Three-photon absorption in seeded CdSe/CdS nanorod heterostructures
Ngiam, Song Wee
Sum, Tze Chien
Date of Issue2011
School of Physical and Mathematical Sciences
Size dependent three-photon absorption (3PA) and three-photon-excited photoluminescence (PL) of CdSe/CdS nanorod heterostructures have been investigated using Z-scan and upconversion PL techniques with 150-fs laser pulses at 1300 nm. The PL from these rods show clear cubic power dependence and the 3PA cross-section (σ3) was found to be as high as 1.5×10^(-75) cm^6s^2photon^(-2) for 39 nm long rods, which is two to four orders of magnitude larger than those previously reported for spherical semiconductor nanocrystals (NCs) under ~100 fs laser pulse excitation. Importantly, by exploiting the unique property of the seeded nanorods to exhibit strong quantum confinement even at relatively large rod sizes, a superlinear dependence of the 3PA cross-section on nanoparticle volume was found and validated over a wide volume range. A simple derived relation that quantitatively describes σ3 and takes into account the laser pulse duration, is proposed; thereby providing a clear basis of comparison between the σ3 values of various II-VI semiconductor nanomaterials and facilitating a more judicious choice of their use in 3PA applications.
The Journal of Physical Chemistry C
© 2011 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by The Journal of Physical Chemistry C, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1021/jp205238q ]