06096nas a2200217 4500008004100000245005000041210005000091260000800141490000700149520545000156100001805606700001905624700001805643700002005661700002105681700001805702700002305720700003105743700001905774856008505793 2025 eng d00aUltrabroad near infrared emitting perovskites0 aUltrabroad near infrared emitting perovskites cJAN0 v643 a

Phosphor converted light emitting diodes (pc-LEDs) have revolutionized solid-state white lighting by replacing energy-inefficient filament-based incandescent lamps. However, such a pc-LED emitting ultrabroad near-infrared (NIR) radiations still remains a challenge, primarily because of the lack of ultrabroad NIR emitting phosphors. To address this issue, we have prepared 2.5 % W4+-doped and 2.8 % Mo4+-doped Cs2Na0.95Ag0.05BiCl6 perovskites emitting ultrabroad NIR radiation with unprecedented spectral widths of 434 and 468 nm, respectively. Upon band-edge excitation, the soft lattice of the host exhibits broad self-trapped exciton (STE) emission covering NIR-I (700 nm), which then nonradiatively excites the dopants. The mathematical equation –donor ligand Cl reduces the energy of dopant d–d transitions emitting NIR-II with a peak at ~950 nm. Vibronic coupling broadens the dopant emission. The large spin-orbit coupling and local structural distortion might possibly enhance the dopant emission intensity, leading to an overall NIR photoluminescence quantum yield ~40 %. The composite of our ultrabroad NIR phosphors with biodegradable polymer polylactic acid could be processed into free-standing films and 3D printed structures. Large (170mathematical equation 170 mathematical equation ), robust, and thermally stable 3D printed pc-LED panels emit ultrabroad NIR radiation, demonstrating NIR imaging applications.

1 aSaikia, Sajid1 aGopal, Animesh1 aRathod, Radha1 aJoshi, Aprajita1 aPriolkar, K., R.1 aSaha, Surajit1 aSantra, Pralay, K.1 aShanmuganathan, Kadhiravan1 aNag, Angshuman uhttps://library.ncl.res.in/content/ultrabroad-near-infrared-emitting-perovskites