Challenges in Synthesizing Hexagonal Boron Nitride "Quantum" Dots

Fluorescent nanodots derived from hexagonal boron nitride (h-BN) have garnered significant attention over the past decade. As a result, various synthesis methods─encompassing both bottom-up hydrothermal reactions and top-down exfoliation processes─have been deemed "successful" in producing BN nanodots. Nevertheless, this Perspective emphasizes that substantial challenges remain in the synthesis of "true" nanodots composed mainly of h-BN units, as many so-called successful syntheses reported in the literature involve some mischaracterizations. Here, we highlight the crucial necessity for strict synthesis conditions to facilitate the production of authentic BN nanodots. Furthermore, it is imperative to re-evaluate the optical properties and photoluminescence mechanisms of these nanodots, entailing the establishment of clear criteria for what constitutes "true" BN nanodots.