Enabling Photon Upconversion and Precise Control of Donor-Acceptor Interaction through Interfacial Energy Transfer

Upconverting materials have achieved great progress in recent years, however, it remains challenging for the mechanistic research on new upconversion strategy of lanthanides. Here, a novel and efficient strategy to realize photon upconversion from more lanthanides and fine control of lanthanide donor-acceptor interactions through using the interfacial energy transfer (IET) is reported. Unlike conventional energy-transfer upconversion and recently reported energy-migration upconversion, the IET approach is capable of enabling upconversions from Er³⁺, Tm³⁺, Ho³⁺, Tb³⁺, Eu³⁺, Dy³⁺ to Sm³⁺ in NaYF₄- and NaYbF₄-based core-shell nanostructures simultaneously. Applying the IET in a Nd-Yb coupled sensitizing system can also enable the 808/980 nm dual-wavelength excited upconversion from a single particle. More importantly, the construction of IET concept allows for a fine control and manipulation of lanthanide donor-acceptor interactions and dynamics at the nanometer-length scale by establishing a physical model upon an interlayer-mediated nanostructure. These findings open a door for the fundamental understanding of the luminescence dynamics involving lanthanides at nanoscale, which would further help conceive new scientific concepts and control photon upconversion at a single lanthanide ion level.