Size-dependent third-order optical nonlinearity in colloidal CdSe/CdS core/crown nanoplatelets with quasi-type Ⅱ band-structure

作者：Yang H.; Xiang W.; Zhao X.; Ge X.; Zhu B.^*; Cui Y.; Zhang J.

来源：Optics and Laser Technology, 2022, 156: 108615.

DOI：10.1016/j.optlastec.2022.108615

Colloidal semiconductor nanoplatelets, a kind of one-dimensional quantum confined materials, have been widely investigated due to their remarkable excitonic effect, in which excellent two-photon absorption property has been proved. In this work, 4.5 monolayers thick CdSe nanoplatelets laterally extended with CdS were synthesized and their crown size-dependent third-order nonlinear optical properties were measured through a picosecond Z-scan method. The detailed investigation combining the time-related photoluminescence spectroscopy reveals the effective passivation of the CdSe boundary with same area size of the core could improve the quantum yield up to 85% and third-order nonlinearity. In addition, the two-photon absorption cross-section can reach up to 6.8 × 106 GM due to the quasi-type Ⅱ band structure of these core/crown nanoplatelets.

• 单位
  南京师范大学; 河南大学; 中国科学院大学; 东南大学