Wearable Photovoltaics...

Ultra-thin solar cells are flexible enough to bend around small objects, such as the 1mm-thick edge of a glass slide, as shown here.
CREDIT: Juho Kim, et al/APL

Topics: Consumer Electronics, Electrical Engineering, Materials Science, Photovoltaics, Solar Power

WASHINGTON, D.C., June 20, 2016 -- Scientists in South Korea have made ultra-thin photovoltaics flexible enough to wrap around the average pencil. The bendy solar cells could power wearable electronics like fitness trackers and smart glasses. The researchers report the results in the journal Applied Physics Letters, from AIP Publishing.

Thin materials flex more easily than thick ones -- think a piece of paper versus a cardboard shipping box. The reason for the difference: The stress in a material while it's being bent increases farther out from the central plane. Because thick sheets have more material farther out they are harder to bend.

“Our photovoltaic is about 1 micrometer thick,” said Jongho Lee, an engineer at the Gwangju Institute of Science and Technology in South Korea. One micrometer is much thinner than an average human hair. Standard photovoltaics are usually hundreds of times thicker, and even most other thin photovoltaics are 2 to 4 times thicker.

AIP: Ultra-thin Solar Cells Can Easily Bend Around a Pencil, Catherine Meyers