Maskless micropatterning of electrochromic nanoparticles using a focused electron beam

Optical properties of electrochromic (EC) materials can be reversibly changed under applied voltages through electrochemical redox reactions. Prussian blue (PB) is a well-known EC material that changes color from blue to colorless and transparent, and vice versa. Fine patterning of PB particles on a transparent substrate could lead to the development of a high-quality display device with very low energy consumption. In this paper, a maskless patterning technique using a focused electron beam is described, and the effects of the accelerating voltage and the electron dose are studied. The results show that the micropatterning of PB particles is achieved at an accelerating voltage of 5 kV and at electron doses of 10–100 C/m2. Reversible changes in color were observed between blue and colorless–transparent after the patterning of PB particles.