Color-pure red light-emitting diodes based on two-dimensional lead-free perovskites

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Developing efficient red light-emitting diodes (LEDs) with precise color coordinates is crucial for advanced display technologies like wide color gamut displays.
• Existing red emitters often contain heavy metals like cadmium (Cd) or lead (Pb), posing environmental and health concerns.

Purpose of the Study:

• To engineer high-efficiency, lead-free perovskite LEDs (PeLEDs) that satisfy the demanding color coordinate specifications for red emitters in Rec. 2100.
• To investigate the role of valeric acid (VA) in improving perovskite film quality and device performance.

Main Methods:

• Synthesized lead-free (PEA)2SnI4 perovskite materials for LEDs.
• Utilized valeric acid (VA) during perovskite crystallization to control morphology and prevent tin oxidation.
• Fabricated and characterized PeLED devices, measuring external quantum efficiency (EQE) and operational stability.

Main Results:

• Achieved red PeLEDs with color coordinates (0.708, 0.292), meeting the Rec. 2100 standard.
• Demonstrated an external quantum efficiency (EQE) of 5% for the PeLEDs.
• Observed an operating half-life exceeding 15 hours at an initial brightness of 20 cd/m².
• Showcased improved film morphology and reduced Sn⁴⁺ content due to VA incorporation.

Conclusions:

• Valeric acid effectively controls perovskite crystallization, enhancing film morphology and device stability.
• The developed lead-free PeLEDs show significant potential for next-generation display technologies.
• This work highlights a viable pathway towards environmentally friendly and high-performance optoelectronic devices.