Boosting Applications with High-Performance Near-Infrared Phosphor-Converted Light-Emitting Diodes

Near-infrared (NIR) phosphor-converted (pc) light-emitting diodes (LEDs) are gaining popularity as smart NIR spectroscopy light sources. However, the low wall-plug efficiency (WPE) of NIR pc-LEDs has limited their applications due to the comprehensive properties of external quantum efficiencies (EQEs) and thermal stability for NIR phosphors. In this study, a simple strategy is presented to achieve high-performance NIR phosphors by breaking the d-d parity forbidden transitions of Cr3+ in the garnet host by introducing asymmetric vibrations via lattice distortions. The achieved EQE is as high as 44% at room temperature and maintains >98% of the initial EQE at 150 degrees C, demonstrating excellent thermal stability. Notably, these NIR phosphors enable unprecedented NIR pc-LEDs with a record WPE of 26% driven at 100 mA. Consequently, the application of NIR pc-LEDs is expanded to new areas such as real-time heart rate monitoring and fingerprint recognition.