Crystal Orientation Drives the Interface Physics at Two/Three-Dimensional Hybrid Perovskites

Area of Science:

• Materials Science
• Solid-State Physics
• Photovoltaics

Background:

• Two-dimensional/three-dimensional (2D/3D) halide perovskites offer enhanced performance in photovoltaics (PVs).
• Understanding the interface physics in 2D/3D perovskite systems is crucial for optimization but remains limited.
• Current optimization strategies for 2D/3D PVs often lack a clear understanding of the structure-property relationship.

Purpose of the Study:

• To elucidate the impact of 2D/3D crystal alignment on interface charge-recombination dynamics in perovskite photovoltaics.
• To investigate how manipulating the 2D layer's orientation influences device performance.
• To provide guidelines for designing advanced multidimensional perovskite interfaces.

Main Methods:

• Utilized time-resolved optoelectronic analysis across femtosecond to microsecond timescales.
• Manipulated 2D crystal growth and orientation via specific fluorination of phenethylammonium (PEA).
• Investigated the role of the 2D layer as an electron barrier and surface passivant.

Main Results:

• Demonstrated a static function of the 2D layer as an electron barrier and homogeneous surface passivant.
• Showcased a dynamic role of the 2D layer in retarding charge recombination.
• Observed a significant enhancement in open-circuit voltage (Voc) attributed to the 2D layer's parallel orientation on the 3D layer.

Conclusions:

• The orientation of the 2D perovskite layer critically influences interface charge dynamics and device performance.
• Specific fluorination of PEA provides a method to control 2D crystal growth and orientation.
• Findings offer precise guidelines for the rational design of multidimensional perovskite interfaces for high-performance PVs.