Query: Carbon quantum dots and their applications

Candidate papers:

abstract: Fluorescent carbon nanoparticles or carbon quantum dots (CQDs) are a new class of carbon nanomaterials that have emerged recently and have garnered much interest as potential competitors to conventional semiconductor quantum dots. In addition to their comparable optical properties, CQDs have the desired advantages of low toxicity, environmental friendliness low cost and simple synthetic routes. Moreover, surface passivation and functionalization of CQDs allow for the control of their physicochemical properties. Since their discovery, CQDs have found many applications in the fields of chemical sensing, biosensing, bioimaging, nanomedicine, photocatalysis and electrocatalysis. This article reviews the progress in the research and development of CQDs with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.
author_names: Shi Ying Lim

Wei Shen

Zhiqiang Gao
title: Carbon quantum dots and their applications.
venue: Chemical Society reviews
year: 2015

abstract: Carbon quantum dots (CQDs) are a member of carbon nanostructures family which have received increasing attention for their photoluminescence (PL) physical and chemical stability and low toxicity. The classical semiconductor quantum dots (QDs) are semiconductor particles that are able to emit fluorescence by excitation. The CQDs is mainly referred to photoluminescent carbon nanoparticles less than 10 nm, with surface modification or functionalization. Contrary to other carbon nanostructures, CQDs can be synthesized and functionalized fast and easily. The fluorescence origin of the CQDs is a controversial issue which depends on carbon source, experimental conditions, and functional groups. However, PL emissions originated from conjugated p domains and surface defects have been proposed for the PL emission mechanisms of the CQDs. These nanostructures have been used as nontoxic alternatives to the classical heavy metals containing semiconductor QDs in some applications such as in vivo and in vitro bio imaging, drug delivery, photosensors, chemiluminescence (CL) and etc. This paper will introduce CQDs, their structure, and PL characteristics. Recent advances of the application of CQDs in biotechnology, sensors, and CL is comprehensively discussed.
author_names: Mohammad Jafar Molaei
title: A review on nanostructured carbon quantum dots and their applications in biotechnology, sensors, and chemiluminescence.
venue: Talanta
year: 2019

abstract: Carbon quantum dots (CQDs) are a fascinating class of carbon nanoparticles with sizes around 10 nm. The unique properties of CQDs are low toxicity, chemical inertness, excellent biocompatibility, photo induced electron transfer and highly tunable photoluminescence behaviour. Sustainable raw materials are commonly used for the fabrication of CQDs because they are cost effective, eco friendly and effective to minimise waste production. CQDs can be fabricated using laser ablation, microwave irradiation, hydrothermal reaction, electrochemical oxidation, reflux method and ultrasonication. These methods undergo several chemical reactions such as oxidation, carbonisation, pyrolysis and polymerisation processes to produce CQDs. Due to small particle sizes of CQDs, they possess strong tunable fluorescent properties and highly photo luminescent emissions. It also contains oxygen based functional groups and highly desired properties as semiconductor nanoparticles. Therefore, CQDs are promising nanomaterials for photo catalysis, ions sensing, biological imaging, heavy metal detection, adsorption treatment, supercapacitor, membrane fabrication and water pollution treatment. This review paper will discuss the physical and chemical properties of CQDs, raw materials and methods used in the fabrication of CQDs, the stability of CQDs as well as their potential applications in wastewater treatment and biomedical field.
author_names: Umairah Abd Rani

