Cheaper solar cells with greater efficiency in the offing

Scientists led by an Indian-origin researcher have developed a solar-panel material that can cut down on photovoltaic costs while achieving competitive power-conversion efficiency of over 20 per cent.
Some of the most promising solar cells today use light-harvesting films made from perovskites - a group of materials that share a characteristic molecular structure.
However, perovskite-based solar cells use expensive 'hole-transporting' materials, whose function is to move the positive charges that are generated when light hits the perovskite film.
Scientists from the Swiss Federal Institute of Technology (EPFL) have engineered a considerably cheaper hole-transporting material that costs only a fifth of existing ones while keeping the efficiency of the solar cell above 20 per cent.

They developed a molecularly engineered hole-transporting material, called FDT, that can bring costs down while keeping efficiency up to competitive levels.
Tests showed that the efficiency of FDT rose to 20.2 per cent - higher than the other two, more expensive alternatives. And because FDT can be easily modified, it acts as a blueprint for an entire generation of new low-cost hole-transporting materials, researchers said.

"The best performing perovskite solar cells use hole transporting materials, which are difficult to make and purify, and are prohibitively expensive, costing over 300 pounds per gram preventing market penetration," said Mohammad Nazeeruddin from EPFL who led the study.

"By comparison, FDT is easy to synthesise and purify, and its cost is estimated to be a fifth of that for existing materials - while matching, and even surpassing their performance," he added.
There are currently only two hole-transporting materials available for perovskite-based solar cells. Both types are quite costly to synthesise, adding to the overall expense of the solar cell, researchers said.
The findings were published in the journal Nature Energy.