Bifacial passivation towards efficient FAPbBr₃-based inverted perovskite light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Chemistry

Background:

• Perovskite light-emitting diodes (PeLEDs) offer promising optoelectronic properties but suffer from efficiency and stability issues.
• Surface defects and non-radiative recombination in perovskite films limit device performance.
• Existing inorganic electron transporting layers (ETLs) have inherent disadvantages that hinder optimal device function.

Purpose of the Study:

• To develop a unique passivation technique for both bottom and top surfaces of perovskite layers.
• To enhance the efficiency and stability of inverted perovskite light-emitting diodes (PeLEDs).
• To overcome the limitations of traditional inorganic ETLs in PeLED fabrication.

Main Methods:

• Fabrication of an organic/inorganic hybrid ETL, ZPM (ZnO-in-polymer matrix), comprising ZnO nanoparticles in polyvinylpyrrolidone.
• Surface modification using PEABr solution to create a FAPbBr₃/PEA₂PbBr₄ 3D/2D hybrid structure.
• Passivation of both bottom and top sides of the perovskite layer to minimize defects and improve film quality.

Main Results:

• The ZPM ETL passivated surface defects and improved the morphology and stability of the FAPbBr₃ film.
• The 3D/2D hybrid structure and hybrid ETL synergistically reduced grain size, facilitating radiative recombination.
• Non-radiative recombination was suppressed at interfaces and within the perovskite layer, leading to record device performance.

Conclusions:

• The developed passivation strategy significantly enhances the performance of FAPbBr₃-based inverted PeLEDs.
• The combination of hybrid ETL and surface modification is crucial for achieving high efficiency and stability.
• This work sets a new benchmark for green PeLEDs, paving the way for future optoelectronic applications.