Sb/X (X = Mn, Er, Ho) Co-Doped Lead-Free Double Perovskite Cs₂NaInCl₆ for Single-Component White Light Emission

Recently, the incorporation of transition-metal ions into lead-free double perovskite has garnered considerable attention for improving the lattice environment and enhancing photoluminescence (PL) to achieve white light emission. Here, Sb/X (Mn, Er, Ho) co-doped Cs2NaInCl6 (CNIC) microcrystals (MCs) synthesized by conventional hydrothermal method are developed for single-component white light emission with various photoinduced transition mechanisms. Sb doping in CNIC MCs causes the breaking of non-parity forbidden transition under 360 nm laser excitation and results in blue emission; Sb/X co-doping for CNIC MCs successfully broadens the spectrum with multi-peak emission, which consists of unique X-peak emission and blue emission peaked at 445 nm. The energy transfer channels from both free excitons state of CNIC and self-trapping excitons (STEs) state of [SbCl6](3-) to X ion are proved and studied by use of steady-state and time-resolved PL spectroscopy. Among them, Sb/Er co-doped CNIC MCs show unique dual-mode PL under 360 and 980 nm laser excitation. Single-component white light emitting diode is successfully fabricated by adjusting the composition of Sb/X co-doped CNIC MCs, which provides an alternative path for realizing single-component white light illumination.