Elucidating the role of oxidation in two-dimensional silicon nanosheets

We report a synthetic protocol that yields hydrogen-terminated 2D silicon nanosheets with greatly reduced siloxane (e.g., Si–O–Si, O_xSi) content. These nanosheets displayed weak, broad photoluminescence centered near 610 nm with a low absolute photoluminescence quantum yield (as low as 0.2%). By intentionally oxidizing the nanosheets, the photoluminescence peak emission wavelength blueshifted to 510 nm, and the quantum yield increased by more than an order of magnitude to 8.5%. These results demonstrate that oxidation of 2D silicon nanosheets modulates the material's bandgap and suggests that previously reported photoluminescence properties for this material resulted, in part, from oxidation.. Authors: Essner, Jeremy B. [Iowa State Univ., Ames, IA (United States)] (ORCID:0000000225007968); Bera, Abhijit [Iowa State Univ., Ames, IA (United States)] (ORCID:0000000274805245); Jabrayilov, Maharram [Iowa State Univ., Ames, IA (United States)] (ORCID:000000020080280X); Chaudhari, Abhishek [Iowa State Univ., Ames, IA (United States)] (ORCID:0000000178318105); Diroll, Benjamin T. [Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000334880213). DOE Contract: AC02-06CH11357