Antimony-Triggered Tunable White Light Emission in Lead-Free Zero-Dimensional Indium Halide with Ultrastable CCT of White Light Emitting Diodes

Abstract

A highly efficient and easily tunable luminescence is significant for solid-state luminescent (SSL) materials. However, achieving a photoluminescence quantum yield (PLQY) close to unity and tuning the emission remain challenging tasks. Metal doping strategies enable resolution of these issues. Herein, we report the preparation of a novel organic−inorganic lead-free indium-based metal halide hybrid (MP) 3 InCl 6 •EtOH (MP = C 4 H 10 ON) with a typical zero-dimension structure. When excited at 320 nm, (MP) 3 InCl 6 •EtOH exhibits a dual emission band at 420 and 600 nm, which originates from the organic cation [MP] and the [InCl 6 ] 3− octahedral unit. The photoluminescence can be significantly enhanced through Sb 3+ doping, resulting in an increase in PLQY from 0.78% to near unity. Multiple emission color tunings have been achieved by regulating the Sb doping level and the radiation wavelength, resulting in a change in emission color from blue → white → orange. Optical characterizations reveal that the significantly enhanced emission centered at 600 nm can be attributed to more efficient absorption, closely associated with an additional 1 S 0 → 3 P 1 transition in the inorganic octahedron [In(Sb)Cl 6 ] 3− due to Sb 3+ doping. With its excellent optical performance, a white light emitting diode (WLED) has been successfully fabricated by coating the mixture of (MP) 3 InCl 6 •EtOH:15%Sb 3+ with blue phosphor BaMgAl 10 O 17 :Eu 2+ onto a UV LED chip. The WLED device exhibits perfect white light emission with regard to the International Commission on Illumination (CIE) coordinates of (0.36, 0.34). Significantly, the WLED device maintains a stable correlated color temperature (CCT) range of 4119−4393 K and CIE coordinates (x: 0.37− 0.34, y: 0.35−0.33) as the driven current varies from 20 to 200 mA, demonstrating outstanding stability across different power levels. This work not only presents a novel system for achieving remarkably enhanced luminescent performance and tuning emission bands in 0D metal halides but also represents a significant step toward achieving resistance to color drifting for stable WLEDs.

A ligand-incorporating strategy towards single-component white light in ionic zero-dimensional indium chlorides

“…The In–Cl bond lengths range from 2.4349(6) Å to 2.5095(6) Å, which are comparable to those of previously reported compounds. 36–38 The In–N bond lengths range from 2.3026(19) Å to 2.3078(17) Å, slightly longer than those of [In(bipy)(H 2 O)Cl 3 ]·CH 3 CN. 39 As shown in Fig.…”

Halogen Content Tunes the Color Temperature of White Light and Afterglow in Zero-Dimensional Hybrid Indium Halides

“…The conventional approach to boost the emission efficiency of 0D In-based OIMHs is Sb 3+ doping. Utilizing the complementarity effect between the cyan/blue emission of the In center or the organic component and the red/yellow ones from the STEs of the Sb 3+ center, the white-light emission can be obtained in some 0D In-based OIMHs by subtly adjusting the Sb 3+ doping level. − For these 0D Sb 3+ -doped indium OIMHs emitting white light, the required Sb 3+ doping amount is often in trace amounts (0.004–1%). Once the amount of Sb 3+ is overabundant, the resultant bulk materials tend to emit nearly fixed spectral ranges (yellow to red light) resulted by the STEs of Sb 3+ -centered polyhedra, ,− for the negligible potential energy barrier between FEs and STEs is in favor of the low-energy STE emission, but will severely suppress the high-energy FE emission.…”