Fig. 1.

Structural and optical properties of (NEA)₂MnBr₄. a Crystalline structure of (NEA)₂MnBr₄. b Full PL spectrum of (NEA)₂MnBr₄ and corresponding optical photo of drop-casted (NEA)₂MnBr₄ film. The blue emission region of (NEA)₂MnBr₄ and NEABr is in the inserted figure. c Fourier transform infrared (FTIR) spectrum of (NEA)₂MnBr₄ film and precursor NEABr film. d Resulting color changes of samples by heating and cooling sample. e XRD patterns of (NEA)₂MnBr₄ under wet and dry environment. f PL spectra under vacuum conditions by varying the temperature. g PL spectra of (NEA)₂MnBr₄ film under different temperatures