Engineering Full-Spectrum Upconversion Through Coherent Energy Recycling in NaYF₄:Yb,Tm/Cs₄PbBr₆ Heterostructure

Area of Science:

• Materials Science
• Nanotechnology
• Photonics

Background:

• Hybrid heterostructures of lanthanide-doped upconversion nanoparticles (UCNPs) and lead-halide perovskites (LHPs) show promise for advanced luminescence and photon conversion.
• Challenges include synthesizing well-defined UCNP/LHP structures due to perovskite crystallization and understanding energy transfer mechanisms.

Purpose of the Study:

• To develop a controllable synthesis method for high-quality UCNP/LHP heterostructures.
• To elucidate the role of LHPs in modulating upconversion processes.

Main Methods:

• A thermodynamics-controlled epitaxial growth strategy was employed.
• Fabrication of NaYF4:Yb,Tm/Cs4PbBr6 heterostructures with tunable architectures (core/shell to UCNP-in-LHP solids).

Main Results:

• High-quality NaYF4:Yb,Tm/Cs4PbBr6 heterostructures were successfully synthesized.
• The Cs4PbBr6 layer was shown to actively participate in energy transfer, facilitating back energy transfer to Tm3+ and enabling coherent energy recycling.
• Broadly tunable upconversion emission across the visible spectrum was achieved.

Conclusions:

• A robust method for fabricating high-quality UCNP/LHP heterostructures was established.
• Lead-halide perovskites function as active components in engineering upconversion pathways, not just passive acceptors.