photoresist tagged posts

3-dimensional microstructures can be written using a laser, erased, and rewritten. Credit: KIT

3D printing by direct laser writing produces micrometer-sized structures with precisely defined properties. Researchers of Karlsruhe Institute of Technology (KIT) have now developed a method to erase the ink used for 3D printing. In this way, the small structures of up to 100 nm in size can be erased and rewritten repeatedly. This development opens up many new applications of 3D fabrication in biology or materials sciences, for instance.

Direct laser writing means that a computer-controlled, focused laser beam generates the structure in a photoresist similar to a pen...

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

The flexible photovoltaics could power wearable electronics like fitness trackers and smart glasses. “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.

They made the ultra-thin solar cells from semiconductor gallium arsenide. They stamped the cells directly onto a flexible substrate without using an adhesive that would add to the material’s thickness...