High-Resolution Optical Imaging and Sensing Using Quantum Emitters in Hexagonal Boron-Nitride

Abstract

Super-resolution microscopy has allowed optical imaging to reach resolutions well beyond the limit imposed by the diffraction of light. The advancement of super-resolution techniques is often an application-driven endeavor. However, progress in material science plays a central role too, as it allows for the synthesis and engineering of nanomaterials with the unique chemical and physical properties required to realize super-resolution imaging strategies. This aspect is the focus of this review. We show that quantum emitters in two-dimensional hexagonal boron nitride are proving to be excellent candidate systems for the realization of advanced high-resolution imaging techniques, and spin-based quantum sensing applications.

Intracellular biocompatible hexagonal boron nitride quantum emitters as single-photon sources and barcodes

“…Measuring single-photon correlations can reveal the presence of more sources whose centers are separated less than the diffraction Moreover, due to high photostability and broad spectral range of hBN color centers, they may be used to complement or replace standard fluorescent dyes used for instance in STED, STORM and single-molecule localization microscopy (SMLM). 12,38,39 In addition, spin-active defects in hBN were reported, serving as a platform for quantum, spin-based, sensing, for instance for ODMR. 35 Combining quantum singlephoton emission and superresolution imaging with sources embedded in the cellular interior is therefore a design that may in future lead to superior bioimaging.…”

“…hBN nanoparticles are increasingly used in different biological applications, ranging from nanocarriers and drug delivery systems, 23,32,33 biosensors, 34 optically detected magnetic resonance (ODMR), 35 cells and tissue imaging, 34,36 fluorescence staining and super-resolution imaging such as stimulated emission depletion microscopy (STED) and stochastic optical reconstruction microscopy (STORM). [37][38][39] However, the use of hBN color centers in biological tissues and live cells has not been studied and especially single photon emission from hBN color centers in the biological environment has not been demonstrated yet.…”

Color centers in wide-bandgap semiconductors for subdiffraction imaging: a review

“…A recent review on the potentials of hBN in SRM and the photophysics of CCs involved can be found in Ref. 26.…”

“…20 SiC and its nanostructures have also been studied as biological nanosensors, nanocarriers, and biomedical applications. [21][22][23] Other wide-bandgap materials, such as 2D hexagonal boron nitride (hBN), which have driven the attention in photonics and single-photon (SP) emission, 24,25 have also shown applicability to conventional super-resolution methods 26 due to a variety of functionalization options and low cells toxicity, 27,28 albeit only a few studies are available today. We will briefly assess the current state of the art of these three materials' CCs for their performance in SRM.…”

“…hBN emitters are from green to red and require excitation mostly at 532 nm or below; however, two-photon excitation with a 780-nm laser can be achieved in some emitters. Details of CCs in these materials can be found in a specific recent review, 11,15,26 whereas, here, the summary is done only of the centers used in SRM. Details of which properties are relevant for the specific SRM methods are discussed in the related sections of this paper.…”