Nonlinear spectroscopy of oxidised CuInS2 nanocrystals

The pump-and-probe method was used in the picosecond range to study nonlinear absorption in oxidised CuInS₂ nanocrystals (of 3 nm radius) embedded in a polymer film. Oxidation gave rise to an additional absorption band with its maximum at 1.03 eV. This band was bleached by excitation with laser pulses of the 1.08 μm wavelength. Fast (~50 ps) capture of carriers by deep trapping states resulted in long-lived (in excess of 300 ps) bleaching and induced absorption. An energy level diagram was proposed for oxidised CuInS₂ nanocrystals.