Enhanced tunability of the multiphoton absorption cross-section in seeded CdSe/CdS nanorod heterostructures

• Main Authors: Xing, Guichuan, Chakrabortty, Sabyasachi, Chou, Kok Loong, Nimai Mishra, Huan, Alfred Cheng Hon, Chan, Yinthai, Sum, Tze Chien
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Materials::Microelectronics and semiconductor materials
• Online Access: https://hdl.handle.net/10356/94162; http://hdl.handle.net/10220/7022
• Institution: Nanyang Technological University

We present a method to separately tune the multiphoton absorption (MPA) and multiphoton excited photoluminescence using semiconductor core/enlarged-shell quantum dots (QDs), where the enlarged shell greatly enhances the MPA cross-sections while varying the core size facilitates emission wavelength selectivity. Following two-photon absorption (2PA) primarily in the shell and ultrafast charge-carrier localization to the core, luminescence occurs. We exemplify the validity of this method with CdSe/CdS nanorod heterostructures and find that the 2PA cross-section is enlarged to ∼ 1.4×10^6 GM for 180 nm nanorods (with 800 nm, 150 fs laser pulse excitation) which is two to four orders larger than that of CdSe QDs.