Perovskite has broad application prospects in solar cells, light-emitting diodes (LEDs), and detectors due to its high luminescent efficiency and low cost. However, electrons and holes in traditional perovskite materials often struggle to effectively recombine and emit light. As a result, the strongly space-confined method is commonly employed to improve luminescence efficiency. Furthermore, how to enhance the brightness of LEDs and extend their lifespan has become a top research priority in this field.
In a study published in Nature, Prof. XIAO Zhengguo's team from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences has proposed a novel strategy based on weakly space-confined, large-grain crystals of all-inorganic perovskite to prepare perovskite films with larger crystalline grains and higher temperature resistance. Researchers increased the brightness of perovskite LEDs (PeLEDs) to over 1.16 million nits and extended their lifespan to more than 180,000 hours.
Researchers developed the strategy based on the weakly space-confined technique. They first added specific compounds—hypophosphorous acid and ammonium chloride—to the perovskite material. Then, they prepared a new type of perovskite thin film with larger crystalline grains and fewer defects using a high-temperature annealing process.
On the one hand, the annealing process suppressed non-radiative recombination (i.e., the process in which energy is lost without producing light) and significantly reduced ion migration. On the other hand, the new type of film avoided the defect problems associated with small crystals in traditional methods, greatly improving the stability and brightness of LEDs.
The new PeLEDs have a luminous efficiency exceeding 22%, which is already on par with that of commercial display products. They have a maximum brightness of 1.16 million nits, far exceeding the peak brightness of mainstream commercial LED screens, which typically reaches only several thousand nits. Moreover, the new PeLEDs are theoretically capable of operating for more than 180,000 hours at a normal brightness of 100 nits, meeting the standards of commercial LED products.
The novel strategy proposed in this study not only overcomes technical bottlenecks in the efficiency and stability of PeLEDs, but also holds great potential for their wide application in fields such as high-end display screens and ultra-high-brightness lighting.
