ポリ(3-ドデシルチオフェン)を用いた高分子発光素子に対する光照射効果

Photoirradiation effects on a polymer light-emitting device (PLED) from poly(3-dodecylthiophene)(PAT12) with an ITO/polymer/semitransparent-A1 structure have been studied. The effects found in the device from PAT12differ from those found in a device from a poly(p-phenylene vinylene) derivative: the external quantum efficiency of emission from the device as well as the emission intensity at a constant voltage decreases upon photoirradiation. Moreover, while the emission from a PLED based on PAT12diminished upon a photoirradiation in air for several minutes, no notable indication of photooxidation is found in a PAT12film that suffered such a photoirradiation. These suggest that the quenching of the luminescent species by photooxidized defects, rather than the reduced charge transport ability of the polymer, plays a dominant role to diminish the emission.ポリ(3-ドデシルチオフェン)(PAT12)を用いたITO/高分子/半透明A1構造の高分子発光素子に対する光照射効果を調べた。PAT12を用いた場合、ポリ(p-フェニレンビニレン)誘導体を用いた素子との相違が見られた：一定電圧における発光強度だけではなく、発光の量子効率までもが光照射によって減少した。さらに、数分間の光照射によって発光は検出されなくなる一方で、光吸収スペクトルの減少は極めて僅かであった。以上の結果は主鎖の切断によるキャリア輸送の阻害ではなく、光酸化欠陥による発光種の消光が劣化の主要因であることを示唆する