Trion Decay in Colloidal Quantum Dots

Using charged films of colloidal CdSe/CdS core/shell quantum dots of similar to 3.5 to 4.5 nm core diameters and 0.6 to 1.2 nm thick CdS shells, the radiative and nonradiative decay of the negatively charged exciton, the trion T-, are measured. The T- radiative rate is faster than the exciton by a factor of 2.2 +/- 0.4 and estimated at similar to 10 ns. The T- lifetime is similar to 0.7-1.5 ns for the samples measured and is longer than the biexciton lifetime by a factor or 7.5 +/- 1.7.