Tunable Dual Emission in Bi³⁺/Te⁴⁺-Doped Cs₂HfCl₆ Double Perovskites for White Light-Emitting Diode Applications

Abstract

Multicolor-emission-based single-phase white light derived from different luminescence centers is an effective way to manipulate the optical properties of halide perovskites. In this work, we developed a codoping strategy to incorporate Bi3+ and Te4+ emission centers into all-inorganic lead-free Cs2HfCl6 perovskite by a hydrothermal method. The as-prepared Bi3+/Te4+-doped Cs2HfCl6 microcrystals show bright blue (Bi3+), yellow (Te4+), and warm-white emissions (Bi3+/Te4+), respectively. The broad efficient dual emission in Bi3+/Te4+ co-doped Cs2HfCl6 is assigned to the typical 3P1 → 1S0 transition emission from Bi3+ originating from [BiHf + VCl] and self-trapped excitons (STEs) from Te4+. Moreover, the concentration-optimized Cs2HfCl6:Te4+ shows excellent antiwater stability and high photoluminescence quantum yield (PLQY) of ∼70%. Meanwhile, a white light-emitting diode (WLED) fabricated using Bi3+/Te4+ co-doped Cs2HfCl6 is close to warm white with a color rendering index (CRI) of 75.4, CIE color coordinate of (0.370, 0.393), and a correlated color temperature (CCT) of 4380 K. These results suggest that Bi3+/Te4+ co-doped all-inorganic lead-free Cs2HfCl6 is a potential single-phase white light-emitting phosphor candidate for solid-state lightings.

Red‐Emitting Perovskite Variant Cs2PtCl6 Phosphor: Material Design, Luminous Mechanism, and Application in High‐Color‐Rendering White Light‐Emitting Diodes

“…[35] The A 2 BX 6 -type phosphor components and single-phase white phosphors have been used to construct white LEDs. [35][36][37][38][39][40] However, the resultant white LEDs, particularly the all-A 2 BX 6 white LEDs, exhibit insufficient color rendering due to the shortage of red light. [41] Therefore, to attain high-color-rendering all-A 2 BX 6 white LEDs, it is an urgent need to develop red-emitting phosphors in the family of A 2 BX 6 perovskite variants.To achieve intrinsic red emissions in the A 2 BX 6 perovskite variants, it is necessary to reduce the bandgaps of the perovskite variants.…”

Lead-free perovskite Rb2Sn1−xTexCl6 with bright luminescence for optical thermometry and tunable white light emitting diodes

“…The expansion of Te–Cl bonds and the strain change of [TeCl 6 ] 2− substitution have important influence factors in the redshift. 31 In order to determine whether the structure of Rb 2 SnCl 6 changes under different Te 4+ substitution contents, the X-ray diffraction (XRD) patterns of Rb 2 Sn 1− x Te x Cl 6 MCs have been exhibited in Fig. 1(c).…”

Self-trapped excitons in soft semiconductors

“…Further development in the doped materials indicates that the properties of STEs can be further tuned by following the co-doping approach. 60,134–137 Due to the different radii and electronic structure of the dopants, co-doping may induce a relatively larger lattice distortion or lead to the formation of a sub-band. 50,60,138–140 Jin et al fabricated a family of lanthanide (Ln 3+ ) ions doped Bi: Cs 2 AgInCl 6 double perovskite structures, which exhibited broadband PL spectra from the visible to the near-infrared range and high PLQY.…”