Light-emitting diodes (LEDs) are crucial for modern display technology, needing to meet the Rec. 2020 color gamut standard for next-generation applications. Metal-halide perovskites, known for their narrowband emissions and easily tunable bandgaps, are among the few emitters capable of fully meeting Rec. 2020 standards. Significant progress in perovskite LEDs (PeLEDs) has been achieved recently, with their current external quantum efficiency (EQE) nearing 30%, rivaling commercial organic LEDs (OLEDs). However, the inherent instability of perovskites remains a challenge for practical use. Combining perovskite emitters with established technologies like OLEDs could be a viable path towards commercializing high-definition displays.
A recent study published in Light Science and Applications details the work of a research team led by Professor Xuyong Yang from the Key Laboratory of Advanced Display and System Applications of the Ministry of Education at Shanghai University, China. The team has developed a stable, efficient, and high-color purity hybrid LED with a tandem structure by merging perovskite LED and commercial OLED technologies, aiming to speed up the practical use of perovskites. By selecting PeLED and OLED with similar photoluminescence peaks, they optimized photon emission and minimized photon reabsorption, resulting in narrower emission spectra. The team designed an efficient interconnecting layer with p-type interface doping to ensure good opto-electric coupling and reduce Joule heating. The resulting green-emitting hybrid LED features a narrow line width of approximately 30 nm, a peak luminance exceeding 176,000 cd/m, a maximum EQE surpassing 40%, and an operational half-lifetime of over 42,000 hours.
Research Report:Efficient and stable hybrid perovskite-organic light-emitting diodes with external quantum efficiency exceeding 40 per cent
