Dominant role of surface states in photoexcited carrier dynamics in CdSe nanocrystalline films prepared by chemical deposition

We report on ultrafast carrier dynamics in nanocrystalline CdSe thin films prepared by chemical solution deposition. The photoluminescence and transient absorption dynamics have spectrally dependent decay faster at shorter wavelengths. The spectral behavior of the decay rates in samples with different nanocrystal sizes and the sensitivity of the dynamics on the surface modification indicate the dominant role of the surface states in the photoluminescence. (C) 2000 American Institute of Physics. [S0003-6951(00)04741-0].