Pressing effect in polymer solar cells with bulk heterojunction nanolayers

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Polymer solar cells (PSCs) are a promising renewable energy technology.
• The performance of PSCs is highly dependent on the morphology of the active layer.
• Optimizing the active layer morphology is crucial for enhancing power conversion efficiency.

Purpose of the Study:

• To investigate the effect of pressing the light-absorbing active layer on the performance of polymer solar cells.
• To determine the optimal pressing conditions (temperature and pressure) for maximizing PSC performance.

Main Methods:

• Active layers were prepared from solutions containing regioregular poly(3-hexylthiophene) and soluble fullerene molecules.
• A home-built micro-press system was used to press the active layers under controlled temperature and pressure.
• Surface morphology was analyzed using atomic force microscopy.
• Photovoltaic characteristics were measured under simulated solar light (AM 1.5 G, 100 mW/cm2).

Main Results:

• Pressing the active layer increased the dark current of the devices, irrespective of pressing temperature.
• The highest power conversion efficiency was achieved when the active layer was pressed under 10 kgf at 70 degrees C.
• Changes in surface morphology and thermophysical effects were identified as key factors influencing device performance.

Conclusions:

• Pressing the active layer is an effective method for enhancing polymer solar cell performance.
• Optimal pressing conditions can significantly improve power conversion efficiency by controlling active layer morphology.
• Further research into the thermophysical effects during pressing may lead to even greater performance gains.