Suppressing the photobleaching and photoluminescence intermittency of single near-infrared CdSeTe/ZnS quantum dots with p-phenylenediamine

Abstract

Intrinsic photobleaching and photoluminescence (PL) intermittency of single quantum dots (QDs), originating from photo-oxidation and photo-ionization respectively, are roadblocks for most single-dot applications. Here, we effectively suppress the photobleaching and the PL intermittency of single near-infrared emitting QDs with p-phenylenediamine (PPD). The PPD cannot only be used as a high-efficient reducing agent to remove reactive oxygen species around QDs to suppress the photo-oxidation, but can also bond with the surface defect sites of single QDs to reduce electron trap states to suppress the photo-ionization. It is shown that the survival time of single QDs, the on-state probability of PL intensity traces, and the total number of emitted photons are significantly increased for single QDs in PPD compared with that on glass coverslip.

Highly Polarized Single Photons from Strain-Induced Quasi-1D Localized Excitons in WSe2

“…Photobleaching is absent during the covered 30 min time span for the used experimental conditions: a vacuum environment ∼10 –5 mbar and laser excitation power of 0.5 μW. 29 − 31 The emission peak also survives multiple thermal cycles between room temperature and liquid helium temperature and remains around 1.704 eV. Jitter, characteristic for some localized excitons, is indeed present.…”

Comparison of back focal plane imaging of nitrogen vacancy centers in nanodiamond and core-shell CdSe/CdS quantum dots

“…It was observed, that under our experimental conditions (irradiative power > 50 μW) some of the quantum dots bleached out. This bleaching could be caused by photo-oxidation reactions that lead to a decomposition of the quantum dot [15]. Scans of the sample before and after measuring the singlephoton purity of some emitters are shown in Figure 5.…”

“…The inverse tangent function has a quadrant correction in the Euclidean plane, from which the following correction of the calculated in-plane angles are derived. If the conditions in equations ( 14) or ( 15) are true, the values of φx (14) or φy (15) need to be corrected as shown in equation ( 16) [7].…”

Advances in the Methods for the Synthesis of Carbon Dots and Their Emerging Applications

“…Meanwhile, fluorescent carbon (CD) dots with size parameters, water solubility, lightfastness, especially high levels of biocompatibility and low toxicity have generated worldwide interest in disciplines such as bioimaging, analysis and gene therapy [ 20 ]. According to such properties, this new kind of nanoparticle (NP) outperforms quantum dots (high toxicity problems) [ 21 ] and conventional dyes (photobleaching) [ 22 ]. The most recent application of CDs is in the field of chemical warfare agents, especially for the detection of hazardous chemicals.…”