Plasmonic Semiconductor Nanoparticles in a Metal–Organic Framework Structure and Their in Situ Cation Exchange

Composites of nanoparticles (NPs) in metal–organic frameworks (MOFs) combine the versatile properties of NPs with the defined porosity of MOFs. Here, we show the encapsulation of plasmonic semiconductor NPs in ZIF-8 crystals. Both p-type and n-type doped plasmonic semiconductor NPs (consisting of Cu2–xSe and indium tin oxide, respectively) are encapsulated. The plasmonic and structural properties of each system are preserved during the formation of the composites. Furthermore, we demonstrate the accessibility of the NPs integrated in ZIF-8 via the successful first-time in situ cation exchange of MOF-embedded Cu2–xSe NPs to HgSe NPs and Ag2Se NPs. This ion exchange occurs without influencing the composition or structural integrity of the metal–organic framework. This approach hence allows a fixation of plasmonic nanoparticles avoiding strong plasmon–plasmon coupling but still keeping the plasmonic nanoparticles accessible.