Fig. 2.

Identifying the selenium decomposition product. a The experimental setup used to identify H₂Se as the gaseous selenium source. This panel was generated using templates in ChemDraw Professional 16.0. b The ⁷⁷Se NMR spectrum of H₂Se with TPPSe external standard. NMR characterization of TPPSe can be found in Supplementary Fig. 6. c Fluorescent CdSe nanocrystals under UV irradiation synthesized from the H₂Se generated in situ, the absorbance spectrum is in Supplementary Fig. 7