Zero-dimensional antimony(III)-doped indium(III) chloride hybrids with unusual green self-trapped exciton emission by significant angular deformation of the expanded metal octahedron

Lead-free indium(III) chlorides hybrids incoporated with 1-ammonium-4-methylpiperazinium and well-tunable Sb(III)-doping concentrations are hydrothermally prepared. • The perfectly regular [MCl6] 3− octahedra and axially compressed [MCl6] 3− octahedra are discretely embedded in a cationic matrix of 1-ammonium-4-methylpiperazinium and hydronium ion, resulting in zero-dimensional structure. • The optimized sample with Sb(III)-doping level of 3.44% exhibits unusual green triplet self-trapped exciton emission centered at 505 nm with high photoluminescence quantum yield of near-unity. Crystalline organic-inorganic metal halides (OIMHs) with environmental friendliness, high stability and soft crystal lattice have been emerging as next-generation high-performance luminescence materials for optoelectronic devices. To well-balance structural stability and photoluminescence enhancement, a series of zero-dimensional (0D) lead-free indium(III) chloride hybrids with well-tunable Sb(III)-doping concentrations have been hydrothermally prepared. In these materials, perfectly regular and axially compressed [MCl 6 ] 3− octahedra are discretely embedded in a matrix composed of 1-ammonium-4-methylpiperazinium and hydronium ion. It is the first time that organic cations and hydronium ions synergistically modulate the structural distortion of metal polyhedra embedded in a 0D host matrix. The optimized doped crystal of (C 5 H 15 N 3 ·2H 3 O) 3 In 2 Cl 18 ⋅0.25H 2 O:3.44%Sb with excellent structural and photophysical stability exhibits a bright broadband green triplet self-trapped exciton ( 3 STE) emission centered at 505 nm with a full width at half-maximum of 113 nm, a high photoluminescence quantum yield of near-unity and long-lived lifetime up to 88.3 μs. Systematical structural comparisons and spectral measurements demonstrate that the scarcely observed high-energy 3 STE emission is determined by the expanded [SbCl 6 ] 3− octahedron with significant angular deformation. Thus, the well-tuned green STE emission achieved via the self-designed doping scheme represents meaningful research progress, establishing an effective host-design guideline to steer STE emission toward green region. 0D Sb(III)-doped indium(III) chloride hybrids with regular and axially shortened octahedra alternately embedded in 1-ammonium-4-methylpiperazinium matrix exhibit unusual green 3 STE emission centered at 505 nm by preferred angular deformation of the expanded [SbCl 6 ] 3− octahedra. Download: Download high-res image (314KB) Download: Download full-size image