A.)低能隙高分子應用於高分子太陽能電池之研究 B.)添加劑對於提升有機高分子太陽能電池光電特性之研究

Abstract

本篇論文中係利用兩種新的施體-受體共聚高分子，PCTDBI與PBDTPP，混掺不同比例的PCBM與PC71BM製作出混摻異質接面高分子元件，並藉由改變不同溶劑與加入不同添加劑對表面形貌的影響進行探討，希望能同時以低能隙高分子其對光的吸收範圍增加與不同之元件製程方法，將高分子太陽能電池元件效果提升至最佳化。 使用PCTDBI製成之高分子太陽能電池其主動層表面形態隨著使用不同的溶劑有顯著差異，並隨著選用不同沸點之溶劑來改變揮發速率使表面形貌均勻,進而增加共軛高分子與PCBM之接觸面積，減少電子電洞對之再結合現象，使元件效率由1.0%提升至1.8%。 使用PBDTPP製成的高分子太陽能電池除了選用不同溶劑來製備元件外，並且選用不同添加劑來改善主動層之表面形態。其主動層經由添加劑加入後，元件之填充因子由0.35%提升至0.54%，另因添加劑加入使原本聚集之高分子分散，增加異質介面接觸面積，提升載子移動率，短路電流密度由4.95 mA/cm2提升至10.7 mA/cm2，兩倍電流密度以上的增加，再經過不同混摻比例、膜厚的元件最佳化參數調整過後，元件效率由1.2%提升為3.30%。

Two novel polymers, PCDTBI and PBDTPP, based on donor-acceptor copolymers have been designed for application in polymer solar cells (PSCs). PCDTBI exhibits a band gap of 1.75 eV to match the maximum photon flux of sunlight after incorporating a planar imidazole structure into the polymeric main chain. Electrochemical measurement reveals large enough offset of lowest unoccupied molecular orbital (LUMO) for efficiently transfer electron to PCBM. The solar cell devices fabricated with PCTDBI/PCBM at blend ratio of 1:2 by weight exhibited a short-circuit current (Jsc) of 5.89 mA/cm2 and power conversion efficiency of 1.20%. Whereas, PCTDBI/PC71BM at weight ratio of 1:2 exhibited a short-circuit current of 6.46 mA/cm2 and power conversion efficiency of 1.84%. We also fabricated solar cell devices based on PBDTPP /PC71BM, which exhibits an unfavored morphology of aggregation. Thus we incorporating additives into polymer solution in order to control surface morphology. The power conversion efficiency(PCE) of the PSCs based on PBDTPP/PC71BM (1:1, wt/wt) improved from 1.17% to 3.30% which polymer blend dissolve in DCB/DIO system, Jsc from 4.95 mA/cm2 to 10.7 mA/cm2, an open circuit voltage of 0.60 and fill factor from 0.36 to 0.51 under AM 1.5G illumination.