Improved Interfacial Electron Dynamics with Block Poly(4-vinylpyridine)-Poly(styrene) Polymers for Efficient and...

Area of Science:

• Materials Science
• Photovoltaics
• Polymer Chemistry

Background:

• Dye-sensitized solar cells (DSSCs) are emerging for indoor photovoltaic applications.
• Key factors for high photocurrent conversion efficiency (PCE) include rapid electron injection, extended excited dye lifetime, and suppressed back electron recombination.

Purpose of the Study:

• To investigate block copolymers of poly(4-vinylpyridine) and poly(styrene) (P4VP-b-PSt) as performance enhancers for DSSCs.
• To evaluate the impact of polymer molecular structure on electron injection, recombination, and overall photovoltaic performance.

Main Methods:

• Synthesis and characterization of P4VP-b-PSt block copolymers.
• Fabrication and testing of DSSCs incorporating the synthesized copolymers.
• Performance evaluation under standard AM 1.5G and LED light conditions.
• Stability testing using ISOS-D1 (dark) and ISOS-L2 (light soaking) aging protocols with common electrolytes.

Main Results:

• P4VP67-b-PSt23 and P4VP67-b-PSt61 copolymers achieved PCEs of 10.0% and 9.8% under AM 1.5G, and notably 19.4% and 16.4% under 1000 lx LED light.
• The copolymers demonstrated stable PCEs with standard iodide/triiodide electrolytes in both acetonitrile and 3-methoxypropionitrile solvents.
• Long-term stability was confirmed under both dark and continuous light soaking conditions.

Conclusions:

• P4VP-b-PSt block copolymers effectively accelerate electron injection and suppress recombination in DSSCs.
• These polymers significantly enhance PCE, particularly under indoor lighting conditions, and offer long-term operational stability.
• The study highlights the potential of tailored polymer structures for advancing DSSC technology.