Fig. 2: Compositional engineering.
From: Focus on perovskite emitters in blue light-emitting diodes
a The representative electronic structure of Pb-X perovskites. σ and σ* denote the bonding and antibonding orbitals, respectively. Eg denotes the bandgap. b Relatively thermodynamic ionization levels of the halide vacancies (VI, VBr, VCl) in MAPbI3, MAPbBr3, and CsPbCl3. c The vapor-assisted (bottom) and vacuum-deposited (top) methods for the fabrication of CsPb(Br,Cl)3 films. d Schematics of the contracted Pb-X octahedral lattices upon B-site substitution, and the enhanced blue-shifted PL emission by a variety of substitution candidates. e Energy diagram of the Mn-doped perovskite (top), and the PL picture of CsMnyPb1-yBrxCl3-x with different doping content of Mn2+ (bottom). f The distribution and corresponding energy diagram of the Y-doped CsPb(Br,Cl)3 grain. g Normalized electroluminescence (EL) spectra of the blue PeLED devices under 6 V bias with the increment of EABr (top). The energy diagram of the CsPbBr3 with and without 60% EA+ substitution and the schematic of octahedral distortion (bottom). e is reprinted from ref. 35 with permission from Elsevier
