共軛高分子中非均向性電洞遷移率之研究

Abstract

在本文中，我們製造並量測了有機發光二極體(所謂的三明治結構)以及電極平行於共軛高分子薄膜的二維結構(水平結構)的電洞遷移率，以比較共軛高分子在垂直方向以及水平方向的電荷傳輸機制的差異。我們發現在同一電場下水平結構的電洞遷移率可以較垂直結構大上四個數量級，另外藉由量測電洞遷移率對於溫度的關係，我們發現水平結構及垂直結構的電場係數γ以及活化位能Δ並無相當大的差異，最主要的差異是來自於μ*，即每一次載子跳躍後所能傳遞的距離，並藉由FET元件和水平元件來探討載子密度和遷移率的關係，我們發現遷移率和載子密度並無明顯的關聯性，而是和集聚體有高度的關聯性，再由旋轉塗佈的轉速和電洞遷移率的關係，我們確定了這種不均勻性的來源。

In order to compare the carrier transportation mechanism in both vertical and horizontal direction, we fabricate PLED (sandwich structure) and horizontal structure device which electrode parallel to the conjugated polymer film and measure the hole mobility. It is found that for a fixed electric field the horizontal mobility is about four orders of magnitude larger than the vertical mobility. By measuring the hole mobility at different temperature, we obtain that electric field coefficient γ and activation energy Δ is not much different between horizontal and vertical direction. The only major difference is μ* which reflect the real space distance for each hopping. We also discuss the relation between mobility and carrier density by FET and horizontal device. There is no obvious link between charge density and mobility but aggregate. The relation between spin speed and mobility determine the anisotropic origin.