The fast CT trion formation is possibly related with the reduced dimensionality at the molecule-TMD interface. The adsorbed Ru(DPPZ) 2 L-pro acts as a localized trap state for the ML-MoS 2 , rendering it locally as a 0-D system. The reduced dimensionality leads to a smaller exciton Bohr radius resulting in a larger trion binding energy and faster trion formation time. . Compared to the original trion in a 2-D MoS 2 system, the CT-trion form in a 0-D system experiences less screening, also increasing the CT trion formation rates. The blockage of the original trion formation suggests that doping with Ru(DPPZ) 2 L-pro changes the local electronic DOS of trions in MoS 2 , which was reflected by the suppression of the trion ESFG signal in Figure .