In this podcast episode, MRS Bulletin’s Elizabeth Wilson interviews postdoctoral researcher M. Iqbal Bakti Utama of Northwestern University about a method allowing single photon production without defect. Aryl diazonium chemistry has been used in the past to functionalize the surface of carbon nanotubes. Utama’s group found that this chemistry also works for tungsten diselenide surfaces. The group immersed tungsten diselenide monolayers into an aqueous solution of 4-nitrobenzene-diazonium tetrafluoroborate. The electrophilic molecules withdraws electrons from the monolayer, creating aryl diazonium radicals. These radicals react with each other to form nitrophenyl oligomer chains. Instead of binding covalently to the monolayer surface, the oligomers form an adlayer that is physisorbed on the tungsten diselenide surface. The spectra of photons generated when the research team irradiated the coated surface was vastly simpler than the uncoated monolayer. This work was published in Nature Communications.