Triple Synergistic Stabilization in Zn: CsPbBr_xI_3-x-PVDF for High-Efficiency Pure Red Emission Films

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Mixed halide perovskite CsPbBr_xI_3-x nanocrystal (NC) films are promising for pure red perovskite light-emitting diodes (PeLEDs).
• However, pure red perovskites suffer from environmental instability, defects, and spectral instability during halide ion exchange.

Purpose of the Study:

• To develop a stable pure red light-emitting Zn: CsPbBr_xI_3-x-PVDF film using a swelling method.
• To improve the crystal structure, anion exchange control, and defect passivation of red perovskite films.

Main Methods:

• A swelling method involving post-treatment with CsBr-ZnI₂ at room temperature was employed.
• The PVDF-CsBr-ZnI₂ system was utilized for synergistic effects in anion exchange, crystal stabilization, and defect passivation.
• The photoluminescence emission of Zn: CsPbBr_xI_3-x-PVDF films was tuned and characterized.

Main Results:

• Stable pure red light emission was achieved with tunable photoluminescence from 665 to 580 nm.
• The 637 nm emitting films exhibited a narrow full width at half-maximum (fwhm) of 50 nm and a high photoluminescence quantum yield (PLQY) over 47.27%.
• The films served as conversion layers for stable pure red LEDs meeting CIE Rec. 2020 standards with sustained electrical stability.

Conclusions:

• The developed swelling method with PVDF-CsBr-ZnI₂ offers a novel strategy for high-quality perovskite lighting flexible thin films.
• The combination of halide exchange, Zn passivation, and polymer encapsulation significantly enhances the stability and performance of red perovskite films.
• This approach paves the way for advanced perovskite-based optoelectronic devices, particularly in pure red LEDs.