Researchers crack thermal stability barrier in organic solar cells
Scientists have engineered organic solar panels that remain stable at temperatures above 200°C—a breakthrough that could extend device lifespan and reduce manufacturing costs. The advance uses a fullerene alloy blend that maintains performance during high-heat processing, addressing a major obstacle preventing organic photovoltaics from competing with silicon-based solar technology.
Originaltitel: A fullerene alloy based photovoltaic blend with a glass transition temperature above 200 degrees C
<p>Organic solar cells with a high degree of thermal stability require bulk-heterojunction blends that feature a high glass transition, which must occur considerably above the temperatures encountered during device fabrication and operation. Here, we demonstrate for the first time a polymer : fullerene blend with a glass transition temperature above 200 degrees C, which we determine by plasmonic nanospectroscopy. We achieve this strong tendency for glass formation through the use of an alloy of neat, unsubstituted C-60 and C-70, which we combine with the fluorothieno-benzodithiophene copolymer PTB7. A stable photovoltaic performance of PTB7 : C60 : C70 ternary blends is preserved despite annealing the active layer at up to 180 degrees C, which coincides with the onset of the glass transition. Rapid deterioration of the power conversion efficiency from initially above 5% only occurs upon exceeding the glass transition temperature of 224 degrees C of the ternary blend.</p>