Breaking news: A collaboration between Princeton University and North Carolina State University has unveiled a breakthrough in converting low-energy light into higher-energy light, dramatically lowering the input power required for upconversion and opening new possibilities for displays and lighting.
Plasmon-boosted upconversion breaks energy barriers
The team advances triplet-fusion upconversion, a process in which energy from multiple molecules is harvested and re-emitted as photons with higher energy. Energy transfer involves temporarily elevating electrons to higher orbitals, with reactive collisions releasing the stored energy as blue or ultraviolet light. In liquids, this process thrives, but solids have proven harder because molecular excitations cannot move as freely. The latest approach aims to overcome this limitation.
Thin-film plasmonics amplify absorption
By harnessing plasmonics — the coupling of light to free electrons on a metal surface — the researchers concentrate light on a very thin film. Exposing a silver film to low-energy light generates surface plasmons that travel across the film and boost absorption by about tenfold compared with prior configurations. This heightened absorption increases the concentration of excited molecules and lowers the threshold light intensity needed to trigger upconversion, cutting input power by roughly 19 times relative to a non-plasmonic system.
From lab bench to real-world device
To demonstrate practicality, the researchers built an organic light-emitting diode. The plasmonic film produced blue light and, when combined with green and red light from the OLED, yielded white light. Blue OLEDs are challenging to operate because they demand high energy and can cause stability issues. The demonstration shows the potential of thin-film plasmonic technology to serve as a blue-light source without excessive energy input or specialized materials.
Team, students and funding
The project is led by a Princeton professor of electrical and computer engineering and the Andlinger Center for Energy and the Surroundings, with collaboration from North Carolina State University.Co-authors include Jesse Wisch, Kelvin Green, Amélie Lemay, Yiling Li, Tersoo Upaa Jr., hui Taou Kok and Seamus Lowe of Princeton, along with Evgeny Danilov and Felix Castellano of NC State. The research also mentored four Princeton undergraduates who contributed to the work. Support came in part from BioLEC, an Energy Frontier Research Center funded by the U.S. Department of Energy.
Published findings and implications
The team reported their findings in Nature Photonics on October 24, describing an ultralow-threshold, solid-state triplet-fusion upconversion enhanced by plasmonics. The study points to further improvements for white OLEDs through higher-performing films and optical structures.
| Key Facts | Details |
|---|---|
| Institutions | Princeton University; North Carolina State University |
| Lead Research | Barry Rand, Princeton |
| Technique | Plasmon-enhanced ultralow-threshold solid-state triplet fusion upconversion |
| Material | Thin silver film on which surface plasmons propagate |
| Absorption Boost | About 10× higher than non-plasmonic setups |
| Power Reduction | Approximately 19× lower input power required |
| Device Demonstration | Blue light generated and mixed with red/green to form white light |
| Publication | Nature Photonics, Oct.24 |
| Funding | BioLEC, DOE Energy Frontier Research Center |
Why this matters — evergreen view
Analysts say this plasmonic enhancement could reshape energy efficiency in lighting and portable displays. Lowering the power needs for blue light sources may lead to more stable, longer-lasting OLEDs and new architectural lighting options. Ongoing work will refine films and optical structures to maximize performance in real-world devices.
Next steps for this research
Researchers plan to optimize white OLED performance and explore advanced films and structures that could further boost efficiency and durability in consumer electronics.
Reader questions
1) Which applications do you envision for plasmon-enhanced upconversion in next-generation devices?
2) Do you think this approach can meaningfully reduce the energy footprint of blue-light sources in mainstream displays?
Share your thoughts in the comments, and stay tuned for ongoing coverage.
External references: Nature Photonics Article; Plasmonics Overview
