A Multifunctional LiF as Passivated Material for an Efficient and Stable Perovskite Photodetector

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Defects in metal cation and halide anion sites of perovskite films critically impact photodetector performance and stability.
• Passivation strategies are essential for mitigating these defects and improving device characteristics.

Purpose of the Study:

• To investigate the use of lithium fluoride (LiF) as a passivation material for perovskite films.
• To enhance the performance and stability of perovskite photodetectors through LiF passivation.

Main Methods:

• LiF was incorporated into the perovskite bulk and applied as a surface passivation layer.
• Characterization of LiF-perovskite interactions, including hydrogen bonding and ionic interactions.
• Evaluation of photodetector performance metrics such as external quantum efficiency (EQE) and detectivity.
• Stability testing under continuous operation.

Main Results:

• LiF effectively passivated both lattice and surface defects in MAPbI_3-xBr_x perovskite films.
• LiF passivation suppressed recombination, leading to enhanced carrier mobility and device stability.
• The optimized LiF-passivated photodetector achieved a high EQE of 87.5% and detectivity of 4.48 × 10¹³ Jones.
• The device demonstrated remarkable stability, retaining 82% of its EQE after 2400 hours of operation.

Conclusions:

• LiF is a highly effective passivation material for perovskite photodetectors.
• LiF passivation significantly improves device performance, carrier dynamics, and long-term operational stability.
• This approach offers a promising route for developing robust and high-performance perovskite-based optoelectronic devices.