藉由導電小分子之高效率有機/氧化鋅奈米柱混摻太陽能電池

Abstract

介面的性質是聚合物/金屬氧化物混摻太陽能電池的一項重要課題，其對有機太陽能電池效能的表現有著重大的影響。在本實驗中，我們選用2-萘硫醇（2-Naphthalenethiol，2-NT）這種可溶性的導電小分子作為修飾氧化鋅奈米柱表面的特性。接著在修飾過後的氧化鋅奈米柱上用旋轉塗佈的方式鋪上混和均勻的高分子（P3HT:PCBM）為主動層，最後鍍上銀電極完成元件。 我們發現此種分子會提升主動層和氧化鋅之間的相容性；能在氧化鋅表面鍵結形成電偶極，藉由此電偶極能夠有效的改善激子分離的效率並且加速電荷從主動層到氧化鋅奈米柱的轉移；以及能增加電荷傳輸網絡的路徑。這幾項優點能夠使得短路電流密度（Jsc）、開路電壓（Voc）和填充因子（FF）大幅提升，與未用此分子修飾過的太陽能電池元件相比，效率從 1.86％ 增加至 3.71％，整整提升100％，目前為止，我們的研究在全世界 ITO/ZnO-nanorod/ (P3HT:PCBM)/Ag 的系統下為最高的紀錄。

Interface property is one of the important issues in optimizing the performance of hybrid polymer/metal-oxide solar cells. We select a soluble conductive small molecule, 2-naphthalenethiol (2-NT), to modulate the surface property of the oriented ZnO-nanorod arrays before contacting with the polymer blend in an inverted hybrid solar cell configuration. This conductive molecule enhances the compatibility between polymer blend and metal-oxide; enlarges the exciton separation efficiency and subsequent charge transfer rate into the bulk of nanorods by the bond dipole field; improves the ordering of charge transport network. As a result, there is a substantial improvement in photocurrent, open circuit voltage, and fill factor leading to double the power conversion efficiency of the unmodified device from 1.86% to 3.71%. This value sets the record of the highest efficiency reported to date based on ITO/ZnO-nanorod/poly(3-hexythiophene):(6,6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM)/Ag configuration.