應用苯并呋喃於主鏈予體－受體高分子之總體異質接面太陽能電池元件研究

Abstract

在本研究中，我們選用一系列含有苯并呋喃為電子受體之主鏈予體－受體型共軛高分子，應用於總體異質接面太陽能電池製程最佳化之研究。 苯并呋喃(benzooxadiazole, BO)為一具有強拉電子能力的共平面環結構，以其做為共軛高分子之受體，使此系列高分子材料具有許多助於增加元件效率的性質。 與苯并二噻吩(benzodithiophene)共聚合之PBDTBO具有良好之熱穩定性，相當高之分子量 (Mn= 62kg mol-1)，好的溶解度及較低的HOMO能階，在製成太陽能電池元件後，具有好的光電轉換效率5.7 %。和一系列噻吩衍生物共聚之高分子PTHBO、PBTTBO、PTTTBO，其具有結晶特性與低的HOMO能階，其中PTHBO之太陽能電池元件可獲得高的開路電壓1.02 V，PBTTBO由於高結晶度特性，可獲得相當高之填充因子(FF= 0.74)，PTTTBO在經由熱處理製程後可獲得好的光電轉換效率5.3 %。與一系列強推電子基團并雙噻吩及其衍生物共聚之高分子PCyTBO、PCySiTBO、PCyNTBO具有寬廣之吸收(300至700 nm)，有利於吸收較多之光子，其中PCySiTBO和PC71BM混摻並利用添加劑之製程後，其太陽能電池之光電轉換效率可達到5.0 %。

In this study, we selected a series of main chain donor-acceptor conjugated copolymers which synthesize by BO acceptor and different donor units for application in polymer bulk heterojunction(BHJ) solar cells. Benzooxadiazole (BO) is a rigid, electron-deficient, coplanar ring structure as an acceptor moiety and this series of polymer materials have many of the characteristics to improve the device efficiency. PBDTBO with high thermal decomposition temperature, good solubility, high molecular weight (Mn=62kg mol-1), and low HOMO energy level .A BHJ solar cell device provided a high power conversion efficiency(PCE) of 5.7 %. Second, we used a series of thiophene-based conjugated copolymers PTHBO, PBTTBO, and PTTTBO which showed excellent crystallinity. The PTHBO devices showed a high Voc of 1.02 V. With a highly crystallinity, PBTTBO had a high fill factor of 74%. PTTTBO showed a good PCE for 5.3 % with thermal annealing process. Finally, we used a series of conjugated copolymers featuring alternative C-, Si-, and N-bridged dithiophene-based building blocks and BO units. These polymers exhibit broad absorption in the visible range (300－700 nm) to absorbe more photon. PCySiTBO blend with PC71BM exhibited a good PCE value of 5.0 % by an additive process.