Electronic structures of sulfur-containing organic electronic materials probed by X-ray absorption spectroscopy

X線吸収分光法による含硫黄有機物質の電子構造

池浦 広美*; 関口 哲弘  

Ikeura, Hiromi*; Sekiguchi, Tetsuhiro

X線吸収端に観測される複数のピーク群(X線吸収端近傍微細構造、NEXAFS)は物質の空軌道伝導バンドの部分状態密度に関する情報を含んでいる。本発表では放射光X線を用いることにより、電荷移動性を示すチオフェン誘導体分子の薄膜試料の硫黄K殻吸収端領域のNEXAFSスペクトルを測定した。X線共鳴吸収について分子軌道法に基づく電子遷移の帰属を試み、スペクトルと電導的性質との相関関係に関する考察を行った。

Many peaks are observed in X-ray absorption fine structure near the inner-shall edges. Such fine structures are called near-edge X-rays absorption fine structure or abbreviated as NEXAFS. NEXAFS spectra provide us with information on property of electronic states concerning partial density of states of unoccupied conduction band for materials. In this work, we have investigated several sulfur-containing thiophene derivative polymers using NEXAFS spectroscopy. We have recorded the S K-edge NEXAFS spectra of film samples of these electronic materials and tried to interpret the origin of electronic transition seen in NEXAFS on the basis of molecular orbital theory. Furthermore, we discuss whether there is a potential relation between the observed spectra and charge-transfer property of the materials.