Ex 200

Figure 1(a) shows a schematic of a fabricated transistor device. We first deposited a 30-nm-thick aluminum (Al) layer on a glass substrate (Corning Eagle XG, Germany) using vacuum deposition (EX-200, ULVAC, Japan). The substrate was then anodized in 1 mM of citric acid to grow an aluminum oxide (AlO_x) layer. In the next step, the substrate was immersed in 3 mM of dodecylphosphonic acid (C₁₂H₂₇O₃P) for 12 h at 30 °C, followed by rinsing in isopropyl alcohol and drying with nitrogen gas that produced a self-assembled monolayer (SAM) of dodecylphosphonate on the substrate. The fabrication process was followed by a vacuum deposition of a 30-nm-thick layer of pentacene molecules, which was deposited at the rate of 0.2 Å/s. Finally, a 50-nm-thick gold layer was deposited on these substrates through a shadow mask to fabricate source/drain contacts followed by an annealing of the device at 100 °C for 1 h under vacuum. The channel length and width of the transistor device were 40 µm and 500 µm, respectively. We fabricated two devices using sublimated and non-sublimated pentacene molecules under the same fabrication conditions.

Triptycene films were formed by TVE and BC. TVE was carried out using an ULVAC EX200, and the film thickness was monitored using a quartz-crystal microbalance. BC was carried out using a custom-made deposition system in ambient air. The triptycene powder was dissolved in mesitylene (Wako chemicals) to obtain a 0.5 mM solution. The blade was made of glass. All substrates were heated to 50–60 °C with a silicone-rubber heater while depositing the triptycene/mesitylene solution. The blade speed was fixed to between 40 and 50 µm/s. In the present study, the TVE-Trip process required approximately 1 h, including the evacuation and cooling time, while the BC-Trip process required approximately 8.5 or 17 min for substrate areas of 2 × 3 cm² and 4 × 5 cm², respectively. After forming triptycene films by TVE and BC processes, all the substrates were annealed at 120 °C for 1 h under vacuum at around 100 Pa.

Interdigitated electrodes were fabricated on films or mesh substrates via vacuum deposition. The film was a 75 µm thick polyimide (UPILEX‐75S, Ube Industries) or a 1.4 µm thick PET film (Mylar 1.4 CW02, DuPont Teijin Films). The PET film was attached in advance to a polyimide film (1020RM‐S, Okamoto Industries) with an adhesive layer. This adhesive polyimide film served as a supporting substrate to ease the handling of the 1.4 µm PET film during device fabrication. 70 nm gold was deposited on films or mesh substrates through a film mask using EX‐200 (ULVAC). The interdigitated electrode was 1 cm long, and 400 µm wide with 13 fingers. The spacing between adjacent fingers was 400 µm.