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.