Bidentate Ligand Engineering of Red Perovskites for Efficient Exciton Transfer and Lattice Rigidity
Zhen-Li Yan, Ching-Wei Yang, Yu-Xuan Huang, Chien-Hsin Wu, Ying-Chi Huang, Bi-Hsuan Lin, Jean-Sebastien Benas, Ja-Hon Lin, Ru-Jong Jeng, Chihaya Adachi, Chi-Ching KuoAbstract
Bidentate ligand engineering provides a versatile strategy to regulate crystallization and lattice dynamics in metal halide perovskites. Herein, a bidentate malonamide ligand, butyl-malonamide-phenylene (Bi-BMP), is incorporated into red 2D/quasi-2D/3D perovskites (PVSK) to construct efficient exciton-funneling channels and enhance crystal rigidity. The malonamide groups form strong dipole–ion coordination with Pb2+, promoting uniform phase growth and balanced dimensional distribution, while the rigid phenylene backbone suppresses thermal lattice expansion and field-induced distortion. These dual functions yield reduced exciton–phonon coupling (γLO = 130 meV) and suppressed nonradiative recombination, resulting in a sixfold enhancement of solid-film PLQY (26.9%). Consequently, Bi-BMP@PVSK devices achieve an EQE of ≈14%, a tenfold longer operational lifetime, and color-pure red emission (CIE 0.623, 0.260) approaching the Rec. 2020 standard. This dual-functional molecular design establishes a general strategy for highly efficient and durable red PeLEDs.