Ultralow-Cost Lacunary Metal-Oxo Framework Enables Efficient and Stable Organic Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Organic solar cells (OSCs) with p-i-n architecture offer tunable energy levels via organic interfacial layers (ILs), but suffer from limited operational lifetime due to morphological instability of organic electron-transporting layers (ETLs).
• Organic ETLs face challenges including high costs and batch-to-batch variations, hindering commercialization.

Purpose of the Study:

• To develop a stable, cost-effective, and high-performance inorganic ETL for p-i-n OSCs.
• To enhance electron extraction and overall device performance and longevity.

Main Methods:

• Synthesized an inorganic lacunary-structure metal-oxo framework (BSiW9) for use as an ETL.
• Employed a hydroquinone-derivative dopant (HQ) to enhance the redox activity and electrical conductivity of the BSiW9 ETL.
• Fabricated and characterized p-i-n OSC devices incorporating the novel inorganic ETL.

Main Results:

• The BSiW9 ETL demonstrated ultralow cost and significantly enhanced electron extraction.
• Doping with HQ reinforced electrical conductivity, leading to a power conversion efficiency (PCE) of 20.5% in p-i-n OSCs.
• The champion device exhibited outstanding long-term stability, retaining 92% of its initial efficiency after 1250 hours of operation.

Conclusions:

• Rationally designed inorganic metal-oxo frameworks are effective as interfacial layers for improving OSC performance and stability.
• The developed BSiW9 material offers a promising, low-cost alternative to organic ETLs, advancing the industrial compatibility of OSCs.