Share Email Print

Proceedings Paper

Quantifying energy transfer in semiconductor nanocrystals using coherent phonon manipulation and ultrafast spectroscopy (Presentation Recording)
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

One potential way to increase photovoltaic efficiency is to take advantage of hot-carriers. Nanocrystal based solar cells aim to take advantage of hot-carrier capture to boost device performance. The crucial parameter for gauging a given nanocrystal material for this application is the electron-phonon coupling. The electron-phonon coupling will dictate the thermalization time of hot-carriers. In this study we demonstrate a method of quantifying the electron-phonon coupling in semiconductor nanocrystals. By employing ultrafast transient absorption spectroscopy with temporal pulse shaping, we manipulate coherent phonons in CdTe_{1-x}Se_{x} nanocrystals to quantify the efficiency of the electron-phonon coupling. The Raman active longitudinal optical phonon (LO) modes were excited and probed as a function of time. Using a temporal pulse shaper, we were able to control pump pulse pairs to coherently excite and cancel coherent phonons in the CdTe_{1-x}Se_{x} nanocrystals, and estimate the relative amount of optical energy that is coupled to the coherent CdSe LO mode which is the dominant thermalization pathway for the hot-electrons in this system.

Paper Details

Date Published: 5 October 2015
PDF: 1 pages
Proc. SPIE 9562, Next Generation Technologies for Solar Energy Conversion VI, 956206 (5 October 2015); doi: 10.1117/12.2186831
Show Author Affiliations
Bryan T. Spann, U.S. Naval Research Lab. (United States)
Purdue Univ. (United States)
Xianfan Xu, Purdue Univ. (United States)

Published in SPIE Proceedings Vol. 9562:
Next Generation Technologies for Solar Energy Conversion VI
Oleg V. Sulima; Gavin Conibeer, Editor(s)

© SPIE. Terms of Use
Back to Top