“The performance of these transistors has improved dramatically over the past 10 years,” says Henning Sirringhaus, chief scientist at Plastic Logic and professor of physics at Cambridge University. Even so, as researchers made transistors that matched or beat the performance of amorphous silicon–the material used to make the transistors that control most displays on the market–the challenge for the company was to translate these results to practical manufacturing.
Bringing organic electronics to the market has been difficult because there aren’t any companies making the equipment needed to work with them. These materials can be printed with ink jets or on giant rolls of plastic–and as long as they’re printed at a small scale, says Sirringhaus, it’s possible to get good results. Developing manufacturing-scale processes with good results took Plastic Logic many years. No equipment manufacturers sell these printing systems, says Paul Semenza, senior vice president at DisplaySearch, a market research company.
Sirringhaus says that the company uses a combination of existing and new processes to make the electronics at its factory in Dresden, Germany. “That was a big challenge for Plastic Logic,” he says. “We had some pieces of equipment we couldn’t buy.” The company does not disclose the details of its manufacturing process, but Sirringhaus says many challenges had to be overcome. Printing on plastic is challenging because it distorts during the printing process, and printed materials tend to seep into the substrate. If the material is heated too much, the plastic shrinks. Plastic Logic uses a roll-to-roll printing process to make the transistor arrays in large volumes, and at this level it’s important to ensure that all the layers of the material line up properly as they’re printed.
The Que will be an important test of the market demand for the technology. However, says Semenza, it might also be a one-off. “When one company is creating its own process from scratch, it’s very difficult to make that a mass product for two reasons: equipment producers don’t have a big enough customer base, and there is no shared learning–multiple companies going down the same path benefits everybody.”
“Many of the players in organic electronics are watching the Que carefully,” Sirringhaus says. “If it succeeds, they will have confidence that organics can work.”
Meanwhile, Plastic Logic is looking to reduce the cost of printing the electronics, and may develop flexible devices in the future. The company is also looking into new materials to further improve the performance of the transistor arrays, says Sirringhaus, and may partner with companies making color pixel arrays.