We also observed quenching of the PL signal on the TPO graphene surface compared to SiO2 (Figure ). This is primarily attributed to Förster resonance energy transfer, enabled by the linear dispersion of Dirac electrons, which indicates a significant energy transfer between the Eu-BDC film and graphene. Alternatively, the quenching effect could be due to electron transfer. After excitation of the Eu 3+ , an excited electron can transfer to the graphene conduction band, leading to fluorescence quenching. Fluorescence quenching also affects the lifetime of Eu-BDC on graphene. We performed fluorescence lifetime imaging microscopy (FLIM) measurements to investigate the fluorescence dynamics of ALD/MLD Eu-BDC thin films on pristine and TPO graphene. While the overall fluorescence intensity (Figure ) was low upon 514 nm pulsed laser excitation, the lifetime of Eu-BDC on TPO areas was significantly longer than on pristine graphene (Figure ). The measured lifetime of ~2-3 ns is much shorter than the reported lifetimes for Eu 3+ films (~10 µs for transitions originating from the 5 D1 state and ~1.5 ms for transitions from the 5 D0 state). Lifetimes in the ns range could be explained by fluorescence quenching due to energy and charge transfer between graphene and Eu-BDC. We demonstrated that the fluorescence dynamics of uncoated graphene was not affected by the TPO process itself by performing FLIM measurements after UDLW (Figure S13a,b). No visible signal was detected when the surface was irradiated with the same fs-laser doses and measured under the same conditions as in Figure . However, other mechanisms, in addition to energy and electron transfer to graphene, might be involved, as short lifetimes were also observed for Eu-BDC thin films on SiO2 (Figure S13c,d). Notably, Eu-BDC demonstrates very weak absorption at the laser wavelengths used (514 and 532 nm). Therefore, the PL is expected to be much stronger upon resonant excitation in the UV range. The observed properties of Eu-BDC/graphene heterostructures could have potential applications in bioimaging, where tunable photoluminescence may enable precise tracking of biological processes in real time, and in solar cells, where enhanced electron transfer could improve charge separation efficiency.