Perhaps I missed this discussion in the article, but what are the theoretical advantages of these organic transistors over the traditional CMOS transistors motivating this research?
BTW "GHz speeds" isn't much. Transistors from the 1950s achieved this - such a metric is the "Gain-Bandwidth product" which means "GHz" is the frequency at which the gain has fallen unity (the transistor has ceased to be useful in ANY way - a resistor has comparable "performance").
In the 1980s I worked with 50 GHz Gain-Bandwidth bipolar transistors. Most microwave transistors today are well into 100-200 GHz.