| Autor: |
Fujimura, Takuya, Shimada, Tetsuya, Sasai, Ryo, Takagi, Shinsuke |
| Zdroj: |
Clays and Clay Minerals; 20240101, Issue: Preprints p1-8, 8p |
| Abstrakt: |
To identify the mechanisms for and to estimate the photochemical reaction efficiency of molecules in solid-state host materials is difficult. The objective of the present research was to measure the photogeneration efficiency of the methylviologen cation radical (MV+•) hosted in a semi-transparent hybrid film composed of MV2+and saponite, a 2:1 clay mineral. MV+• is the one-electron reduced species of MV2+. MV+• was generated by UV irradiation of these films. The fluorescence intensity of MV2+and the photogeneration efficiency of MV+• depended on the loading level of MV2+. When the loading level of MV2+was high (75% of the cation exchange capacity (abbreviated as % CEC) of saponite), its fluorescence was reduced considerably because of the self-fluorescence quenching reaction, and the photogeneration efficiency of MV+• was relatively high (quantum yield φ = 3.5×10–2) compared to that of films with low adsorption density (10% CEC, φ = 1.1×10–2). Furthermore, when the loading level of MV2+was very low (0.13% CEC), a self-fluorescence quenching reaction was not observed and MV+• was not generated. From these observations, one of the principal mechanisms of the self-quenching reaction and MV+• formation in saponite is the electron transfer reaction between excited MV2+and adjacent MV2+molecules in the ground state. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
