Polyaniline-Enabled Defect Passivation for Stable and Efficient MAPbI₃-Based Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Methylammonium lead iodide (MAPI) perovskite solar cells face challenges from defect-induced nonradiative recombination and poor operational stability.
• Effective strategies are needed to improve film quality, charge-carrier dynamics, and device longevity.

Purpose of the Study:

• To investigate polyaniline (PANI) as a multifunctional additive for enhancing MAPI perovskite solar cells.
• To assess PANI's impact on film quality, charge-carrier dynamics, device performance, and stability.

Main Methods:

• Incorporation of polyaniline (emeraldine base form) into MAPI perovskite films.
• Characterization using X-ray photoelectron spectroscopy (XPS) for defect analysis.
• Photoluminescence (PL) and time-resolved photoluminescence (TRPL) for charge-carrier dynamics.
• Device performance testing (PCE, Voc) and stability assessments (thermal, photostability).

Main Results:

• PANI enhanced MAPI crystallinity and grain size without altering the bandgap.
• XPS revealed PANI's Lewis acid-base coordination passivated Pb2+ defects.
• PANI-modified films showed increased optical absorption, PL intensity, and carrier lifetimes (813.4 to 971.6 ns).
• Optimized devices achieved 11.55% PCE and 1.04 V Voc, up from 9.41% and 0.95 V for pristine MAPI.
• PANI-modified cells demonstrated excellent thermal and photostability.

Conclusions:

• Polyaniline is an effective additive for simultaneously improving MAPI perovskite film quality, charge-carrier dynamics, and device performance.
• PANI significantly enhances the operational stability and durability of perovskite solar cells.
• This work presents a scalable strategy for developing efficient and stable perovskite solar cells using PANI.