The trapping dynamics of photogenerated electrons and holes in MoS2 nanoclu
sters has been studied using time resolved emission polarization and absorp
tion spectroscopies. These results are compared to absorption kinetics obta
ined on MoS2 nanoclusters with adsorbed DTDCI (DTDCI=diethylthiodicarbocyan
ine iodide) dye. The results indicate that emission from the MoS2 band edge
state is polarized, while emission from trapped electrons and holes is unp
olarized. This polarization difference is used to obtain the electron and h
ole trapping times and values of 275 ps and 42 ps, respectively, are obtain
ed. Decays having the same time constants are observed in the transient abs
orption results. The results obtained on the MoS2/DTDCI system show that el
ectron injection occurs with a time constant of 12 ps. These kinetics also
show a 225 ps decay component which is assigned to electron trapping and re
verse electron transfer. The 225 ps decay time along with the 275 ps trappi
ng time indicates that reverse electron transfer from the conduction band h
as a time constant of about 1.2 ns. Following trapping, reverse electron tr
ansfer from deep traps is slow. (C) 2000 American Institute of Physics. [S0
021- 9606(00)70337-0].