Enhanced Structural Stability and Photo Responsiveness of CH3NH3SnI3 Perovskite via Pressure-Induced Amorphization and Recrystallization (1612.01649v1)

Abstract: An organic-inorganic halide perovskite of CH3NH3SnI3 with significantly improved structural stability is obtained via pressure-induced amorphization and recrystallization. In situ high-pressure resistance measurements reveal an increased electrical conductivity by 300% in the pressure-treated perovskite. Photocurrent measurements also reveal a substantial enhancement in visible-light responsiveness. The mechanism underlying the enhanced properties is demonstrated to be associated with the improved structural stability.

Enhanced Structural Stability and Photo Responsiveness of CH NH SnI3 Perovskite via Pressure-Induced Amorphization and Recrystallization

The paper focuses on a comparative evaluation of the structural stability, electrical conductivity, and photoresponsive behavior of the lead-free organotin halide perovskite, CH$_3$NH$_3$SnI$_3$ (MASnI$_3$), in both pre and post high-pressure treatment phases. The primary objective is to address the prevailing stability issues that compromise the photovoltaic efficiency of perovskite solar cells (PSCs) while simultaneously reducing reliance on toxic lead components.

Key Experimental Findings

1. Structural Phase Transition:
   • MASnI$_3$ undergoes a crystallographic phase transition from tetragonal P4mm symmetry to orthorhombic Pnma symmetry at approximately 0.7 GPa, followed by amorphization beyond 3 GPa.
2. Recrystallization and Stability Improvement:
   • Upon decompression, the amorphous phase recrystallizes into the perovskite structure, maintaining its form even up to 30 GPa during subsequent recompression, thereby evidencing a significant enhancement in structural stability.
3. Enhanced Electrical Conductivity:
   • Post-pressure treatment, a remarkable three-fold increase in MASnI$_3$ conductivity was observed, attributed to enhanced carrier mobility arising from improved cubic symmetry and reduced unit cell volume.
4. Increased Photo Responsiveness:
   • Photocurrent measurements under pressure indicate notable improvements in light responsiveness, correlating with increased electron mobility from pressure-induced structural refinements.

Theoretical and Practical Implications

This research advances the understanding of the pressure-induced structural dynamics of hybrid perovskites and their impact on electronic and optoelectronic properties. The transformation and enhanced cubic symmetry achieved through pressure treatments facilitate greater orbital overlap and reduced carrier effective masses, promoting high mobility conducive to efficient electron transport. The improved photovoltaic properties of pressure-treated MASnI$_3$ exemplify the potential for developing high-performance, lead-free solar cells, mitigating environmental concerns associated with lead toxicity.

Future Directions in AI and Perovskite Research

Further exploration into pressure-induced phenomena can inform strategies to optimize the performance of hybrid perovskite materials. Computational simulations coupled with experimental insights could reveal novel approaches for strain-induced modifications of electronic properties, broadening the scope high-pressure applications in clean energy technologies. AI-driven data analyses and modeling could streamline the identification and optimization of material compositions and structural parameters, catalyzing advances in prototyping efficient, sustainable photovoltaic devices.

In summary, the paper demonstrates the utility of high-pressure techniques for enhancing the structural and functional attributes of lead-free organotin perovskites, presenting a promising paradigm for future development in photovoltaic materials research.