二氧化鈦奈米柱與氧化鎢層組成之混成式光電元件以提升元件特性

Abstract

本研究之目的在於結合二氧化鈦奈米柱與氧化鎢層以製備反結構光電元件並提升其效率。利用水熱法在氟摻雜之二氧化錫(FTO)基板上製備不同長度之二氧化鈦奈米柱，長度短於200 nm之二氧化鈦奈米柱於可見光波段之穿透率高於80%。製作結構為FTO/TiO2 nanorods/Ionic PF/MEH-PPV/PEDOT:PSS/WO3/Au之反結構發光元件，最佳元件效果為使用長度100 nm之TiO2奈米柱，其最大亮度及電流效率各為4,493 cd/m2及0.66 cd/A，相較於以緻密層及較長之奈米柱作為電子傳輸層而言具有更佳的元件效益。 製作結構為FTO/TiO2 nanorods/Ionic PF/P3HT:PC61BM/ PEDOT:PSS/WO3/Au之反結構混成式高分子太陽能元件，並以P3HT:PC61BM作為主動層。最佳元件為使用長度600 nm之TiO2奈米柱搭配氧化鎢薄膜分別做為電子傳輸層與電洞萃取層；該元件之開路電壓、短路電流密度、填充因子及功率轉換效率分別為0.56 V、6.8 mA/cm2、55%及2.08%。相較於緻密層及奈米粒子製作之元件，以二氧化鈦奈米柱製作元件之短路電流密度及效率值較高。此部分亦利用含吡咯併吡咯二酮團基之聚噻吩衍生物作為主動層以製作太陽能元件，其開路電壓、短路電流密度、填充因子及功率轉換效率分別達到0.56 V、8.53 mA/cm2、52%及2.48%。以上結果說明二氧化鈦奈米柱具有應用於光電元件之潛力。

The goal of this research is to prepare inverted optoelectronic devices with improved performance by combining titanium dioxide (TiO2) nanorods and tungsten trioxide (WO3) layer. TiO2 nanorods with different lengths were established directly on the fluorine-doped tin oxide (FTO) substrates by the hydrothermal method. The prepared TiO2 nanorods with lengths shorter than 200 nm possess transmittance higher than 80% in the visible range. Inverted light-emitting devices with the configuration of FTO/TiO2 nanorods/Ionic PF/MEH-PPV/PEDOT:PSS/WO3/Au were constructed. The best device based on 100 nm-height TiO2 nanorods achieved a max brightness of 4,493 cd/m2 and current efficiency of 0.66 cd/A, revealing much higher performance compared with those using TiO2 compact layer or nanorods with longer lengths as electron transporting layers. Inverted hybrid polymer solar devices with the configuration of FTO/TiO2 nanorods/Ionic PF/P3HT:PC61BM/PEDOT:PSS/WO3/Au were fabricated, using P3HT:PC61BM as the active layer. The best device performance was obtained by using 600 nm-height TiO2 nanorods and WO3 layer as electron transporting and hole extraction layer, respectively; the open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), and power conversion efficiency (PCE) were 0.56 V, 6.8 mA/cm2, 55%, and 2.08%, respectively. Comparing with devices using TiO2 compact layer and nanoparticles, the devices based on TiO2 nanorods showed higher JSC and PCE values. In this part, the polythiophene derivative containing 1,4-diketopyrrolopyrrole were also used as the active layer for the fabrication of solar devices, and the the corresponding VOC, JSC, FF, and PCE reached 0.56 V, 8.53 mA/cm2, 52%, and 2.48%, respectively. All above results demonstrate the potential of TiO2 nanorods for the application in optoelectronic devices.