Freezone 2.5 liter 84 c benchtop freeze dryer

First, an FTO-coated glass substrate (surface conductivity of 20 ohm) was pre-cleaned to remove dusts or possible oxidations. The substrate was sequentially sonicated for 20, 10, and 8 min in glass cleaning fluid, DI water, and IPA, respectively. Next, the substrate was dried in an 80 °C-oven for two hours. For printing, the cleaned substrate was placed on the sample stage, and a drop of photoresist was dispensed on it. Next, the laser focus array was generated in the photoresists by the holograms to fabricate the designed structures. After printing, the patterned substrate was post-processed in PGMEA for 15 min and then in IPA for 10 min. After development, the patterned substrate was dried in open air at room temperature. For fragile structures (e.g., free-standing wires of less than 300 nm-widths or metastructures that tend to distort by surface tension), a freeze dryer was used to maintain their shapes: The patterned substrate was immersed in DI water and frozen at −40 °C for 12 hours, which was then freeze-dried in a FreeZone 2.5 Liter −84C Benchtop Freeze Dryer from Labconco for another 12 hours.