Ultrasensitive solution-cast quantum dot photodetectors

A practical solution The best electronic and optoelectronic devices are built via semiconductor crystal growth on a single-crystal substrate. Over 100 papers have been published in recent years in Nature on alternative devices, produced instead from the solution phase. They have some advantages over conventional crystalline semiconductor devices: ease of fabrication, physical flexibility and — most important — low cost. The problem was the poor electronic performance of solution-processed devices, compared with single-crystal counterparts. But that could change now: a team from the University of Toronto reports that one such system — colloidal quantum dots of lead sulphide — can actually outperform the state-of-the-art crystalline alternative.