we have demonstrated the capability of reconfiguring the distribution of strain in a lead-free perovskite, CsSnI₃. Through a combinative evaporation technique, an ideal condition could be reached such that the strain at the top and bottom interfaces of the perovskite sample was minimized (from −0.26% to −0.02%). The tendency of the oxidation of Sn²⁺ towards higher chemical states was suppressed. The additional degree of freedom for strain reconfiguration enabled the demonstration of ultra-stable lead-free PeLEDs with ultralong T₅₀ lifetimes of 1,250 h and 3,350 h under intense currents of 100 mA cm⁻² and 25 mA cm⁻², respectively. Our lead-free devices represent the most stable PeLEDs under a wide range of current densities (25–800 mA cm⁻²). The device lifetime (at 100 mA cm⁻²) outperforms the most stable lead-based PeLEDs by ~5 times and lead-free PeLEDs by ~31 times, and is superior to those of the state-of-the-art organic and quantum-dot LEDs . Our work addresses the long-standing trade-off between eco-friendliness and stability in perovskite devices, paving the way towards real-world applications.

This research was jointly conducted by Professor Di Dawei from Zhejiang University, along with researcher Zhao Baodan and their team, in collaboration with research institutions from Xi'an Jiaotong University, etc. It was published online in the top international academic journal "Nature Photonics" on April 27, 2026.

Link: https://www.nature.com/articles/s41566-026-01901-7