Atomically thin two-dimensional hybrid perovskites using hydrophobic superalkali cations with tunable electron...

Area of Science:

• Materials Science
• Solid State Physics
• Computational Chemistry

Background:

• Two-dimensional (2D) metal halide perovskites have tunable direct band gaps.
• However, their electron transition types remain largely unchanged during component engineering.

Purpose of the Study:

• To systematically explore atomically thin (C5NH6)2MX4 hybrid perovskites with hydrophobic superalkali cations.
• To investigate the influence of component engineering on electron transition types and material properties.

Main Methods:

• High-throughput hybrid density functional calculations.
• Ab initio molecular dynamics simulations.

Main Results:

• Electron transition type was converted from M-X to (C5NH6)-X via halide (X) substitution.
• Stable thermodynamic and kinetic properties, sharp valence bands, and tunable direct band gaps were achieved.
• Theoretical power conversion efficiency (PCE) of 32.54% for passivated cubic NH2CHNH2PbI3 (FAPbI3) containing 2D (C5NH6)2PbI4.
• Identified a hybrid Pb-free (C5NH6)2SnI4 perovskite with a 1.56 eV direct bandgap as a potential passivation material.

Conclusions:

• Atomically thin 2D perovskites with superalkali cations exhibit tunable electronic properties and altered electron transitions.
• These materials demonstrate potential for high-efficiency solar cells and device passivation.
• Hydrogen bonding interactions offer further avenues for designing novel organic-inorganic hybrid perovskites.