Dual ligands synergy enables thermal and moisture stability-enhanced blue quasi-2D perovskite for efficient light-emitting diodes

Quasi-2D metal halide perovskite is rising for efficient blue light-emitting diodes due to strong quantum confinement and tunable emission, while a challenge remains in its poor stability of n-phase distribution under external stresses. Herein, the stable blue quasi-2D perovskite under heat and moisture conditions is achieved by dual ligand engineering. The Lewis base moieties − SO₃⁻ from taurine (3S) bind tightly with perovskite edges, inhibiting Ostwald ripening of the perovskite phase caused by the heat, and 3, 3-diphenylpropylamine (DPPA) provides a strong hydrophobicity to the perovskite film, suppressing phase disproportionation induced by the moisture. Accordingly, the blue perovskite film, modified synergistically by the 3S and DPPA dual ligands, maintains its initial photoluminescence quantum yield (PLQY) after over 200 h with 70 °C heating, and only exhibiting a redshift in PL peak wavelength less than 10 nm. Exposing under environment condition of 20 % relative humidity for 300 h, the blue perovskite film still retains its initial PL peak wavelength with PLQY exceeding 50 % of the initial value. This achievement establishes a notable strategy for enhancing both the thermal and moisture stability of blue quasi-2D perovskite. Furthermore, the light-emitting diodes based on the perovskite films display the enhanced operating stability. This work offers an efficient strategy for stabilizing blue quasi-2D perovskite and the corresponding devices for the display application.