Stabilizing Buried Interface by Introducing a Multifunctional Poly(hexamethylenebiguanide) Hydrochloride for...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Defects at the buried interface of perovskite films limit the stability and practical application of n-i-p perovskite solar cells (PSCs).
• Optimizing the buried interface is crucial for enhancing PSC performance, especially for flexible and extreme-environment applications.

Purpose of the Study:

• To optimize the SnO2/perovskite interface in PSCs using Poly(hexamethylenebiguanide) hydrochloride (PHMB).
• To improve the morphology of the SnO2 film, passivate oxygen vacancies, and suppress defects at the perovskite bottom surface.
• To enhance the stability and performance of PSCs for flexible and low-temperature applications.

Main Methods:

• Introduction of PHMB into the SnO2/perovskite interface.
• Characterization of interface interactions and film morphology.
• Performance testing of modified PSCs under various conditions, including low-temperature cycling and bending.

Main Results:

• PHMB effectively improved SnO2 film morphology, passivated oxygen vacancies, and suppressed perovskite bottom surface defects.
• PHMB-modified PSCs achieved a power conversion efficiency (PCE) of 25.06%.
• Unencapsulated rigid PSCs retained 92.42% efficiency after 120 low-temperature cycles (290-170 K).
• Flexible PSCs demonstrated excellent bending stability.

Conclusions:

• PHMB is an effective interfacial modifier for enhancing PSC performance and stability.
• The introduction of a polymer interface passivation layer, like PHMB, is a reliable strategy for PSCs in low-temperature and flexible environments.