On October 16, 2023, Andrew Crowther, associate professor of chemistry, published a co-authored article in the journal Chemical Science, titled “Synthesis of graded CdS1−xSex nanoplatelet alloys and heterostructures from pairs of chalcogenoureas with tailored conversion reactivity.”
The research focuses on the synthesis and characterization of colloidal nanoplatelets composed of cadmium selenide and cadmium sulfide. Nanoplatelets are a type of two-dimensional nanoparticle that is only a few atoms thick, which has potential in luminescent display and solid-state lighting applications. The research was a collaborative project involving several research groups across multiple universities and was led by Professor Jonathan Owen and his graduate student Natalie Saenz in the Columbia University Department of Chemistry. Pure nanoplatelets, along with alloyed and core/crown heterostructures, were synthesized in a single step. Crowther investigated the atomic and vibrational structure of these samples using Raman spectroscopy, a sensitive probe of nanomaterial vibrations. Crowther found that alloyed nanoplatelets of varied composition have two characteristic Raman peaks, one for the cadmium-sulfur stretch vibration and one for the cadmium-selenide stretch vibration. These two peaks are characteristic of homogeneous alloys. Crowther also showed that Raman spectra can distinguish between a core/crown nanoplatelet with a sharp interface and one with a diffuse interface. This research advances the synthesis and characterization of nanoplatelet heterostructures.