Wavelength-Tuneable Near-Infrared Luminescence in Mixed Tin–Lead Halide Perovskites

Abstract

Near-infrared light-emitting diodes (NIR-LEDs) are widely used in various applications such as night-vision devices, optical communication, biological imaging and optical diagnosis. The current solution-processed high-efficiency perovskite NIR-LEDs are typically based on CsPbI3 and FAPbI3 with emission peaks being limited in the range of 700–800 nm. NIR-LEDs with longer emission wavelengths near to 900 nm can be prepared by replacing Pb with Sn. However, Sn-based perovskite LEDs usually exhibit a low efficiency owing to the high concentration of Sn-related defects and the rapid oxidation of Sn2+ to Sn4+, which further induces the device degradation. These problems can be solved by rationally adjusting the ratio between Pb content with Sn. Mixed Sn-Pb halide perovskites with a smaller bandgap and superior stability than pure Sn-based perovskites are promising candidates for manufacturing next-generation NIR emitters. In this study, we systematically investigated the optical properties of a family of hybrid Sn and Pb iodide compounds. The emission spectra of the mixed Sn-Pb halide perovskites were tuned by changing the Sn:Pb ratio. Consequently, the peak emission wavelength red-shifted from 710 nm to longer than 950 nm. The absorption and photoluminescence emission properties associated with different compositions were compared, and the results demonstrated the potential of MA- and FA-based mixed Sn-Pb halide perovskites for preparing low-cost and efficient NIR-LEDs. In addition, we clarified the influence of cations on the bandgap bowing effect and electronic properties of mixed Sn-Pb halide perovskites.

Near‐infrared emitting metal halide materials: Luminescence design and applications

“…239 In addition, mixed Sn-Pb halide perovskites by partly replacing Pb 2+ with Sn 2+ were proposed to address the toxicity of pure lead-based halide perovskites and poor stability of pure Sn-based halide perovskites. 112 The mixed Sn-Pb halide perovskites with adjusted bandgap, absorption, and PL properties are promising candidates for fabricating low-cost and efficient NIR LEDs. Du et al 220 conducted the cation substitution of Sb 3+ for Bi 3+ to regulate the optoelectronic properties of Cs 2 AgBiBr 6 .…”

“…Sn 2+ substituting Pb 2+ can further decreases the bandgap, realizing longerwavelength NIR emission in MASnI 3 . 95,112 Hence, the substitution of chemical composition has a significant effect on the bandgap tuning of lead halide perovskites.…”

Turning Self‐Trapped Exciton Emission to Near‐Infrared Region in Thermochromism Zero‐Dimensional Hybrid Metal Halides

“…[ 6 ] There are only few reports about low dimensional metal halides with NIR STE luminescence. Among these reports, there are three strategies have been used: I) introducing bivalent Sn 2+ as metal site for perovskite structure; [ 7 ] II) incorporating rare earth elements; [ 8 ] and III) doping other metal ions (e.g., Cr 3+ ions). [ 9 ] However limited progress has been made due to Sn 2+ is unstable and easily to be oxidized.…”