Self-assembly polymers could hold key to low-cost solar cells

The photovoltaic devices created in a project led by Rice chemical engineer Rafael Verduzco and Penn State chemical engineer Enrique Gomez are based on block copolymers, self-assembling organic materials that arrange themselves into distinct layers. They are claimed to outperform other cells with polymer compounds as active elements and the discovery is detailed online in Nano Letters.

While commercial, silicon-based solar cells turn about 20 per cent of sunlight into electricity and experimental units top 25 per cent, there’s been an undercurrent of research into polymer-based cells that could greatly reduce the cost of solar energy, Verduzco said in a statement. The Rice-Penn State cells reach about three per cent efficiency, a figure claimed to outperform results achieved in other labs.

‘You need two components in a solar cell: one to carry (negative) electrons, the other to carry positive charges,’ Verduzco said. The imbalance between the two prompted by the input of energy – sunlight – creates useful current.