Efficient vacuum ultraviolet light frequency downconversion by thin films of CdSe quantum dots

Frequency downconversion is an effective method for the detection of ionizing radiation. We demonstrate the utilization of thin films of chemically synthesized CdSe quantum dots for this purpose. A high quantum yield of similar to 0.2 is obtained at room temperature, which does not depend on the excitation wavelength in the range from 32 to 114 nm. The measured decay time is short, in the nanosecond regime, and the visible light output is stable. A significant advantage of such semiconductor quantum dots is the potential to tune the emission wavelength via selection of the nanoparticle size. (c) 2006 American Institute of Physics.