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Zhang T W, Hu K, Li G B, et al. Research progress in the quantum dots of nonmetals and their compounds prepared by ultrasonic method[J]. Opto-Electron Eng, 2024, 51(4): 230319. doi: 10.12086/oee.2024.230319
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Research progress in the quantum dots of nonmetals and their compounds prepared by ultrasonic method
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Abstract
Quantum dots (QDs), with diameters ranging from 1 to 20 nm, are zero-dimensional nanomaterials. They possess excellent optical properties, including size tunability, broad excitation spectra, high quantum efficiency, wide wavelength range, high photostability, and low photolysis. When the size of QDs approaches or becomes smaller than the exciton Bohr radius, the original material's continuous band structure undergoes quantization, leading to significant changes in properties and exhibiting outstanding optoelectronics performance. This review introduces the preparation methods of QDs, among which the ultrasonic method, as a common "top-down" method, is widely used because of its advantages of simple operation and environmental friendliness. Firstly, the mechanism and characterization techniques of non-metal and non-metallic compound QDs prepared by the ultrasonic method were prepared, and the effects of dispersants agent, ultrasonic power, and time on their size and morphology were analyzed. Subsequently, the application of non-metal and non-metallic compounds QDs prepared by the ultrasonic method in laser, solar cell, and other fields is discussed. The challenges and issues in current research are addressed, and personal perspectives and insights are provided. Finally, the prospect is given.-
Keywords:
- quantum dots /
- nanomaterials /
- ultrasonic method /
- non-metal /
- non-metallic compound
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References
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Overview
This review paper aims to provide a detailed introduction and summary of the research progress on the preparation of non-metal quantum dots (QDs) using the ultrasonic method, and explore their potential applications in various fields. QDs are nanomaterials with zero-dimensional structures, with grain diameters ranging from 1-20 nm. Compared to traditional materials, QDs exhibit a wide excitation spectrum, continuous distribution characteristics, symmetric and narrow emission spectra, tunable colors, high photostability, and resistance to photobleaching, making them highly attractive for applications in optoelectronic devices, solar cells, optical devices, sensors, and bioimaging. The paper first introduces the preparation methods of QDs, among which the ultrasonic method is a common "top-down" approach known for its simplicity and environmental friendliness. When the size of QDs approaches or is smaller than the exciton Bohr radius, the continuous band structure of the original material becomes quantized, resulting in significant changes in their properties. Subsequently, an overview of the research progress in the preparation of non-metal quantum dots using the ultrasonic method is presented, including the preparation methods and characterization techniques for different non-metal and non-metallic compound quantum dots. During the preparation process, the action of ultrasound, which involves the formation, growth, and collapse of bubbles, accompanied by intense shock waves, can produce small-sized nanoscale particles.
Through a review and analysis of related studies, the following conclusions are drawn: the ultrasonic method is an effective approach for the preparation of non-metal quantum dots, offering advantages such as simplicity, low cost, controllable size, environmental friendliness, and scalability. However, there are still challenges in current research, such as controlling the size and morphology of QDs and improving their luminescence efficiency and stability. Therefore, by optimizing the preparation process of the ultrasonic method, the stability and dispersibility of QDs can be further improved, facilitating their in-depth research and application in the field of nanomaterials.
In summary, the preparation of non-metal quantum dots using the ultrasonic method is a research area with potential and challenges. Through continuous research and exploration, along with the development of new materials, the application of new processes, and interdisciplinary collaborations, the ultrasonic method for QD preparation will have broader prospects, providing new opportunities and breakthroughs for the development of optoelectronics, energy, and biomedical fields.
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Zhang T W, Hu K, Li G B, et al. Research progress in the quantum dots of nonmetals and their compounds prepared by ultrasonic method[J]. Opto-Electron Eng, 2024, 51(4): 230319. doi: 10.12086/oee.2024.230319
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Figure 1.
Mechanism diagram of G QDs prepared by the ultrasonic method
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Figure 2.
Preparation and characterisation of BP QDs. (a) and (b) TEM and HRTEM images of the BP QD, respectively [62]; (c) FFT pattern of the white highlights in (b) [62]; (d) , (e) and (f) are the SEM and TEM images of BP QDs/PLGA NSs and the absorption spectra dispersed in PBS for 0 h, 24 h and 8 weeks, respectively[32]; (g) and (h) are the pictures of BP QDs (Ⅰ) and PEG modified (Ⅱ) in water or PBS solution, respectively, and the absorption spectra of different concentrations of PEG modified BP QDs dispersed in water solution[37]; (i) Ultraviolet visible absorption spectrum of BP QDs[65]
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Figure 3.
Preparation and characterization of elemental semiconductor QDs. (a) Schematic diagram of G QDs prepared by ultrasonic stripping [50]; (b) Ultraviolet-visible absorption spectra of G QDs[45]; (c) Photoluminescence spectra and excitation spectra at different excitation wavelengths[45]; (d) and (e) are TEM and HRTEM images of C QDs, respectively[35]; (f) The UV-visible absorption spectrum of CQDs dispersion along with non-sonicated acetonitrile as solvent background[35]; (g) Photographs of C QDs fluorescence excited at different excitation wavelengths[35]; (h) and (i) are HRTEM image and UV-vis absorption spectra of B QDs, respectively[44]
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Figure 4.
Preparation and characterization of nonmetallic compounds QDs. (a) Schematic diagram of BN QDs preparation[73]; (b) Ultraviolet-visible absorption (black), PLE (red) and PL (blue) spectra of BN QDs[71]; (c), (d) and (e) are the ultraviolet-visible absorption spectra of organic solvents dispersed in ethanol, DMF, and NMP, respectively[70]; (f) Ultraviolet-visible absorption and emission spectra of OCNQDs[75]; (g) Ultraviolet-visible absorption spectra of BCNO QDs[76]; (h) and (i) are the Ultraviolet-visible spectra of g-C3N4 QDs and the relationship between PL intensity and UV illumination time, respectively[77]
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Figure 5.
Applications of QDs lasers. (a) Configuration of the pulsed laser or ultrashort pulsed laser based on GR-BP[55]; (b) and (c) are output power and pulse energy as pump power functions, and output repetition rate and pulse duration as pump power functions, respectively[55]; (d) Schematic diagram of ultrafast Erbium-doped fiber laser based on microfiber P QD-SA[47]; (e) and (f) are optical spectra and soliton spectra, respectively[47]; (g) Experimental diagram of all-optical active Q-switched lasers based on B QDs[61]; (h) and (i) are the state and output spectra of CW and Q-switched pulse lasers, respectively[61]
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Figure 6.
Optoelectronic device applications of QDs. (a) OPV device structure on the ITO glass substrate[63]; (b) and (c) are the UV visible absorption spectra and PL spectra of BP QDs under different size conditions, respectively[63]; (d) and (e) are respectively the J-V characteristic curves and EQEs measurements of OPVs with different concentrations of BP QD[63]; (f) and (g) are respectively the device structure diagram of p-i-n plane HPSC and the energy level diagram of each layer in the device[64]; (h) SEM diagram of the HPSCs structure[64]; (i) J-V characteristic curve of HPSCs with and without BP QDs interlayer[64]
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