We report here a novel phenomenon: selective metal deposition on photoswitchable diarylethene (DAE) surfaces. Magnesium vapor was deposited by vacuum evaporation on the colored DAE but not on the uncolored surface. The selective deposition originates in the change of the glass transition temperature of the amorphous DAE film resulting from photoisomerization and therefore from changes of surface molecular motion. We clarified that Mg atoms on the uncolored surface actively migrated on the surface and were desorbed from the surface. The possibility of depositing other metals is also discussed. Light-controllable metal-integrated deposition was demonstrated as a new function of the photoswitchable molecular surfaces. This study reveals new features of the photoswitchable molecular surfaces, and their potential suggests bright prospects for future applications in organic electronics.

Selective metal deposition controlled by light irradiation was achieved for Zn, Mg, and Mn on a photochromic diarylethene (DAE) film; metal vapor atoms were deposited only on the colored film but not on the uncolored film. The deposition properties of the metals were strongly dependent on the deposition rates. Fine metal patterns were produced by laser scanning and a conventional vacuum-evaporation method without a shadow mask. Multiple-metal pattern preparation of Zn, Mg, and Mn via a maskless evaporation in a single vacuum process was also demonstrated.Organic electronic devices, which have advantages for various applications due to low cost, light weight, and flexibility, have been studied widely. 16 A vacuum-evaporation method with a shadow mask 7 or an ink-jet-printing process with metal nanoparticles 8 is generally used to prepare electrodes or wiring for the devices. However, it is difficult to further improve their resolution due to the complexity of the setup with a shadow mask system, or of thermal damage to the organic layer during heat treatment in an ink-jet-printing method.We have reported light-controllable selective Mg deposition on photochromic diarylethene (DAE) surfaces, where metal Mg atoms are deposited on a colored DAE surface but not on an uncolored surface by a vacuum-evaporation method.9,10 Photochromism is defined as a reversible change in color induced by light irradiation.11 The selective Mg deposition originates from large glass-transition temperature (T g ) change in the amorphous organic film in response to photoreaction. 9,12 An essential factor of the selective Mg deposition is desorption of Mg atoms from the uncolored surface due to active surface-molecular motion caused by the low T g . Mg is an important cathode material in organic electronics, 1315 and therefore the selective Mg deposition can be applied to fine cathode preparation for organic devices. 16,17 For a variety of industrial applications containing electronics and optics, the selective deposition of various metal species is desirable. We report here the selective deposition of Zn and Mn as well as Mg, and demonstrate metal pattering controlled by light irradiation with maskless vapor deposition. Results and DiscussionSelective Metal Deposition. Interaction of Metals and Deposition Rate Dependence: Figure 1 shows a photoisomerization of DAE. Selective Mg deposition means that an Mg film is formed on the colored DAE surface while not at all formed on the uncolored DAE surface by vacuum evaporation. Selectivity in Mg deposition is correlated with the difference in the T g of the DAE in its colored and uncolored states. The colored amorphous state has a T g of 95°C, whereas the uncolored state 32°C. Because the interaction between Mg atoms and DAE surface molecules such as van der Waals' force is weak, Mg is desorbed from the uncolored surface by thermal energy even at ambient temperature.9 Therefore, we tested the selective deposition for other metals such as Ca, Al, Mn, and Ag, simply by evaporating those metals to ...