Antimony-Doping Induced Highly Efficient Warm-White Emission in Indium-Based Zero-Dimensional Perovskites

Abstract

Indium (In)-based halide perovskites are desirable for next-generation phosphors and emitting devices, due to their broad emission, nontoxicity, and oxidization avoidance capabilities. However, the In-based perovskites always exhibit low external photoluminescence quantum efficiency (PLQE) as a result of their weak light absorption near the corresponding excitation region, and thus, are limited in extended applications. Herein, we have developed an antimony (Sb)-doping strategy to improve the absorption ability of Cs 2 InCl 5 •H 2 O in the ultraviolet region. Excitingly, we obtained a warm-light phosphor with ultrahigh external (internal) PLQE of 72.8% (86.7%). Typically, upon 1.5% Sb doping, the single-crystalline Cs 2 InCl 5 •H 2 O perovskite displayed a stronger warm-light emission at ∼ 610 nm with a large Stokes shift of 295 nm and full width at half maximum (FWHM) of 164 nm. Density functional theory (DFT) calculations revealed that the Sb-doping induced an impurity level in the bandgap, increasing the density of state (DOS), and promoted more carriers into the conduction band maximum. Furthermore, external PLQE from 18% to 59% could be realized in other zero-dimensional In-based perovskites through the same doping strategy.

Photoluminescence of Singlet/Triplet Self‐Trapped Excitons in Sb3+‐Based Metal Halides

“…Similar phenomenon can also be observed in Cs 2 InCl 5 ·H 2 O:Sb 3+ . [ 15c,44 ] Both compounds exhibit a large Stokes shift of the dominant triplet emission and the optical properties can be explained based on the energy levels of ns 2 free ion. The yellow emission bands were attributed to the strong electron–phonon coupling (large S factor of 32.28) for Cs 2 InCl 5 ·H 2 O:Sb 3+ .…”

“…[ 1a,b,5e,11d,45 ] Along a similar line, halogen substitution from Cl − to Br − and I − anion also lead to a redshift in both PL and PLE spectra in Cs 2 InCl 5 ·H 2 O:Sb 3+ compounds. [ 15c,44 ] In addition, the influence of A‐site cations and water molecules on optical properties is also significant. [ 35b,44,46 ] The A‐site cations affected the PL emission slightly because the STEs luminescence is mainly related to inorganic polyhedron.…”

“…[ 15c,44 ] In addition, the influence of A‐site cations and water molecules on optical properties is also significant. [ 35b,44,46 ] The A‐site cations affected the PL emission slightly because the STEs luminescence is mainly related to inorganic polyhedron. In contrast, water molecules have an intense influence on optical properties.…”

Multiple Hydrogen Bond-Induced Structural Distortion for Broadband White-Light Emission in Two-Dimensional Perovskites

“…As shown in Figure 3c, the lifetime of the broad STE emission at ∼580 nm became increasingly longer as the temperature decreased from 300 to 100 K. The lengthening of the broadband emission lifetime can be ascribed to the thermal equilibrium between the FEs and STEs that govern the thermally activated trapping of FEs in the STE state. 12,36…”

“…Organic−inorganic hybrid-halide perovskites (OIHPs) have attracted a great deal of attention for their excellent optical-electric properties, such as a high absorption coefficient, a high charge-carrier mobility, and a long carrier recombination lifetime, making OIHPs excellent candidates in many important areas, including solar cells, [1][2][3][4] light-emitting diodes, [5][6][7][8] lasers, 9 solid-state lighting, 10 and scintillators [11][12][13] for radiation detection. Lately, organic-inorganic lead-halide perovskites have been found to be a promising class of scintillator materials for X-ray imaging, with the ability to convert high-energy X-ray photons into low-energy visible photons.…”