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Direct carbonization of organic solvent toward graphene quantum dots
摘要： The bottom-up synthesis of graphene quantum dots (GQDs) using solvothermal method has attracted considerable attention because of their fewer defects and controllable size/ morphology. However, the influence of organic solvent on the preparation of GQDs is still unknown. Herein, a systematic study about carbonization of organic solvents toward GQDs is reported. Results show that organic solvent with the double bond or benzene ring or double hydrophilic groups could be directly decomposed into GQDs without the addition of catalysts or molecule precursors. The as-synthesized GQDs demonstrate ultra-small size distribution, high stability, and excitation wavelength-tunable and upconverted fluorescence. Both hematological and histopathological analyses studies show that the as-synthesized GQDs demonstrate a much good safety profile and excellent biocompatibility. The versatility of this synthetic strategy allows easy control of the surface group, composition, and optical properties of GQDs at the molecular level.
关键词： organic solvents,biocompatibility,fluorescence,graphene quantum dots,solvothermal synthesis
更新于2025-09-23 15:21:01
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Investigation of the Effects of Various Organic Solvents on the PCBM Electron Transport Layer of Perovskite Solar Cells
摘要： In this study, four organic solvents including 1,2-dichlorobenzene (DCB), chlorobenzene (CB), methylbenzene (MB), and chloroform (CF) were used as solvents in the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) electron transport layer (ETL) of perovskite solar cells (PSCs). This study observed the effects of various solvents on the surface morphology of the ETL by using an optical microscope (OM) and scanning electron microscope (SEM). The surface roughness, crystal structure, and surface element bonding of the ETL were observed using an atomic force microscope (AFM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscope (XPS), respectively. The absorption spectrum of the perovskite layer was explored using an ultraviolet-visible (UV-Vis) spectrometer. The characteristics of the PSC device were analyzed in terms of its current density–voltage (J–V) curve, external quantum efficiency (EQE), and electrochemical impedance spectroscopy (EIS) measurements. The results showed that DCB is a solvent with a high boiling point, low vapor pressure, and high dielectric constant, and using DCB as the solvent for ETL, the uniformity, coverage, and surface roughness of the ETL showed better properties. The power conversion efficiency of the PSC in which DCB was used as the solvent achieved a value of 11.07%, which was higher than that of the PSCs in which other solvents were used.
关键词： organic solvents,perovskite solar cells,1,2-dichlorobenzene,electron transport layer
更新于2025-09-23 15:19:57
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An Unexpected Transformation of Organic Solvents into 2D Fluorescent Quantum Dots During Ultrasonication Assisted Liquid Phase Exfoliation
摘要： Ultrasonication within organic solvents is widely used to exfoliate layered materials and produce two-dimensional (2D) nanostructures. Several 2D materials synthesized by such liquid phase exfoliation (LPE) approaches are reported to exhibit photoluminescence. In these approaches, it is presumed that while the 2D nanostructures are derived from the layered parent material undergoing delamination, the organic solvent serves as a dispersing medium. However, in this study, we show that the organic solvent also contributes towards formation of 2D nanostructures that are optically active. We show that that bare organic solvent, when exposed to ultrasonication, transforms into 2D photoluminescent carbon quantum dots (CQDs) that display blue, cyan, green, and yellow emissions depending upon the excitation wavelength. Although this finding is intuitive, it has remained unacknowledged in the design of experiments which require ultrasonication of layered materials in organic solvents. Our results suggest that optical properties of dispersions obtained by LPE embody a contribution not only from the 2D nanostructures derived from the layered material but also from the 2D CQDs that are formed as a natural result of the liquid medium being exposed to ultrasonication. We anticipate that this new physical insight would form an important addition to the guidelines for exfoliation and help in rightly inferring the optical properties of the 2D material dispersions produced by these methods.
关键词： 2D nanostructures,Carbon quantum dots,Organic solvents,Liquid phase exfoliation,Ultrasonication,Photoluminescence
更新于2025-09-11 14:15:04
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Optically oriented attachment of nanoscale metal-semiconductor heterostructures in organic solvents via photonic nanosoldering
摘要： As devices approach the single-nanoparticle scale, the rational assembly of nanomaterial heterojunctions remains a persistent challenge. While optical traps can manipulate objects in three dimensions, to date, nanoscale materials have been trapped primarily in aqueous solvents or vacuum. Here, we demonstrate the use of optical traps to manipulate, align, and assemble metal-seeded nanowire building blocks in a range of organic solvents. Anisotropic radiation pressure generates an optical torque that orients each nanowire, and subsequent trapping of aligned nanowires enables deterministic fabrication of arbitrarily long heterostructures of periodically repeating bismuth-nanocrystal/germanium-nanowire junctions. Heat transport calculations, back-focal-plane interferometry, and optical images reveal that the bismuth nanocrystal melts during trapping, facilitating tip-to-tail “nanosoldering” of the germanium nanowires. These bismuth-semiconductor interfaces may be useful for quantum computing or thermoelectric applications. In addition, the ability to trap nanostructures in oxygen- and water-free organic media broadly expands the library of materials available for optical manipulation and single-particle spectroscopy.
关键词： bismuth-nanocrystal/germanium-nanowire junctions,organic solvents,optical traps,photonic nanosoldering,nanoscale metal-semiconductor heterostructures
更新于2025-09-11 14:15:04