Tunable dual emission of Ca3Al4ZnO10:Bi3+,Mn4+via energy transfer for indoor plant growth lighting

Abstract

We synthesized a series of Bi³⁺ doped and Bi³⁺ and Mn⁴⁺ co-doped Ca₃Al₄ZnO₁₀ (CAZO) phosphors via a conventional high-temperature solid-state reaction (SSR). Upon excitation at 330 nm, CAZO:Bi³⁺ shows blue-violet emission with a peak located at 405 nm. Under the same excitation source, Bi³⁺ and Mn⁴⁺ co-doped CAZO phosphors show dual emission, where the blue-violet emission is mainly from the ³P₁ → ¹S₀ transition of Bi³⁺ and the far red emission is attributed to the ²E → ⁴A₂ transition of Mn⁴⁺. The intrinsic great overlap between the emission band of Bi³⁺ and the excitation band of Mn⁴⁺ indicates the occurrence of energy transfers from Bi³⁺ to Mn⁴⁺. Fluorescence decays and photoluminescence spectra were measured to investigate the energy transfer process. The energy transfer efficiencies were also calculated. The relative emission intensities of Bi³⁺ and Mn⁴⁺ can be easily controlled by adjusting the concentrations of raw materials. It is demonstrated that the emission of CAZO:Bi³⁺,Mn⁴⁺ matches well with the absorption of four dominating pigments in plants, implying that the as-prepared phosphors are suitable to be applied in agricultural fields.