荧光粉
掺杂剂
材料科学
光电子学
发光二极管
光致发光
近红外光谱
有机发光二极管
兴奋剂
白炽灯
发光
二极管
红外线的
光学
纳米技术
物理
图层(电子)
作者
Sajid Saikia,Ashwini Gopal,Radha Rathod,Aprajita Joshi,K. R. Priolkar,Surajit Saha,Pralay K. Santra,Kadhiravan Shanmuganathan,Angshuman Nag
标识
DOI:10.1002/anie.202415003
摘要
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 (680 nm), which then nonradiatively excites the dopants. The π‐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 (170 × 170 mm2), robust, and thermally stable 3D printed pc‐LED panels emit ultrabroad NIR radiation, demonstrating NIR imaging applications.
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