Law Yong Ng

Ching Yin Ng

Ebrahim Mahmoudi
title: A review of carbon quantum dots and their applications in wastewater treatment.
venue: Advances in colloid and interface science
year: 2020

abstract: Abstract Background In recent years, carbon quantum dots (CQDs) has received a lot of attentions owing to their great physical and optical properties. There are different kinds of carbon sources applied in various fields, however, CQDs used in the food industry have higher requirements for their safety. Therefore, it is the best way to use natural materials for preparing CQDs without the participation of chemicals. Up to now, there are many natural food products for preparing CQDs. However, food waste is often overlooked. Actually, food waste is rich in carbon sources. And the efficient utilization of food waste plays a positive role in economic benefit and environmental pollution. Scope and approach Proper use of food waste as carbon source not only facilitates food safety detection but also increases byproduct value. This paper was intended to review the research progress of food waste utilization as carbon precursor and applications in food safety detection. The approaches of preparing CQDs from different sorts of food wastes, the characteristics and applications of CQDs were described in detail. Particularly the applications in food quality and safety detection including food additives, heavy metal ions were also elaborated. Key findings and conclusions Currently, food waste as carbon source could be divided into plant byproducts, animal food byproducts and food processing byproducts. Moreover, there are many applications of food waste as carbon precursor in CQDs technology to detect food additives and heavy metal ions. However, detection of pathogens and other harmful substances in food industry is rare. Last but not least, it was concluded that food waste had potential to prepare CQDs and be applied to food safety detection.
author_names: Hanzhi Fan

Min Zhang

Bhesh R Bhandari

Chaohui Yang
title: Food waste as a carbon source in carbon quantum dots technology and their applications in food safety detection
year: 2020

abstract: In recent years, nano carbon quantum dots (CQDs) have received increasing attention due to their properties such as small size, fluorescence emission, chemical stability, water solubility, easy synthesis, and the possibility of functionalization. CQDs are fluorescent 0D carbon nanostructures with sizes below 10 nm. The fluorescence in CQDs originates from two sources, the fluorescence emission from bandgap transitions of conjugated p domains and fluorescence from surface defects. The CQDs can emit fluorescence in the near infrared (NIR) spectral region which makes them appropriate for biomedical applications. The fluorescence in these structures can be tuned with respect to the excitation wavelength. The CQDs have found applications in different areas such as biomedicine, photocatalysis, photosensors, solar energy conversion, light emitting diodes (LEDs) etc. The biomedical applications of CQDs include bioimaging, drug delivery, gene delivery, and cancer therapy. The fluorescent CQDs have low toxicity and other exceptional physicochemical properties in comparison to heavy metals semiconductor quantum dots (QDs) which make them superior candidates for biomedical applications. In this review, the synthesis routes and optical properties of the CQDs are clarified and recent advances in CQDs biomedical applications in bioimaging (in vivo and in vitro) drug delivery, cancer therapy, their potential to pass blood brain barrier (BBB) and gene delivery are discussed.
author_names: Mohammad Jafar Molaei
title: Carbon quantum dots and their biomedical and therapeutic applications: a review
year: 2019

abstract: Abstract Carbon quantum dots (CQDs) are emerging nanostructures which consist of carbon atoms and are typically below 10 nm in size. The CQDs are almost surface passivated or are functionalized with organics or biomolecules. CQDs have superior properties such as fluorescence emission, water solubility, cheap and easy synthesis methods, low toxicity, biocompatibility, easy functionalization, and chemical inertness. The CQDs have found versatile applications in different areas such as in vivo and in vitro bioimaging, drug delivery, gene delivery, sensors, solar energy conversion, photoelectrochemical (PEC) cells, photovoltaic solar cells, photocatalysis, and light emitting diodes (LEDs) CQDs could impart in photocatalytic reactions from two aspects; CQDs can be used alongside semiconductors as electron sink and could suppress electron hole recombination and also CQDs can generate electron hole pairs, as well. The CQDs with a wide spectral absorption and high absorption coefficients can enhance the photocatalytic activity. CQDs can also be used as sensitizers in the photoanode of solar cells. Due to the low cost and low toxicity of the CQDs in comparison to semiconductor quantum dots (QDs) they could be considered as potential alternatives in solar energy conversion applications. In this review, the CQDs are introduced and their optical properties are clarified. Recent advances of the CQDs in photocatalysis, PEC, and solar cells are reviewed.
author_names: Mohammad Jafar Molaei
title: The optical properties and solar energy conversion applications of carbon quantum dots: A review
year: 2020

