Large unilamellar vesicles (100 nm) were functionalised to obtain supramolecular particles capable of light upconversion in pure aqueous media. Triplet–triplet annihilation of diphenylanthracene (DPA) leading to delayed fluorescence at 420 nm was used to up-convert the light absorbed by embedded metal complex sensitisers. The lipid type and the chromophore position in the membrane affect the TTA intensity, which remains constant over a large concentration range.