Stanford University researchers have taken significant strides in improving the performance of perovskite LEDs (PeLEDs), a more cost-effective alternative to traditional LEDs. PeLEDs offer the potential for energy-efficient indoor lighting and enhanced color purity in electronic displays. However, their drawbacks, such as short lifespan and lower energy efficiency, have hindered their commercial viability thus far.

Eight green manganese-doped perovskite LEDs in Congreve’s lab glow as researchers run an electric current through them. (Image credit: Sebastian Fernández)

The manufacturing process for traditional LEDs, with their complex and costly semiconductor production, has been a stumbling block. In contrast, PeLEDs utilize metal halide perovskites, which can be grown on glass substrates or dissolved in solution for simpler production. This cost-saving advantage has made PeLEDs an attractive option for widespread adoption in various applications.

To address the issue of defects in the atomic structure of perovskites, which hampered efficiency and durability, the Stanford researchers implemented innovative techniques. By replacing some of the lead atoms with manganese, they succeeded in more than doubling the brightness, nearly tripling the efficiency, and extending the lifespan of PeLEDs. However, this breakthrough came at the expense of reduced performance over time.

In addition to the lead-manganese substitution, the researchers explored the use of phosphine oxide additives. This addition significantly improved the efficiency of PeLEDs, making them up to five times more energy-efficient than the manganese-enhanced counterparts. However, the trade-off was a rapid decline in brightness.

The Stanford team is now focused on understanding and mitigating these trade-offs to achieve a commercially viable solution. Further experimentation with different phosphine oxide additives aims to uncover a more stable formulation that balances efficiency and durability.

The researchers are not stopping there. They are also addressing other limitations of PeLEDs, such as the challenge of producing violet and ultraviolet light. By introducing water into the solution during perovskite crystal formation, they successfully generated PeLEDs that emit vibrant violet light with five times the efficiency. This breakthrough opens up new possibilities for using ultraviolet PeLEDs in medical equipment sterilization, water purification, and indoor crop cultivation, all at a more affordable cost compared to existing LED technologies.

These advancements in PeLEDs demonstrate the ongoing efforts to overcome the obstacles hindering their widespread adoption. While challenges remain, the potential for energy-efficient lighting and improved color reproduction in displays makes perovskite LEDs an exciting area of research and development in the semiconductor industry.