White Light Emission in Zero-Dimensional Indium Hybrid with Hydrogen Bond

Low-dimensional organic-inorganic metal halides (OIMHs) have been explored as single-component white light emitters for applications in solid-state lighting. Herein, we report a zero-dimensional (0D) In-based OIMH (TMPDA)[InCl₅(H₂O)] (TMPDA = N,N,N',N'-tetramethyl-1,4-phenylenediamine), which crystallizes in the noncentrosymmetric P2₁2₁2₁ space group and contains hydrogen bonds between the adjacent [InCl₅(H₂O)]^2- octahedra in structure. It exhibits a large optical band gap (4.10 eV) and dual-band emission under UV light. Spectroscopic analysis and theoretical calculation indicate that the high (404 nm)- and low (513 nm)-energy emissions are attributed to the bound excitons in organic ligands and self-trapped excitons in [InCl₅(H₂O)]^2- units, respectively. It is found that Sb doping in this 0D hybrid provides additional orange (590 nm) emission assigned to the ³P₁ → ¹S₀ triplet radiative recombination. By adjusting the doping level, the emission color can be turned from turquoise to orange, and interestingly, a single-component white-light emission is realized by balancing the high-energy emission from organic ligand, the turquoise emission from [InCl₅(H₂O)]^2-, and the orange one from [SbCl₅(H₂O)]^2-. This work not only provides a new OIMH showing the single-component white light emission but also demonstrates the potential of In-based hybrids with hydrogen bonds for solid-state luminescence.