Stable High-Performance Flexible Photodetector Based on Upconversion Nanoparticles/Perovskite Microarrays Composite.

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Methylammonium lead halide perovskite (MAPbI3) offers high-performance semiconductor properties for optoelectronics.
• Current perovskite photodetectors are limited by UV-visible photoresponse and poor environmental stability.

Purpose of the Study:

• To develop a flexible planar photodetector with enhanced performance and stability.
• To investigate the integration of MAPbI3 with NaYF4:Yb/Er upconversion nanoparticles (UCns).

Main Methods:

• Fabrication of a flexible photodetector using MAPbI3 microarrays and UCns.
• Characterization of photodetection capabilities in visible and near-infrared (NIR) regions.
• Assessment of environmental stability under humid conditions.

Main Results:

• Achieved high detectivity (D*) of 5.9 × 10^12 Jones in the visible spectrum.
• Demonstrated excellent NIR photoresponse at 980 nm with responsivity (R) of 0.27 A W^-1 and D* of 0.76 × 10^12 Jones.
• Enhanced long-term stability, retaining 70% performance after 1000 h in 30-40% RH humidity compared to 27% for neat MAPbI3.

Conclusions:

• The composite of perovskite and UCns significantly enhances photon absorption and carrier lifetime.
• The hydrophobic UCns layer acts as a moisture barrier, improving device stability.
• This composite material is promising for high-performance, stable broadband optoelectronic devices.