Two-dimensional perovskites with alternating cations in the interlayer space for stable light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Lead halide perovskites show promise for photovoltaics but suffer from poor stability.
• Two-dimensional (2D) perovskites offer improved stability over their 3D counterparts.
• Developing stable and high-performance perovskite optoelectronic devices is crucial.

Purpose of the Study:

• To demonstrate high-quality 2D perovskite thin films with alternating interlayer cations.
• To develop efficient and stable near-infrared light-emitting diodes (LEDs) using these novel perovskites.
• To investigate the effect of interlayer spacer cation thickness on device performance and emission.

Main Methods:

• Fabrication of 2D perovskite thin films with alternating cations.
• Fabrication of near-infrared LEDs using the developed perovskite films.
• Characterization of optoelectronic properties, including emission wavelength, external quantum efficiency (EQE), current density (J), radiance, and operational stability.

Main Results:

• High-quality 2D perovskite thin films with alternating interlayer cations were successfully fabricated.
• Efficient near-infrared LEDs with tunable emission from 680 to 770 nm were demonstrated.
• The best-performing device achieved an EQE of 3.4% at 249 mA/cm², maintaining >2.5% EQE up to 720 mA/cm².
• The device exhibited high radiance (77.5 W/Sr m²) and excellent operational stability, retaining ~80% performance after 350 min.

Conclusions:

• Novel alternating interlayer cation 2D perovskites provide highly stable semiconductor thin films.
• These materials are promising for efficient and stable photonic emitters, particularly near-infrared LEDs.
• The tunability of emission by varying interlayer cation thickness opens avenues for customized optoelectronic devices.