MEH-PPV之薄膜製備對於其電荷載子遷移率之影響

Abstract

本實驗中，以氯苯(Chlorobenzene)、甲苯(Toluene) 作為MEH-PPV(poly[2-(2-ethylhexyloxy)-5-methoxy-1,4-phenylene vinylene])主要的溶劑。由於這兩種溶劑的極性程度不同，導致成膜過程中分子堆疊不同，使得其物理性質亦會跟著改變。另外，改變成膜方式;例如:一般製備法、外加電場製備法，或是利用高溫退火(anneal)的方式來改變共軛高分子的聚集效應，這些方式會影響在MEH-PPV薄膜中電荷載子傳導的行為模式。因此，利用電荷載子遷移率(Charge carrier mobility)、螢光光譜(PL spectrum)來分析這些MEH-PPV薄膜，以找出關連性並且討論這些方法對於光電元件的優劣性。

In this work, two solvents, toluene and chlorobenzene, are used for dissolving MEH-PPV. The physical properties will be different during solvent evaporation for drop cast films due to the different polarity between toluene and chlorobenzene. Besides, different film fabrication processes will give an opportunity to change, said, molecular packing. As a result, this will change the optical properties and electronic properties such as charge carrier mobilities. Different film fabrication of as-cast film and “E-cast” film for both toluene and chlorobenzene solutions were made for charge mobility measurements. The results indicate charge mobility will increase for “E-cast” films compare to normal as-cast films. The corresponding photoluminescence spectra reveal that the “E-cast” films are structureless (amorphous). This result is quite different from that of small molecules and inorganic devices.