Researchers at the Hong Kong University of Science and Technology (HKUST) School of Engineering have developed what they claim to be the world’s brightest and most energy-efficient quantum rod LEDs (QRLEDs). These next-generation QRLEDs feature optimized deep green emission at the top of the color triangle, enabling displays with unprecedented color purity and maximized color gamut, the researchers said. Boasting a longer lifespan and triple the brightness of previous models, the technology delivers energy-efficient, ultra-vivid visuals for smartphones, televisions, and AR/VR devices while further enhancing color performance. A group photo of Abhishek K. Srivastava (first row, center), Maksym Prodanov (first row, second right) and Ph.D. candidate Kumar Mallem (first row, second left) with members of their research team. Prodanov holds three bottles with quantum rod materials while Mallem holds a green-emitting quantum rod LED (QRLED) sample. Courtesy of Hong Kong University of Science and Technology. LEDs have been widely used in electronic products for decades. Recent advancements in quantum materials have given rise to quantum dot LEDs (QLEDs) and QRLEDs. Both offer narrow emission bandwidths and high color purity, surpassing traditional LEDs. Among these, QRLEDs excel with higher light outcoupling efficiency. However, QRLEDs face challenges: Their green emission underperforms QLEDs due to inefficient charge injection, electron leakage at interfaces, and structural barriers including thick insulating shells and long organic ligands (molecules attached to surface of a nanorod) that hinder charge transport and stability. To tackle these problems, a team led by Abhishek Srivastava, associate professor at the department of electronic and computer engineering, innovated a class of green-emitting quantum rods featuring a customized core-gradient alloy structure with minimized outer shell thickness. This design achieves highly bright deep green emission (515 to 525 nm) at the peak of the color triangle, maximizing display color gamut. The team also engineered rods with uniform, smooth morphology and shorter length, enabling dense, void-free film packing. Further innovations include shorter organic ligands, a bilayer hole transport layer, collectively enhancing charge balance and suppressing electron leakage to boost efficiency and stability. “We have successfully developed remarkably efficient and bright green-emitting QRLEDs by precisely designing the quantum rod composition, morphology, shape, and ligand structure, alongside the rational engineering of the device’s hole transport layer,” said Srivastava, corresponding author of the paper. The newly developed QRLEDs provide 24% external quantum efficiency, compared to older models’ 22% external quantum efficiency. Additionally, the QRLEDs produce 89 cd A?¹ (candelas per ampere), which outperforms all existing QRLEDs. The green LEDs are able to shine 3× brighter than previous versions. The QRLEDs also boast operational stability exceeding 22,000 h, positioning the technology for commercial display applications. “Our work demonstrates that meticulous control over nanorod composition and interface engineering can lead to disruptive advances in optoelectronic performance. This paves the way for high-resolution, energy-efficient displays with unprecedented brightness and longevity,” said Srivastava. The research was published in Advanced Materials (www.doi.org/10.1002/adma.202503476).