Influences of Lignophenol-Derivatives on Performances of Photo-Chemical Cells

抄録

Hinoki Cypress (Chamaecyparis obtusa)-lignophenol (p-cresol type, HCLC), which is directly and quantitatively synthesized from wood through the phase-separation system, hydroxymethylated HCLC (HCLC-HM) and polymerized HCLC-HM by heat-set (HCLC-HM-P) were used as materials for photo-sensitizers for nano-porous TiO₂ electrodes. In order to investigate influences of structural features of lignophenol derivatives, HCLC, HCLC-HM and HCLC-HM-P were reacted under alkaline conditions at 140℃ (neighbouring group participation) and 170℃ (arylmigration). After these derivatives were investigated by ionization difference spectra using UV-Vis, FT-IR, ¹H-NMR and GPC, all derivatives were used as photo-sensitizers. There were different tendencies of HCLC from both HCLC-HM and HCLC-HM-P derivatives. As both HCLC-HM and HCLC-HM-P derivatives kept their polymeric structures, not only arylcoumaran or stilbene but also quinoid type structures acted as good photo absorbers. Based on these results, HCLC-HM-P-TiO₂ electrodes polymerized directly demonstrated V_oc = 0.48 V, I_sc = 4.00mAcm^-2, FF = 0.61 and η = 1.06 % under 100.0 mWcm^-2 of visible light irradiation. Especially I_sc was drastically improved. Moreover hardwood lignophenol showed same tendency.