TY - JOUR T1 - Observation of large changes in the band gap absorption energy of small CdSe nanoparticles induced by the adsorption of a strong hole acceptor JF - Nano Letters Y1 - 2001 A1 - Landes, Christy F. A1 - Braun, Markus A1 - Burda, Clemens A1 - El-Sayed, Mostafa A AB - 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. VL - 1 SN - 1530-6984 N1 - Landes, C Braun, M Burda, C El-Sayed, MA M3 - 10.1021/nl015619t ER -