%0 Journal Article %J Nano Letters %D 2001 %T Observation of large changes in the band gap absorption energy of small CdSe nanoparticles induced by the adsorption of a strong hole acceptor %A Landes, Christy F. %A Braun, Markus %A Burda, Clemens %A El-Sayed, Mostafa A %X When butylamine In relatively high concentrations (0.1-0.25 M) is added to a colloidal solution of CdSe nanoparticles (NPs) that are approximately 1.6 nm in diameter, the band gap absorption changes from a broad, relatively weak absorption centered at 445 nm to a narrow, relatively strong absorption centered at 414 nm. The effect of concentration on the observed spectrum shows an isobestic point, suggesting an equilibrium between two species. The possible mechanisms for such a transformation are discussed. %B Nano Letters %V 1 %P 667-670 %8 Nov %@ 1530-6984 %G eng %M WOS:000173721800016 %R 10.1021/nl015619t