A study published in Nature describes a method for electrically activating lanthanide-doped insulating nanoparticles, a materials class commonly used for optical imaging but not previously compatible with low-voltage electronic devices. The work may be relevant for future diagnostic imaging and sensing systems that rely on stable near-infrared (NIR) light sources.
Lanthanide-doped nanoparticles (LnNPs) are known for producing narrow, stable emission in the second near-infrared window (NIR-II; 1,000–1,700 nm), a wavelength range useful for biomedical imaging and optical detection because of reduced tissue autofluorescence and scattering. However, these nanoparticles are electrical insulators, meaning they typically require optical excitation rather than electrical input.
The researchers addressed this limitation by creating hybrid nanoparticles in which LnNPs are coated with an organic molecule, 9-anthracenecarboxylic acid (9-ACA), which acts as a molecular antenna. Electrical charge recombination occurs on the organic component, generating excitons that transfer energy to the lanthanide ions. This indirect process allows lanthanide emission to be switched on electrically without requiring current to pass through the insulating nanoparticle itself.
Using this approach, the team built light-emitting diodes containing neodymium-, ytterbium-, or erbium-doped nanoparticles. The devices operated at low voltages (around 5 V) and produced narrow electroluminescence peaks at 976 nm, 1,058 nm, or 1,533 nm, depending on the lanthanide used. Emission bandwidths were substantially narrower than those seen in many semiconductor-based NIR emitters.
From a diagnostics perspective, these properties may be relevant for imaging or sensing platforms that require stable, wavelength-specific NIR light sources. The ability to tune emission wavelengths by changing the lanthanide dopant may also support multiplexed optical detection.
The study shows that triplet energy transfer from the organic ligand to the lanthanide ions is highly efficient and that device performance can be improved through nanoparticle and device design. While the work does not address clinical use, it demonstrates a route to electrically driven lanthanide emission that could inform future development of compact NIR light sources for diagnostic and analytical applications.
Newsletters
Receive the latest pathologist news, personalities, education, and career development – weekly to your inbox.
