Gaussian Distribution of the Charge Traps in the Energy Gap of MDMO-PPV and Its Dependence on Synthesis Route Revealed by the Thermally Stimulated Current Spectroscopy

摘要

Energetical distribution of the charge traps was investigated in MDMO-PPV ([poly-(2-methoxyl),5-(3,77dimethyloctyloxy)] paraphenylenevinylene). The thermally stimulated current spectroscopy was applied as a direct photoelectrical method immediately related with charge transport and trapping in materials with defect states. Possibility of the selective trapping states filling by the light with different spectra below and above the band gap was demonstrated. The analysis revealed the Gaussian distribution of the traps in the energy gap. The sensitivity of the technique is evidenced by the results, indicating that in MDMO-PPV synthesized by different routes - Gilch and Sulfinyl - different defect states were identified.