New Material Extends Infrared Detection to Wavelengths Currently Out of Reach
Researchers have engineered a lead-free crystal material that detects near-infrared light at 1300 nanometers—a significant leap beyond what existing alternatives can achieve. The breakthrough opens possibilities for thermal imaging, medical diagnostics, and autonomous systems that need to see beyond visible light.
Originaltitel: Palladium-Doped Cs<sub>2</sub>AgBiBr<sub>6</sub> with 1300 nm Near-Infrared Photoresponse
<p>Lead-free halide double perovskite (HDP) Cs<sub>2</sub>AgBiBr<sub>6</sub> has set a benchmark for research in HDP photoelectric applications due to its attractive optoelectronic properties. However, its narrow absorption range is a key limitation of this material. Herein, a novel dopant, palladium (Pd), is doped into Cs<sub>2</sub>AgBiBr<sub>6</sub> and significantly extends the absorption to ≈1400 nm. Pd<sup>2+</sup> ions are partially doped in the host lattice, most probably replacing Ag atoms and introducing a sub-bandgap state within the host bandgap, as indicated by the combination of spectroscopical measurements and theoretical calculations. Importantly, this sub-bandgap state extends the photoresponse of Cs<sub>2</sub>AgBiBr<sub>6</sub> up to the NIR-II region of 1300 nm, setting a new record for HDPs. This work demonstrates a novel and efficient dopant for HDPs and highlights the effectiveness of employing a sub-bandgap to broaden the absorption of HDPs, shedding new light on tailoring large bandgap HDPs for NIR optoelectronic applications.</p>