Overcoming lattice mismatch for core-shell NaGdF₄@CsPbBr₃ heterostructures.

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Core-shell heterostructures offer efficient energy transfer but are limited by lattice mismatch between components.
• Combining materials with different phases, such as lanthanide-doped nanoparticles (LnNPs) and lead halide perovskites (LHPs), presents significant challenges due to lattice incompatibility.

Purpose of the Study:

• To develop a strategy for growing α-phase LHPs onto β-phase LnNPs, overcoming the critical obstacle of lattice mismatch.
• To investigate the key factors influencing the successful formation of high-quality LnNP@LHP heterostructures.
• To demonstrate enhanced upconversion performance and two-way energy transfer within the synthesized heterostructures.

Main Methods:

• Utilized sub-8 nm LnNPs as seeds for the epitaxial growth of α-phase LHPs.
• Investigated the role of core size and reaction temperature in overcoming lattice mismatch.
• Characterized the resulting LnNP@LHP heterostructures to confirm their phase, morphology, and optical properties.

Main Results:

• Successfully synthesized LnNP@LHP core-shell heterostructures by overcoming lattice mismatch limitations.
• Demonstrated that sub-8 nm core size and high reaction temperature are critical for successful growth, rather than phase matching.
• Observed effective passivation of LnNP surface defects, leading to enhanced upconversion performance.
• Confirmed two-way energy transfer within the heterostructures.

Conclusions:

• The developed synthesis strategy effectively overcomes lattice mismatch challenges in heterostructure formation.
• Core size and reaction temperature are identified as crucial parameters for direct growth of dissimilar materials.
• The synthesized LnNP@LHP heterostructures show significant potential for applications in optoelectronics, anticounterfeiting, and light detection.