有機太陽能電池開路電壓之提升與探討

Abstract

本論文探討了影響在聚三己烷塞吩(P3HT)與苯基碳61丁酸甲酯(PCBM)混合型太陽能電池中之開路電壓的因子與增進開路電壓之方法，使用X光電子頻譜(XPS)等儀器來進行介面分析，以探討製程處理對元件之介面影響以及原件效能改善之背後機制。 本論文第一部分討論了倒置結構元件照光以及過濾主動層溶液處理後元件效能的改善，使用X光電子頻譜探測電子受體材料PCBM在主動層底部的含量，發現照光和過濾過後的元件之PCBM含量較多，此P3HT聚集在上表層而PCBM沉積於底部之垂直相分離現象會使得倒置結構之陰極接觸面更為理想，改善倒置結構的開路電壓和元件效率，卻使正規結構的開路電壓和元件效能變差。 在第二主題中嘗試了串疊型太陽能電池的結構來提升整體元件的開路電壓，此部分串聯了P3HT:PCBM混合型底層子電池和小分子上層子電池，並成功的將整體元件之開路電壓提升至1.025V，此部分仔細探討了單層小分子電池和串疊型太陽能電池之製程。

In this thesis, methods that can influence and enhance open circuit voltage in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyruc acid methyl ester (PCBM) bulk heterojunction have been investigated. The improvement of the device performance was studied in conjunction with the surface analysis by X-ray photoemission spectroscopy to understand the influence of the critical interfaces in organic photovoltaic. In the first topic, we discussed the vertical phase separation induced by illumination during measurement and the filtration of active layer solution. The devices, going through the two treatments, exhibited an enhancement in open circuit voltage and a better power conversion efficiency. XPS was applied to estimate the ratio of PCBM at the bottom surface of the blend film. In the second topic, we tried to improve open circuit voltage by stacking two organic solar cells to implement a tandem solar cell in series. A high Voc of 1.025V was achieved, which is almost the sum of the polymer bottom cell and the small molecule top cell. The fabrication procedures for the single-layer small-molecule solar cell and tandem cell were discussed in detail in this topic.