Iron-induced phase engineering for high color-purity blue LEDs in perovskites

Area of Science:

• Materials Science
• Optoelectronics
• Solid State Chemistry

Background:

• Achieving efficient and stable blue emission in perovskite light-emitting diodes (PeLEDs) is challenging due to their wide bandgap.
• Quasi-two-dimensional (quasi-2D) perovskites offer potential for blue PeLEDs, with performance often relying on energy transfer between different 2D phases.

Purpose of the Study:

• To investigate the use of iron additives (FeBr3 and FeCl3) for phase engineering in quasi-2D perovskites.
• To enhance the performance and color purity of blue PeLEDs through controlled phase modulation.

Main Methods:

• Additive-assisted phase engineering using iron halides (FeBr3, FeCl3) in quasi-2D perovskites.
• Photoluminescence spectroscopy to analyze bandgap and FWHM changes.
• Density Functional Theory (DFT) calculations to understand the thermodynamic stabilization of perovskite phases.
• Fabrication and characterization of blue PeLED devices.

Main Results:

• Iron additives effectively suppressed low-n phases and promoted high-n phases in quasi-2D perovskites.
• Bandgap modulation and a significant narrowing of the photoluminescence full width at half maximum (FWHM) were observed.
• DFT calculations confirmed the thermodynamic stabilization of high-n phases by iron additives.
• Blue PeLEDs incorporating FeCl3 showed improved external quantum efficiency (EQE) to 6.01% and luminance to 227.6 cd m-2, compared to pristine devices (3.72%, 177.8 cd m-2).

Conclusions:

• Additive-assisted phase engineering using iron is a viable strategy for developing stable, high-purity blue PeLEDs.
• Controlling the phase distribution in quasi-2D perovskites is crucial for optimizing blue emission properties.
• This approach offers a pathway to overcome limitations in blue emission for next-generation optoelectronic devices.