abstract: Abstract As an efficient method to improve the intrinsic properties of carbon quantum dots (CQDs) doping CQDs with heteroatoms including nonmetallic atoms and metal ions recently receive great attention. Since the summary about the achievements of CQDs doping with nonmetallic atoms has been carried out. In this minireview, we will overview the state of the art knowledge of metal ions doped CQDs (M CQDs) The synthetic routes for M CQDs, the novel physicochemical properties originating from their unique morphology and constitute, and their applications in environmental, biological and energy related areas will be summarized and highlighted. The review aims to provide new insights into the exploration of the methods in order to improve the functionality of M CQDs, the relationship between newly novel physicochemical properties and metal ions doping, as well as their possible applications in future.
author_names: Liping Lin

Yaxin Luo

Pei-Chang Tsai

Jiajing Wang

Xi Chen
title: Metal ions doped carbon quantum dots: Synthesis, physicochemical properties, and their applications
year: 2018

abstract: As an emerging class of luminescent nanomaterials, carbon quantum dots (CQDs) have recently shown enormous potential for optoelectronic applications on account of their characteristic broad emission, tunable fluorescence emission, high thermal stability, and low cytotoxicity. In this review, we will update the latest research progress achieved in CQDs, including their synthesis, optical properties, luminescence mechanism, and applications in optoelectronics. Mainly reviewed here are their room temperature phosphorescence, delayed fluorescence properties, as well as their optoelectronic applications including light emitting diodes, lasing, solar cells, and photodetectors. Finally, current problems and challenges of CQD based optoelectronics applications are discussed with an eye on future development. We hope that this review will provide critical insights to inspire new exciting discoveries in the area of CQDs from both fundamental and practical standpoints so that the realization of their potential in the optoelectronic areas can be facilitated.
author_names: Ting Yuan

Ting Meng

Ping He

Yuxin Shi

Yunchao Li

Xiaohong Li

Louzhen Fan

Shihe Yang
title: Carbon quantum dots: an emerging material for optoelectronic applications
year: 2019

abstract: The emerging graphene quantum dots (GQDs) and carbon dots (C dots) have gained tremendous attention for their enormous potentials for biomedical applications, owing to their unique and tunable photoluminescence properties, exceptional physicochemical properties, high photostability, biocompatibility, and small size. This article aims to update the latest results in this rapidly evolving field and to provide critical insights to inspire more exciting developments. We comparatively review the properties and synthesis methods of these carbon nanodots and place emphasis on their biological (both fundamental and theranostic) applications.
author_names: Xin Ting Zheng

Arundithi Ananthanarayanan

Kathy Qian Luo

Peng Chen
title: Glowing graphene quantum dots and carbon dots: properties, syntheses, and biological applications.
venue: Small
year: 2015

abstract: Carbon quantum dots (CQDs) have emerged as a potential material in the diverse fields of biomedical applications due to their numerous advantageous properties including fluorescence, water solubility, biocompatibility, low toxicity, small size and ease of modification, inexpensive scale up production, and versatile conjugation with other nanoparticles. Thus, CQDs became a preferable choice in various biomedical applications such as nanocarriers for drugs, therapeutic genes, photosensitizers, and antibacterial molecules. Further, their potentials have also been verified in multifunctional diagnostic platforms, cellular and bacterial bio imaging, development of theranostics nanomedicine, etc. This review provides a concise insight into the progress and evolution in the field of CQD research with respect to methods/materials available in bio imaging, theranostics, cancer/gene therapy, diagnostics, etc. Further, our discussion is extended to explore the role of CQDs in nanomedicine which is considered to be the future of biomedicine. This study will thus help biomedical researchers in tapping the potential of CQDs to overcome various existing technological challenges.
author_names: Pooja Devi

Shefali Saini

Ki-Hyun Kim
title: The advanced role of carbon quantum dots in nanomedical applications.
venue: Biosensors bioelectronics
year: 2019