Preparation and optical properties of amorphous silica doped with porphins of free-base by the two step sol-gel process

Kazukaka Kamitani, Motohiro Uo, Kazuki Morita, Hiroyuki Inoue, Akio Makishima

Research output: Contribution to journalConference article


Tetraphenylporphinetetrasulfonic acid (TPPS), which is known as a photochemical holeburning (PHB) dye, was incorporated in silica gels obtained by the sol-gel process from tetraethoxysilane (TEOS). The form of TPPS must be free-base (H 2P), which exists in basic condition, to be active in PHB. In this study to obtain transparent and dense silica gels doped with free-base TPPS, two-step hydrolysis process using solutions containing NaOH or using ammonia were developed. In the 1st step we used acidic catalyst to get denser and trasparent gels and in the 2nd step basic catalyst was adopted to obtain free-base TPPS. Monolithic silica gels can be obtained by this two-step process from the hydrolysis of TEOS. By the spectroscopic analysis of TPPS incorporated in the gels, it is found that free base form of TPPS is retained at the molar ratio of NaOH/TEOS above 10-3. And the spectra of monocation are observed at the molar ratio of NaOH/TEOS below 10-3. And the dimerization of TPPS incorporated in the TEOS gels does not occur higher NaOH concentration than that in the TMOS gels.

Original languageEnglish
Pages (from-to)255-263
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - Oct 13 1994
EventSol-Gel Optics III 1994 - San Diego, United States
Duration: Jul 24 1994Jul 29 1994



  • Dimerization
  • Free-base
  • PHB
  • Porphin
  • Sol-gel process
  • TPPS

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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