Novel double perovskite Cs2Na0.7Ag0.3InCl6: Mn2+ for deep UV chip-based high color-rendering WLEDs

Novel double perovskite Cs 2 Na 0.7 Ag 0.3 InCl 6 : Mn 2+ material is developed. • Tunable dual emission covering full visible light range is fulfilled. • Novel perovskite material is excited by deep-ultraviolet light. • White LED with high CRI of 87.9 is fabricated by coating double perovskites and commercial BaMgAl 10 O 17 :Eu 2+ blue phosphor on deep-UV chip. The commercial potential of traditional double perovskites in white light-emitting diodes (WLEDs) has been constrained by low photoluminescence quantum yield (PLQY) and narrow emission spectrum, mainly due to parity-forbidden transitions and indirect bandgap characteristics. To address these issues, Ag  +  doped Cs 2 NaInCl 6 (CNIC) are synthesized via solvothermal method. Compared to the undoped sample exhibiting a low PLQY of 2.76%, Ag + doped samples show a high PLQY of 77.56%, attributing to STEs emission of 540 nm. Additionally, a series of Cs 2 Na 0.7 Ag 0.3 InCl 6 : x Mn 2+ novel materials are designed. The results demonstrate that an energy transfer pathway from STEs to Mn 2+ in co-doped system, enabling tunable dual emission across the entire visible spectrum. Notably, Cs 2 Na 0.7 Ag 0.3 InCl 6 : x Mn 2+ materials can be effectively excited by deep-ultraviolet (deep-UV) light. A WLEDs device is fabricated by coating this novel material and commercial BaMgAl 10 O 17 :Eu 2+ blue phosphor on deep-UV chip, producing warm white light with a CIE coordinate of (0.3609, 0.3576), a correlated color temperature (CCT) of 4460 K and a high color rendering index (CRI) of 87.9. These results show that Cs 2 Na 0.7 Ag 0.3 InCl 6 : x Mn 2+ novel materials have potential for application in solid-state lighting.