Synchronous Interface Modification and Bulk Passivation via a One-Step Cesium Bromide Diffusion Process for Highly...

Area of Science:

• Materials Science
• Photovoltaics
• Nanotechnology

Background:

• Perovskite solar cells (PSCs) require effective film modification for improved performance.
• Modification strategies must consider the asymmetric structure and charge dynamics of perovskites.
• Existing methods may not optimally address both interface and bulk properties simultaneously.

Purpose of the Study:

• To develop a one-step method for simultaneous interface modification and bulk passivation in PSCs.
• To enhance the performance of perovskite solar cells by leveraging the asymmetric structure.
• To investigate the impact of cesium bromide diffusion on perovskite film properties and device efficiency.

Main Methods:

• A one-step diffusion process using cesium bromide (CsBr) was employed for perovskite film modification.
• The CsBr diffusion was designed to create synchronous interface modification and bulk asymmetric passivation.
• Characterization of perovskite crystallization, band alignment, and charge recombination was performed.

Main Results:

• Power conversion efficiency (PCE) of PSCs was significantly boosted from 19.5% to 22.1%.
• CsBr diffusion improved perovskite crystallization and enhanced charge extraction through better band alignment.
• A gradient distribution of CsBr in the perovskite bulk effectively suppressed charge recombination.

Conclusions:

• One-step CsBr diffusion is a highly effective strategy for simultaneous interface and bulk modification in PSCs.
• This approach is well-suited for the asymmetric structure of perovskites, leading to improved device performance.
• The method offers a simple and efficient route to fabricate high-performance perovskite solar cells.