Realizing Over 13% Efficiency in Green-Solvent-Processed Nonfullerene Organic Solar Cells Enabled by 1,3,4-Thiadiazole-Based Wide-Bandgap Copolymers

Designer polymers make for safer solar cells

7 June 2018

Plastic-based solar cells that are inexpensive and lightweight can now be fabricated in ways that reduce exposure to harmful solvents.

By replacing poorly soluble ‘buckyball’ molecules traditionally employed as solar energy harvesters with pentagonal, ring-shaped molecules known as thiadiazoles, researchers from Sichuan University have made an organic photovoltaic device that combines an enviable power conversion efficiency with straightforward production.

The thiadiazoles were combined with another polymer that is designed to absorb infrared light and then incorporated into nanoscale-thin films. Intriguingly, the new organic solar cells performed better when the conventional chlorinated liquids used to dissolve the polymers were replaced with less-toxic hydrocarbon alternatives.

The team found that the mix of carbon, nitrogen and sulfur atoms inside polymerized thiadiazoles helped produce electronic states favourable for absorbing visible light. Stacking these thin films into a prototype device yielded near-record conversion efficiencies for plastic photovoltaics.

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References

1. Advanced Materials 30, 1703973 (2018). doi: 10.1002/adma.201703973