effective methods of synthesizing bright colloidal silicon quantum dots (SiQDs) for use as heavy-metal-free QDs, which have applications as light sources in biomedicine and displays, are required. We report simple protocols for synthesizing ultrabright colloidal SiQDs and fabricating SiQD LEDs based on hydrogen silsesquioxane (HSQ) polymer synthesis. Red photoluminescence with a quantum yield (PLQY) of 60-80% and LEDs with an external quantum efficiency (EQE) of >10% were obtained at 1/3600th of the cost of existing methods. This was achieved by using HSiCl3 and a low-polarity solvent to prepare the HSQ polymer and by optimizing the LED hole-injection layer thickness. A stochastic analysis of 31 SiQD syntheses revealed that SiQDs with the highest PLQYs were obtained from a hard, low-carbon HSQ polymer precursor containing many Si-H groups and cage structures. Notably, simple FTIR measurements predicted whether a HSQ polymer would yield high-PLQY SiQDs and high-EQE LEDs. These straightforward, cost-effective protocols should lead to advances in SiQD synthesis and LED fabrication methods.
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Affiliation(s)
- Honoka Ueda
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Ken-Ichi Saitow
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
- Department of Materials Science, Natural Science Center for Basic Research and Development (N-BARD), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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5
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Cheong IT, Yang Szepesvari L, Ni C, Butler C, O'Connor KM, Hooper R, Meldrum A, Veinot JGC. Not all silicon quantum dots are equal: photostability of silicon quantum dots with and without a thick amorphous shell. NANOSCALE 2024; 16:592-603. [PMID: 38058198 DOI: 10.1039/d3nr04478e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Luminescent colloidal silicon quantum dots (SiQDs) are sustainable alternatives to metal-based QDs for various optical applications. While the materials are reliant on their photoluminescence efficiency, the relationship between the structure and photostability of SiQDs is yet to be well studied. An amorphous silicon (a-Si) shell was recently discovered in SiQDs prepared by thermally-processed silicon oxides. As a-Si is known as a source of defects upon UV irradiation, the disordered shell could potentially have an adverse effect on the optical properties of nanoparticles. Herein, the photostability of ∼5 nm diameter SiQDs with an amorphous shell was compared with that of over-etched SiQDs of equivalent dimensions that bore an a-Si shell of negligible thickness. An UV-induced degradation study was conducted by subjecting toluene solutions of SiQDs to 365 nm light-emitting diodes (LEDs) under an inert atmosphere for predetermined times up to 72 hours. The structure, composition, and optical responses of the exposed SiQDs were evaluated.
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Affiliation(s)
- I Teng Cheong
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | | | - Chuyi Ni
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | - Cole Butler
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | - Kevin M O'Connor
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | - Riley Hooper
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
| | - Alkiviathes Meldrum
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
| | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
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6
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Zhang X, Li J, Wang T, Liu N, Su X. Cerenkov radiation-mediated in situ activation of silicon nanocrystals for NIR optical imaging. Chem Commun (Camb) 2023; 59:13990-13992. [PMID: 37937992 DOI: 10.1039/d3cc04468h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Cerenkov radiation from radiopharmaceuticals (18F-FDG) serves as an internal light source to excite UV-responsive silicon nanocrystals for near-infrared luminescence imaging that offers deeper tissue penetration and high signal-to-noise ratio.
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Affiliation(s)
- Xun Zhang
- PET Center, Department of Nuclear Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
- School of Medicine, Xiamen University, Xiamen 361005, China
| | - Jingchao Li
- PET Center, Department of Nuclear Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
| | - Tingting Wang
- PET Center, Department of Nuclear Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
- School of Medicine, Xiamen University, Xiamen 361005, China
| | - Nian Liu
- PET Center, Department of Nuclear Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
| | - Xinhui Su
- PET Center, Department of Nuclear Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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7
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O'Connor KM, Rubletz A, Trach J, Butler C, Veinot JGC. Understanding silicon monoxide gas evolution from mixed silicon and silica powders. NANOSCALE HORIZONS 2023. [PMID: 37115104 DOI: 10.1039/d3nh00076a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Silicon on silica materials are ubiquitous in 21st century technology. From nanoparticles to integrated circuits, these systems are integral for modern semiconductor fabrication. While the Si-SiO2 interface is often (incorrectly) presumed to be stable, the direct reduction of silica by silicon is possible at high temperatures, resulting in the evolution of silicon monoxide (SiO) gas. Under appropriate conditions, this somewhat unexpected reaction can complicate solid state nanomaterial syntheses by etching away the desired products. This report describes an investigation into the SiO evolution reaction by interrogation of powdered Si-SiO2 mixtures before and after thermal treatment. The impacts of processing temperature, time, and sample composition are examined and discussed. Of particular importance, this investigation reveals the underappreciated role of silica crystallinity (cristobalite) in this solid-state reaction under comparatively low temperature conditions (ca. 1200 °C). With an improved understanding of SiO evolution, we hope to inspire new creative pathways for Si-SiO2 interface manipulation.
