Delicate Management of Alkaline-Substrate-Induced Interfacial Reactions Enables High-Efficiency and Stable Deep-Red...

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Chemistry

Background:

• All-inorganic CsPbI3 perovskite is promising for deep-red LEDs but suffers from phase transition and defects.
• Alkaline substrate engineering improves perovskite LEDs (PeLEDs), but interfacial reactions are not well understood.

Purpose of the Study:

• To investigate interfacial reactions and develop a stable CsPbI3 perovskite emitter.
• To improve the performance and operational stability of deep-red PeLEDs.

Main Methods:

• Developed a magnesium (Mg)-doped zinc hydroxide (Zn(OH)2) substrate with controlled surface properties.
• Investigated the crystallization and degradation of CsPbI3 films on the modified substrate.
• Analyzed the impact of Mg doping on substrate basicity and interfacial reactions.

Main Results:

• Mg doping reduced oxygen vacancies and surface hydroxyls, decreasing substrate basicity.
• The Mg-doped substrate suppressed organic deprotonation and stabilized CsPbI3 crystallization, reducing defects.
• Interface engineering mitigated degradation under electrical and thermal stress, yielding high-quality emitters.

Conclusions:

• Mg-doped Zn(OH)2 substrates effectively improve CsPbI3 crystallization and stability for PeLEDs.
• This facile interface engineering leads to high-performance deep-red PeLEDs with improved operational lifetime.
• The study provides insights into managing interfacial reactions for advanced perovskite optoelectronics.