Dopant-Free Pyrene-Based Hole Transporting Material Enables Efficient and Stable Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Dopant-free hole transporting materials (HTMs) are crucial for the long-term stability of perovskite solar cells (PSCs).
• Developing efficient and stable HTMs is key to advancing PSC technology.

Purpose of the Study:

• To design and synthesize a novel star-shaped arylamine HTM, Py-DB, for dopant-free PSCs.
• To investigate the structure-property relationships of Py-DB and its impact on PSC performance and stability.

Main Methods:

• Synthesis of a novel star-shaped arylamine HTM (Py-DB) with a pyrene core and carbon-carbon double bonds.
• Fabrication and characterization of perovskite solar cells using Py-DB as the HTM.
• Performance testing including power conversion efficiency (PCE) and long-term stability under controlled environmental stress.

Main Results:

• The Py-DB HTM exhibits enhanced intermolecular π-π stacking, improved solubility, higher hole mobility, and better film morphology compared to a reference material.
• Py-DB-based PSCs achieved a record power conversion efficiency of 24.33% for dopant-free small molecular HTMs in n-i-p configuration.
• The devices demonstrated excellent long-term stability, retaining over 90% of initial efficiency after 1000 hours of humidity and heat stress.

Conclusions:

• The novel Py-DB HTM significantly improves the efficiency and stability of perovskite solar cells.
• The star-shaped molecular design and extended conjugation are effective strategies for developing high-performance dopant-free HTMs.
• This work offers valuable insights for designing efficient and reliable HTMs for future photovoltaic applications.