Tautomeric mixture coordination enables efficient lead-free perovskite LEDs

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Chemistry

Background:

• Lead halide perovskites offer excellent optoelectronic performance in light-emitting diodes (PeLEDs).
• Concerns regarding lead toxicity necessitate the development of lead-free alternatives.
• Achieving high external quantum efficiencies in lead-free PeLEDs remains a significant challenge.

Purpose of the Study:

• To stabilize lead-free tin perovskites for high-performance PeLEDs.
• To address the challenge of lead removal without compromising device efficiency.
• To explore novel strategies for enhancing the performance of tin-based perovskites.

Main Methods:

• A tautomeric-mixture-coordination strategy was employed using cyanuric acid to stabilize TEA2SnI4 (2-thiopheneethylammonium iodide).
• Incorporation of cyanuric acid induced electron localization and amplified electronic effects on tin atoms.
• Formation of hydrogen-bonded tautomeric dimer and trimer superstructures on the perovskite surface was observed.

Main Results:

• The strategy significantly reduced non-radiative recombination by two orders of magnitude.
• Exciton binding energy was enhanced approximately twofold.
• The developed lead-free tin perovskite PeLED achieved an external quantum efficiency of up to 20.29%.

Conclusions:

• The findings offer insights into stabilizing Sn(II) perovskites through controlled coordination and electron localization.
• The developed material demonstrates performance comparable to state-of-the-art lead-containing PeLEDs.
• This work advances the development of safer, high-performance lead-free perovskite applications.