Investigation of Two-Photon Absorption Properties in Branched Alkene and Alkyne Chromophores

✍ Scribed by Bhaskar, Ajit; Ramakrishna, Guda; Lu, Zhikuan; Twieg, Robert; Hales, Joel M.; Hagan, David J.; Van Stryland, Eric; Goodson, Theodore

• Book ID: 126150769
• Publisher: American Chemical Society
• Year: 2006
• Tongue: English
• Weight: 400 KB
• Volume: 128
• Category: Article
• ISSN: 0002-7863
• DOI: 10.1021/ja060630m

✦ Synopsis

Novel alkene and alkyne branched structures have been synthesized, and their two-photon absorption (2PA) properties are reported. This series of alkene and alkyne trimer systems tests the mechanistic approach for enhancing the 2PA process which is usually dictated by the pi-bridging, delocalization length, and corresponding charge transfer on the 2PA cross sections. The results suggest that alkene branched systems have higher 2PA cross sections. While steady-state absorption and emission measurements were not successful in predicting the observed trend of 2PA cross sections, time-resolved measurements have explained the trends observed. It was found that, upon photoexcitation, there is an ultrafast charge localization to an intramolecular charge-transfer (ICT) state, followed by the presence of a solvent and conformationally relaxed ICT state in these branched systems.