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Affiliation(s)
- Kevin M O'Connor
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Abbie Rubletz
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Jonathan Trach
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Cole Butler
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
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8
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Yamada H, Watanabe J, Nemoto K, Sun HT, Shirahata N. Postproduction Approach to Enhance the External Quantum Efficiency for Red Light-Emitting Diodes Based on Silicon Nanocrystals. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12234314. [PMID: 36500937 PMCID: PMC9735803 DOI: 10.3390/nano12234314] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 05/08/2023]
Abstract
Despite bulk crystals of silicon (Si) being indirect bandgap semiconductors, their quantum dots (QDs) exhibit the superior photoluminescence (PL) properties including high quantum yield (PLQY > 50%) and spectral tunability in a broad wavelength range. Nevertheless, their low optical absorbance character inhibits the bright emission from the SiQDs for phosphor-type light emitting diodes (LEDs). In contrast, a strong electroluminescence is potentially given by serving SiQDs as an emissive layer of current-driven LEDs with (Si-QLEDs) because the charged carriers are supplied from electrodes unlike absorption of light. Herein, we report that the external quantum efficiency (EQE) of Si-QLED was enhanced up to 12.2% by postproduction effect which induced by continuously applied voltage at 5 V for 9 h. The active layer consisted of SiQDs with a diameter of 2.0 nm. Observation of the cross-section of the multilayer QLEDs device revealed that the interparticle distance between adjacent SiQDs in the emissive layer is reduced to 0.95 nm from 1.54 nm by “post-electric-annealing”. The shortened distance was effective in promoting charge injection into the emission layer, leading improvement of the EQE.
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Affiliation(s)
- Hiroyuki Yamada
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
| | - Junpei Watanabe
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
- Department of Physics, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
| | - Kazuhiro Nemoto
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
| | - Hong-Tao Sun
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Naoto Shirahata
- International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
- Department of Physics, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
- Correspondence: ; Tel.: +81-29-859-2743
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9
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Shakiba M, Stippell E, Li W, Akimov AV. Nonadiabatic Molecular Dynamics with Extended Density Functional Tight-Binding: Application to Nanocrystals and Periodic Solids. J Chem Theory Comput 2022; 18:5157-5180. [PMID: 35758936 DOI: 10.1021/acs.jctc.2c00297] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, we report a new methodology for nonadiabatic molecular dynamics calculations within the extended tight-binding (xTB) framework. We demonstrate the applicability of the developed approach to finite and periodic systems with thousands of atoms by modeling "hot" electron relaxation dynamics in silicon nanocrystals and electron-hole recombination in both a graphitic carbon nitride monolayer and a titanium-based metal-organic framework (MOF). This work reports the nonadiabatic dynamic simulations in the largest Si nanocrystals studied so far by the xTB framework, with diameters up to 3.5 nm. For silicon nanocrystals, we find a non-monotonic dependence of "hot" electron relaxation rates on the nanocrystal size, in agreement with available experimental reports. We rationalize this relationship by a combination of decreasing nonadiabatic couplings related to system size and the increase of available coherent transfer pathways in systems with higher densities of states. We emphasize the importance of proper treatment of coherences for obtaining such non-monotonic dependences. We characterize the electron-hole recombination dynamics in the graphitic carbon nitride monolayer and the Ti-containing MOF. We demonstrate the importance of spin-adaptation and proper sampling of surface hopping trajectories in modeling such processes. We also assess several trajectory surface hopping schemes and highlight their distinct qualitative behavior in modeling the excited-state dynamics in superexchange-like models depending on how they handle coherences between nearly parallel states.
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Affiliation(s)
- Mohammad Shakiba
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Elizabeth Stippell
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Wei Li
- School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, China
| | - Alexey V Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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M A, John BK, Chacko AR, Mohan C, Mathew B. A Review on Carbon Quantum Dot Based Semiconductor Photocatalysts for the Abatement of Refractory Pollutants. Chemphyschem 2022; 23:e202100873. [PMID: 35320623 DOI: 10.1002/cphc.202100873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/15/2022] [Indexed: 11/10/2022]
Abstract
Photocatalysis is a green approach frequently utilised to eliminate a variety of environmentally hazardous refractory pollutants. Accordingly, the modification of semiconductor photocatalysts with Carbon Quantum Dots (CQDs) is of great importance for the treatment of such pollutants due to their attractive physical and chemical properties. CQDs are a perfect candidate to handle photocatalysts of high-performance since they operate as co-catalysts and as visible light harvesters. The higher separation rate of electron-hole pairs in the photocatalytic system is attributable to better photodegradation efficiency. This review classifies CQD based photocatalysts as pure, doped and composite materials and discusses the specific advantages of CQDs in visible light-driven photocatalysis. In this work, the versatile roles of CQDs in CQD-based photocatalytic systems are thoroughly discussed and s u mmarised.
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Affiliation(s)
- Athulya M
- Mahatma Gandhi University, School of Chemical Sciences, INDIA
| | - Bony K John
- Mahatma Gandhi University, School of Chemical Sciences, INDIA
| | - Anu Rose Chacko
- Mahatma Gandhi University, School of Chemical Sciences, INDIA
| | - Chitra Mohan
- Mahatma Gandhi University, School of Chemical Sciences, INDIA
| | - Beena Mathew
- Mahatma Gandhi University, School Of Chemical Sciences, Priyadarshini Hills PO, Kottayam, 686560, Kottayam, INDIA
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