Substrate Induced p-n Transition for Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Photovoltaics
• Semiconductor Physics

Background:

• The electrical properties (p-type or n-type) of semiconductor materials are crucial for photoelectronic device performance.
• Typically, perovskite films adopt the doping type of the substrate they are deposited on.

Purpose of the Study:

• To develop a novel strategy for inducing a p-type to n-type transition on the perovskite surface.
• To enhance the performance and stability of inverted perovskite solar cells (PSCs) through surface modification.

Main Methods:

• A substrate-induced re-growth technique was employed.
• Initially, a p-type perovskite film was crystallized on a p-type substrate.
• An n-type ITO/SnO2 substrate saturated with perovskite solution was pressed onto the film and annealed to induce secondary re-growth, causing a p- to n-type transition at the surface.

Main Results:

• The secondary re-growth successfully induced a p-type to n-type transition at the perovskite surface.
• This transition created an additional junction, boosting the built-in potential and improving carrier extraction.
• The resulting inverted PSCs achieved over 25% efficiency.

Conclusions:

• The substrate-induced re-growth strategy effectively modifies perovskite surface properties.
• This method significantly enhances the performance and operational stability of inverted PSCs, retaining 90% efficiency after 800 hours of testing.