Zero-Dimensional Lead-Free Halide with Indirect Optical Gap and Enhanced Photoluminescence by Sb Doping

Abstract

Three new lead-free organic–inorganic metal halides (OIMHs) (C7H8N3)3InX6·H2O (X = Cl, Br) and (C7H8N3)2SbBr5 were synthesized. First-principles calculations indicate that the highest occupied molecular orbitals (HOMOs) of the two In-based OIMHs are constituted of π orbitals from [C7H8N3]+ spacers. (C7H8N3)3InX6·H2O (X = Cl, Br) shows an indirect optical gap, which may result from this organic-contributed band edge. Despite the indirect-gap nature with extra phonon process during absorption, the photoluminescence of (C7H8N3)3InBr6·H2O can still be significantly enhanced through Sb doping, with the internal photoluminescence quantum yields (PLQY) increased 10-fold from 5% to 52%. A white light-emitting diode (WLED) was fabricated based on (C7H8N3)3InBr6·H2O:Sb3+, exhibiting a high color-rendering index of 90. Our work provides new systems to deeply understand the principles for organic spacer choice to obtain the 0D metal OIMHs with specific band structure and also the significant enhancement of luminescence performance by chemical doping.

High-efficiency red photoluminescence achieved by antimony doping in organic–inorganic halide (C11H24N2)2[InBr6][InBr4]

“…22 Among these 0D broadband emissive metal halides, Inbased OIMHs have been found to be promising luminescent materials for solid-state lighting. [23][24][25][26][27][28][29][30][31] Chen et al synthesized 0D (C 7 H 10 N) 3 InBr 6 with isolated [InBr 6 ] 3À octahedra in the structure, which shows orange light emission with a relatively high PLQY of B35%. 23 4 ÁCl in which the yellow emission can be largely enhanced with the PLQY being boosted from 20% to 90% via Sb doping.…”

Antimony -doped indium-based halide single crystals enabling white-light emission

“…where In-based hybrids 10,32,41,44 but is obviously smaller than that of Pb-, 27 Sn-, 45 Sb-based 46 hybrids, which is attributed to the strongly antibonding highest occupied molecular orbital due to the existence of s orbital. 47 As shown in Fig.…”

“…The crystal structure of the hybrid was determined to be that of (TMPL) 3 In-based 0D halide hybrids. 11,32,41,44 Single X-ray diffraction crystallographic data of (TMPL) 3 InCl 6 •EtOH are summarized in Table S1, † and selected bond lengths (Å) and bond angles (°) of (TMPL) 3 InCl 6 •EtOH are listed in Tables S2 and S3. † Eqn (1) and ( 2) are used to define the degree of structural distortion of In-Cl bonds and Cl-In-Cl angles in the [InCl 6 ] 3− octahedron:…”

“…Han and co-workers designed 0D A 2 InCl 5 (H 2 O) (A = Rb, Cs) with the photoluminescence quantum yield (PLQY) enhanced from <2% to >80% by doping Sb 3+ ions. 42 44 which showed sharp increase in PLQY due to the incorporation of Sb 3+ ions. While most studies just report enhancement in the quantum yield and luminescence modulation by the introduction of dopant, the exploration of white light emitters is rarely reported.…”

Lead-free broadband orange-emitting zero-dimensional Sb3+-doped indium-based organic–inorganic metal halides

“…Lead-free indium-based metal halide materials have attracted extensive attention in recent years due to their good stability under environmental conditions and excellent photoelectric properties. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]56,59 Moreover, the diversity of organic cations provides favourable conditions for the construction of organic-inorganic hybrid metal halide materials. In existing reports, zero-dimensional (0D) InCl 6 (C 4 H 10 SN) 4 ÁCl:Sb 3+ was produced by doping Sb 3+ into InCl 6 (C 4 H 10 SN) 4 ÁCl, which undergoes a significant enhancement of the emission peak at 550 nm (PLQY 90%).…”