Ligand Engineering Triggered Efficiency Tunable Emission in Zero-Dimensional Manganese Hybrids for White Light-Emitting Diodes.

Zero-dimensional (0D) hybrid manganese halides have emerged as promising platforms for the white light-emitting diodes ( w -LEDs) owing to their excellent optical properties. Necessary for researching on the structure-activity relationship of photoluminescence (PL), the novel manganese bromides (C ₁₃ H ₁₄ N) ₂ MnBr ₄ and (C ₁₃ H ₂₆ N) ₂ MnBr ₄ are reported by screening two ligands with similar atomic arrangements but various steric configurations. It is found that (C ₁₃ H ₁₄ N) ₂ MnBr ₄ with planar configuration tends to promote a stronger electron-phonon coupling, crystal filed effect and concentration-quenching effect than (C ₁₃ H ₂₆ N) ₂ MnBr ₄ with chair configuration, resulting in the broadband emission (FWHM = 63 nm) to peak at 539 nm with a large Stokes shift (70 nm) and a relatively low photoluminescence quantum yield (PLQY) (46.23%), which makes for the potential application (LED-1, R a = 82.1) in solid-state lighting. In contrast, (C ₁₃ H ₂₆ N) ₂ MnBr ₄ exhibits a narrowband emission (FWHM = 44 nm) which peaked at 515 nm with a small Stokes shift (47 nm) and a high PLQY of 64.60%, and the as-fabricated white LED-2 reaches a wide colour gamut of 107.8% National Television Standards Committee (NTSC), thus highlighting the immeasurable application prospects in solid-state display. This work clarifies the significance of the spatial configuration of organic cations in hybrids perovskites and enriches the design ideas for function-oriented low-dimensional emitters.