Upscaling Colloidal Nanocrystal Hot-Injection Syntheses via Reactor Underpressure

We report an approach to linearly upscale hot-injection syntheses of colloidal nanocrystals by applying mild underpressure to the flask reactor prior to the injection such that rapid addition of large volumes of the precursor is facilitated. We apply this underpressure-assisted approach to successfully upscale synthetic protocols for metallic (Sn) and semiconductor (PbS, CsPbBr₃, and Cu₃In₅Se₉) nanocrystals by 1–2 orders of magnitude to obtain tens of grams of nanocrystals per synthesis. Here, we provide the technical details of how to perform underpressure-assisted upscaling and demonstrate that nanocrystal quality is maintained for the large-batch syntheses by characterizing the size, size distribution, composition, optical properties, and ligand coverage of the nanocrystals for both small- and large-scale syntheses. This work shows that fast addition of large injection volumes does not intrinsically limit upscaling of hot-injection-based colloidal syntheses