三苯胺及其衍生物與吡咯并吡咯二酮之交替型與無規則型共聚高分子合成、特性及其於有機太陽能電池應用上之研究

Abstract

本研究乃合成共軛主鏈結構為施體-受體(Donor-Acceptor)之低能隙共軛高分子並利用Suzuki coupling和Stille coupling合成法成功的合成一系列交替型共聚高分子(Alternating copolymer)及無規則共聚高分子(Random copolymer)。 此研究中採用的施體為具有良好電洞傳輸能力的三苯胺(Triphenylamine)基團且本身的螺旋結構，可導致材料不易產生結晶，非結晶的特色使得材料電荷傳遞各個方向都具有均一性，另外這種扭曲開來的結構也會使得材料本身的溶解度提升。除此之外，我們也在三苯胺的側鏈上分別接枝上無機三苯基矽和有機咔唑並探討其物理性質和光電特性上有何差異；受體方面選用具有較剛硬的結構、高共平面性、高熱穩定性及高電子親和力的吡咯并吡咯二酮(Diketopyrrolopyrrole，DPP)結構，藉由吡咯並吡咯二酮高共平面特性可稍稍補足三苯胺共平面性的不足以補償在非晶相向中電子傳遞的損失，另一方面其強拉電子的特性以增加電子傳遞效率。 然而就單單只有施體-受體(Donor-Acceptor)交替所形成的共聚高分子，通常其紫外光-可見光之吸收光譜都不會呈現寬廣的吸收範圍，因此我們預期透過無規則共聚合(Random copolymerization)的方式引入不同含量的3-已烷基噻吩(3-hexylthiophene) 改善交替型共聚高分子的可見光吸收範圍，以盡可能地達到全光譜吸收。如此一來，便能提升高分子材料的短路電流值。此外我們對成功合成出的一系列交替型共聚高分子(PTPA-DPP、PTPASiPh3-DPP、PTPACz-DPP)以及無規則共聚高分子(TPASiHTDPP系列和TPACzHTDPP系列)利用凝膠滲透層析儀、熱重分析儀、微差掃描卡計、紫外光/可見光分光光譜儀、以及循環伏安儀來做光電性質分析與探討，進而應用於有機太陽能電池元件的製作與討論。

In order to obtain conjugated polymers of low energy band gap we formed the conjugated main chain structure of the donor-acceptor alternately. Donor and acceptor successfully synthesized by a series of alternating copolymers and random copolymers via Suzuki coupling reaction and Stille coupling reaction. In this research, We used triphenylamine as donor because of its great hole transporting property and helical structure. Triphenylamine can increase open circuit voltage(Voc) for organic polymer solar cell. In addition, we mounted triphenyl silicon and carbazole on side chain of triphenylamine and investigated the physical properties and photovoltaic performance of all kinds of polymer. Diketopyrrolopyrrole (DPP) was chosen as a acceptor because of its characteristic: a strong electron withdrawing monomer and light harvesting covering a wide spectrum of UV-Vis absorption. Especially,the properties of DPP unit were coplanarity and a closer π-π stacking distance that would enhance the charge mobilities. The alternating donor-acceptor strategy was the frequently observed shifting of the polymer absorption profile to the long wavelength region as opposed to a true broadening across both the visible and near-infrared regions. Therefore, we expected that different contents of 3-hexylthiophene could improve the visible absorption range of alternating copolymers and to achieved full spectral absorption. In addition,we successfully synthesized a series of alternating copolymers and random copolymers which used gel permeation chromatography, thermal gravimetric analysis, differential scanning calorimetry, UV / Vis spectrophotometer, and cyclic voltammetry to analysis their properties of optical band gaps、HOMO and LUMO. As a result all kinds of copolymer applied to the production of organic polymer solar cell and investigated characteristic of organic polymer solar cell . The highest power conversion efficiency were 3.16 %, containing weigh ratio with random copolymer(TPASi15HT75DPP10) : PC71BM = 1:2 , Voc of 0.64 V, Isc of 8.29 mA/cm2, and FF of 0.59 under AM 1.5G solar simulator