Constructing Interfacial Prestress to Achieve Homogeneously Strained Perovskites

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Vertically inhomogeneous strain in perovskite layers hinders efficiency and stability of perovskite solar cells.
• Developing strategies for uniform strain is crucial for advancing perovskite photovoltaic technology.

Purpose of the Study:

• To engineer uniformly strained perovskite films by reducing the surface energy of the TiO2 electron transport layer.
• To enhance the efficiency and operational stability of perovskite solar cells through controlled strain engineering.

Main Methods:

• Hydrothermal synthesis of TiO2 nanocrystals using TiCl4 and integration of ascorbyl glucoside.
• Formation of a liquid/solid/air interface to induce dewetting and trigger a stressed perovskite lattice.
• Precise control over crystallization dynamics at the liquid/solid/air interface.

Main Results:

• Achieved a compressively strained perovskite film with homogeneous out-of-plane strain.
• Improved small-area device efficiency to 25.34% (from 23.20%) and large-area efficiency to 24.13% (from 21.25%).
• Demonstrated remarkable operational stability, retaining over 95% of initial efficiency for over 2000 hours.

Conclusions:

• Integrating ascorbyl glucoside into TiO2 nanocrystals is an effective strategy for strain engineering in perovskite solar cells.
• Uniform strain in perovskite films significantly enhances device performance and long-term stability.
• This mechanically informed approach offers a new paradigm for designing high-performance perovskite photovoltaics.