| Autor: |
Koscher BA; Department of Chemistry, University of California Berkeley , Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.; Kavli Energy NanoScience Institute, University of California Berkeley and Lawrence Berkeley National Lab , Berkeley, California 94720, United States., Swabeck JK; Department of Chemistry, University of California Berkeley , Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.; Kavli Energy NanoScience Institute, University of California Berkeley and Lawrence Berkeley National Lab , Berkeley, California 94720, United States., Bronstein ND; Department of Chemistry, University of California Berkeley , Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.; Kavli Energy NanoScience Institute, University of California Berkeley and Lawrence Berkeley National Lab , Berkeley, California 94720, United States., Alivisatos AP; Department of Chemistry, University of California Berkeley , Berkeley, California 94720, United States.; Department of Materials Science and Engineering, University of California Berkeley , Berkeley, California 94720, United States.; Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.; Kavli Energy NanoScience Institute, University of California Berkeley and Lawrence Berkeley National Lab , Berkeley, California 94720, United States. |
| Abstrakt: |
We demonstrate postsynthetic modification of CsPbBr 3 nanocrystals by a thiocyanate salt treatment. This treatment improves the quantum yield of both freshly synthesized (PLQY ≈ 90%) and aged nanocrystals (PLQY ≈ 70%) to within measurement error (2-3%) of unity, while simultaneously maintaining the shape, size, and colloidal stability. Additionally, the luminescence decay kinetics transform from multiexponential decays typical of nanocrystalline semiconductors with a distribution of trap sites, to a monoexponential decay, typical of single energy level emitters. Thiocyanate only needs to access a limited number of CsPbBr 3 nanocrystal surface sites, likely representing under-coordinated lead atoms on the surface, in order to have this effect. |
