ultra-thin sun cells can without problems bend around a pencil

The bendy photovoltaics, made through researchers in South Korea, could power wearable electronics.

Scientists in South Korea have made ultra-thin photovoltaics flexible enough to wrap across the average pencil. The bendy solar cells may want to power wearable electronics like fitness trackers and smart glasses. The researchers document the effects in the magazine carried out Physics Letters, from AIP Publishing.

thin substances flex greater easily than thick ones -- suppose a piece of paper versus a cardboard delivery box. The motive for the distinction: The pressure in a cloth while it's being bent will increase farther out from the valuable plane. due to the fact thick sheets have extra cloth farther out they're harder to bend.

"Our photovoltaic is set 1 micrometer thick," stated Jongho Lee, an engineer on the Gwangju Institute of science and generation in South Korea. One micrometer is an awful lot thinner than a median human hair. preferred photovoltaics are commonly masses of instances thicker, or even most different thin photovoltaics are 2 to four instances thicker.

The researchers made the extremely-skinny sun cells from the semiconductor gallium arsenide. They stamped the cells at once onto a flexible substrate with out the use of an adhesive that could add to the fabric's thickness. The cells had been then "cold welded" to the electrode at the substrate via applying stress at a hundred and seventy stages Celcius and melting a top layer of fabric referred to as photoresist that acted as a transient adhesive. The photoresist changed into later peeled away, leaving the direct metal to metal bond.

The metal bottom layer additionally served as a reflector to direct stray photons again to the solar cells. The researchers examined the performance of the tool at converting daylight to electricity and determined that it turned into comparable to comparable thicker photovoltaics. They done bending assessments and observed the cells ought to wrap around a radius as small as 1.four millimeters.

The team also carried out numerical evaluation of the cells, finding that they experience one-fourth the quantity of stress of comparable cells which are 3.five micrometers thick.

"The thinner cells are less fragile beneath bending, however carry out similarly or maybe slightly higher," Lee stated.

a few different agencies have suggested solar cells with thicknesses of round 1 micrometer, but have produced the cells in extraordinary approaches, as an example through casting off the entire substract by means of etching.

by using switch printing as opposed to etching, the brand new method developed with the aid of Lee and his colleagues can be used to make very bendy photovoltaics with a smaller amount of substances.

the skinny cells can be integrated onto glasses frames or material and may electricity the following wave of wearable electronics, Lee said.