Area-selective surface modification of si substrates with a fluorescent organophosphonic acid using the differences in reactivities of their surface terminal groups

Area-selective surface modification of Si substrates bearing OH- and H-terminated areas by fluorescent 1-pyrenylphosphonic acid (PYPA) was achieved using chlorobenzene at 140 °C for 2 h in an autoclave. The OH-terminated area was successfully modified, as shown by X-ray photoemission spectroscopy and contact angle measurement, while no reaction proceeded between PYPA and the H-terminated area. SiO₂ nanoparticles were reacted with PYPA under the same conditions to form SiOP bonds, suggesting that dehydration coupling proceeded between the OH-terminated area and PYPA.