Optical recording performance of thin films of phthalocyanine compounds

As organic dyes with excellent thermal and light stability, phthalocyanine compounds have been investigated as write-once read-many optical recording materials. By selecting different substituents and metallic ions, the absorption bands of thin film of phthalocyanine compounds were matched with the wavelengths of semiconductor lasers. It was found that the absorption regions of vacuum sublimated thin films of vanadyl phthalocyanine (VOPc), tetra-pentyloxy phthalocyanine vanadyl (TPPcVO) and tetra-nonyloxy phthalocyanine vanadyl (TNPcVO) were between 580 and 850 nm. In the near-IR region, the absorbance and reflectivity of thin films of VOPc were greater than 50% and 20% respectively. The static optical recording test of the VOPc thin film showed that the write power was less than 10 mW with the write pulse width of 200 ns using an He-Ne laser as light source. The dynamic optical recording test of VOPc as a write-once read-many recording material on a 5.25 in optical disk indicated that the carrier-to-noise ratio (CNR) was greater than 45 dB.