Additive Screening for Suppressing Light-Induced Phase Segregation and Ionic Activity in Halide Perovskite Devices

Area of Science:

• Materials Science
• Solid-State Chemistry
• Device Physics

Background:

• Mixed halide perovskites are susceptible to halide segregation under illumination, driven by ion migration.
• This instability limits the operational lifetime and performance of perovskite-based devices.
• Additive engineering is a key strategy to mitigate ion migration and enhance stability.

Purpose of the Study:

• To investigate the efficacy of various additives in suppressing halide segregation in MAPb(Br_xI_1-x)₃.
• To understand the influence of different additive chemistries on ionic migration across a compositional gradient.
• To correlate additive-induced stability with performance in switchable photovoltaic and memristor devices.

Main Methods:

• A high-throughput platform was employed to screen five additives: KI, RbBr, Rb₂CO₃, TBABF₄, and GAI.
• The additives' impact on phase segregation across the MAPb(Br_xI_1-x)₃ compositional gradient was analyzed.
• Lateral memristors were fabricated to evaluate device performance and ionic migration tendencies.

Main Results:

• Certain additives, like tetrafluoroborate and KI, showed selective reduction in ionic migration.
• Rubidium-based additives and guanidinium iodide (GAI) consistently suppressed ionic migration across the compositional gradient.
• GAI-added memristors exhibited significantly reduced hysteresis (HI = 0.036) compared to KI-added devices (HI = 0.64), indicating suppressed ionic migration.

Conclusions:

• Additive selection is crucial for controlling ionic migration and phase stability in mixed halide perovskites.
• GAI and rubidium-based additives are effective in suppressing ionic migration, leading to improved device characteristics.
• This high-throughput screening approach provides a valuable framework for optimizing perovskite optoelectronic devices, including solar cells and LEDs.