Photovoltaic technology developed at the University of Exeter, UK, offers the potential to harvest three times the energy compared with conventional solar cell systems. The method uses the atomically thin semiconductor hafnium disulfide oxidized with a high-intensity UV laser to funnel electrical charge onto a chip.

Such inverse funneling facilitates extraction of charges away from the strain region. With common semiconductors, the required strain levels cannot be achieved as the materials would break if strained more than 1 percent. A new class of semiconductors — transition-metal dichalcogenides — can reach strain levels up to 15 percent.

The inverse charge funneling effect and associated strain gradient were demonstrated to enhance the responsivity of a phototransistor of up to 350 percent. The development could lead to the design of highly efficient and lightweight solar cells.

The research is published in Nature Communications.