Sealed pinholes prolong lifespan of perovskite solar cells

The method also enabled the team to precisely control how and when they added other ingredients to the mix to make it more conductive. The result again was a significant improvement—they could finely tune the energy level of that layer to closely match the layer beneath it, which makes the movement of 'holes' carrying positive charges around the solar cell circuit much easier.

"A very small difference between the top layer and perovskite material means maybe we get greater energy efficiency," said Jung.

The evaporation method also resulted in a much longer-lasting solar cell. Before, the cells would lose the ability to efficiently convert sunlight into electricity after a couple of days. Now, their efficiency remains high for more than 35 days.

While cheaper than conventional silicon-based solar cells, evaporation-based perovskite solar cells are more expensive than spin-coated cells. The team is now working to determine how to strike a balance between cost and efficiency, and hopefully find a way to use solution processing without creating pinholes.

- Paul Buckley
  EE Times Europe

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