Long-lived quantum-confined infrared transitions in CdSe nanocrystals

2019-11-11 04:50:54

infrared absorption nanocrystals CdSe dependent

责任者: Ginger, D.S.;Dhoot, A.S.;Finlayson, C.E.;Greenham, N.C. 单位: Cavendish Lab., Cambridge Univ., UK 来源出处: Applied Physics Letters(Appl. Phys. Lett. (USA)),2000/10/30,77(18):2816-18 摘要: We present quasi-steady-state photoinduced absorption measurements on thin films of CdSe nanocrystals dispersed in a polystyrene matrix. For nanocrystals treated with pyridine we observe an intense, size-dependent absorption peaking in the mid-infrared when the samples are irradiated with visible light. This infrared absorption is associated with a size-dependent bleach in the visible, near the peak of the first excitonic absorption. We attribute the infrared absorption to an intraband electron transition in the quantum dots and measure the lifetime of the absorbing state to be 1.0 ms at 295 K 关键词: cadmium compounds;II-VI semiconductors;infrared spectra;nanostructured materials;optical saturable absorption;semiconductor quantum dots;semiconductor thin films;visible spectra;long-lived quantum-confined infrared transitions;CdSe nanocrystals;quasisteady-state photoinduced absorption measurements;thin films;polystyrene matrix;pyridine;intense size-dependent absorption;midinfrared;visible light;infrared absorption;size-dependent bleach in the;first excitonic absorption;intraband electron transition;absorbing state lifetime;1.0 ms;295 K;CdSe