Energy transfer networks in doped fluoride nanocrystals

Designer optical nanomaterials hold promise for the design of emerging technologies aimed at converting and storing information. One key functionality of such nanosystems will be an ability to detect, convert, and amplify high energy signals into the visible range. Small systems with these properties could benefit applications including as sensors and detectors. Here, we design, synthesize and characterize two libraries of doped nanocrystals tailored for these functions. Our focus is on a downconversion energy transfer mechanism previously investigated for photon amplification in macroscopic crystal systems. Specifically, we study energy transfer in gadolinium fluoride host matrices with europium ion dopants. The work demonstrates how structural randomness in the host lattice can be leveraged as a design parameter to tune the scale and local connectivity of energy transfer networks. Spectroscopic measurements reveal conditions that enhance radiative emission via forbidden magnetic dipole transitions under broadband host lattice excitation. These findings suggest design strategies relevant for nanophotonic devices focused on achieving efficient information storage and transfer.