Role of Structural Distortion in Stabilizing Electrosynthesized Blue-Emitting Phosphorene Quantum Dots

Abstract

Luminescent phosphorene quantum dots (PQDs) have emerged as fascinating nanomaterials for potential applications in optoelectronics, catalysis, and sensing. Herein, we investigate the structural distortion of black phosphorus (BP) under an applied electric field to yield blue luminescent PQDs [average diameter 8 ± 1.5 nm (N = 60)]. The electrosynthesized PQDs exhibit photoluminescence emission independent of excitation wavelength with 84% quantum efficiency. Structural distortion that occurred during the transformation of BP to PQDs is confirmed by results obtained during transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Further, using first-principles-based density functional theory, calculations on oxygenated and nonoxygenated PQDs augment the experimental observations that an optimum oxygen content maintains the structural integrity of PQDs, above which the structural robustness of PQDs is drastically diminished.

Abnormal Negative Thermal Quenching of Photoluminescence (PL) in Laser-Induced Exfoliated Black Phosphorus Quantum Dots for Applications as a Semiconductor PL Nanomaterial

“…The average size of the BPQDs was approximately 6 nm. The corresponding HRTEM images (Figure b,c) show the lattice parameters of 0.26 and 0.34 nm, which can be ascribed to the (040) and (021) planes of black phosphorus crystals, respectively. − The Raman spectrum of the BPQDs (Figure d) exhibits three typical vibrational peaks at 362.4, 437.1, and 464.5 cm –1 that usually correspond to the characteristic vibrations of a puckered hexagonal structure in bulk black phosphorus crystals. − These three Raman peaks are attributed to the A 1g , B 2g , and A 2g phonon modes, respectively. Both the HRTEM images and Raman spectrum of the BPQDs indicate that the BPQDs maintain their original puckered hexagonal structure.…”

Electrochemical transformation of black phosphorous to phosphorene quantum dots: effect of nitrogen doping

“…PQDs and NPQDs were synthesized from BP according to our previously reported single step electrochemical method as schematically represented in figure 1 [10,12]. Briefly, 50 μl of 2.0 mg ml −1 dispersion of BP (ACS materials) in deaerated ethanol was drop-dried on a 3 mm glassy carbon working electrode (GCE).…”

“…However, one limitation of this approach is poor yield, which can be overcome by employing large area electrode, increasing the reaction time etc. Accordingly, we reported a cathodic exfoliation of BP in a non-aqueous medium as a promising approach for pristine PQDs and NPQDs synthesis [10,12]. Oxidation induced edge state functionalization by P=O, P-O-P functional groups can be minimized by a reductive cleavage of P-P bonds (bond energy 200 kJ mol −1 ), enabling a rapid reconstruction of the edge states using solvation energy.…”

Plasma electrochemical synthesis of silicon quantum dots

“…When the dimensions of NCs are less than twice the Bohr radius of its constituent material, quantum confinement (QC) may occur [2]. Quantum dots are new nanomaterials with sizes small enough to induce the effect of QC [3], which have many advantages, such as size-dependent photoluminescence (PL), broad spectral distribution throughout the visible and infrared spectral regimes, and inherent photophysical stability [4][5][6][7]. It can be applied in optoelectric, photovoltaic and biomedical fields [8][9][10][11][12][13][14].…”