Combining two nanotech methods for engineering solar cell materials appears to yield better results than either one does alone. In the race to make solar cells cheaper and more efficient, many researchers and start-up companies are betting on new designs that exploit nanostructures -- materials engineered on the scale of a billionth of a meter.

Lack of water causes great distress among the population in large parts of Africa and Asia. Small decentralized water treatment plants with an autonomous power supply can help solve the problem: They transform salty seawater or brackish water into pure drinking water. Large industrial plants for the desalination of seawater deliver 50 million cubic meters of fresh water every day -- particularly in the coastal cities of the Middle East. However, the technology is complex and consumes large amounts of energy.