In Situ Ambient Preparation of Perovskite-Poly(l-lactic acid) Phosphors for Highly Stable and Efficient Hybrid Light-Emitting Diodes

Metal halide perovskite (MHP)-based phosphor-converted light-emitting diodes (pc-LEDs) are limited by the low MHP stability under storage/operation conditions. A few works have recently established the in situ synthesis of MHPs into polymer matrices as an effective strategy to enhance the stability of MHP with a low-cost fabrication. However, this is limited to petrochemical-based polymers. Herein, the first in situ ambient preparation of highly luminescent and stable MHP-biopolymer filters (MAPbBr₃ nanocrystals as an emitter and poly(l-lactic acid) (PLLA) as the matrix) with arbitrary areas (up to ca. 300 cm²) is reported. The MAPbBr₃-PLLA phosphors feature a narrow emission (25 nm) with excellent photoluminescence quantum yields (>85%) and stability under ambient storage, water, and thermal stress. This is corroborated in green pc-LEDs featuring a low-efficiency roll-off, an excellent operational stability of ca. 600 h, and high luminous efficiencies of 65 lm W^-1 that stand out compared to the prior state of the art (e.g., an average lifetime of 200 h at 50 lm W^-1). The filters are further exploited to fabricate white-emitting pc-LEDs with efficiencies of ca. 73 lm W^-1 and x/y CIE color coordinates of 0.33/0.32. Overall, this work establishes a straightforward (one-pot/in situ) and low-cost preparation (ambient/room temperature) of highly efficient and stable MHP-biopolymer phosphors for highly performing and more sustainable lighting devices.