Spectroscopic and dielectric studies of meso-tetrakis(p-sulfonatophenyl) porphyrin doped hybrid borate glasses

Hybrid borate glasses containing different concentrations of meso-tetrakis(p-sulfonatophenyl) porphyrin sodium salt (TPPS4) were prepared. The obtained glass samples were found to be transparent and homogeneous. Formation of TPPS4-J-aggregates in borate glass was investigated by means of optical absorption, steady state and time resolved fluorescence spectroscopy. The hybrid glasses exhibit a strong S2→S0 emission at ∼473 nm and J-aggregates show emission at ∼733 nm. Time resolved fluorescence show two exponential decay with lifetime of τ1 = 65 ± 10 ps (∼80%) and τ2 = 3.87 ± 0.1 ns (∼20%) respectively. Dielectric properties such as dielectric constant (ɛ′), dielectric loss (tan δ) and ac conductivity (σac) over a range of frequency and temperature of these glasses were studied. The ac conductivity was found to be proportional to ωs (where s < 1). The observed change in dielectric parameters due to different concentrations of TPPS4 has been analyzed in light of different polarization mechanisms.

Research highlights▶ meso-Tetrakis(p-sulfonatophenyl) porphyrin sodium salt (TPPS4) doped hybrid borate glasses were prepared by rapid melt quenching technique. ▶ The formation of TPPS4-J-aggregates in the borate glass was studied by optical absorption, steady state and time resolved fluorescence emission techniques. ▶ The temperature and frequency dependence of dielectric loss and dielectric constant in the hybrid glass systems have been measured. ▶ Conductivity is found to be highly dependent on temperature and frequency.