| 摘要: | 近年來，有機光電材料因其在再生能源領域的潛力備受關注，成為科學界積極探索的重點方向。其中，有機π共軛小分子憑藉其優異的光電特性與電子傳輸能力，在有機電子元件中扮演關鍵角色。相較於高分子材料，π共軛小分子較容易透過官能基修飾來調整能隙，從而最佳化材料應用端的光電表現。
駢苯作為典型的有機π共軛小分子，在許多研究領域受到關注，其中以駢五苯廣泛應用於有機薄膜電晶體(OTFT)和有機場效電晶體(OFET)等領域。然而，駢五苯在空氣中易氧化，穩定性成為其發展的主要限制。為了改善此缺點，近期有研究發現，將駢芳香環引入雜原子(例如:O、N、S)所形成之駢芳香雜環可大幅提升分子的穩定性，因此使駢芳香雜環在有機光電材料領域中逐漸備受矚目。此外，在相關研究中，藉由延長駢芳香雜環之π-共軛系統，再加上駢環結構本身分子的高平面性，使整個分子更容易形成ππ 堆疊，有助於提高電子遷移率，使其在光電特性方面展現出更卓越的潛力。
有鑑於此，本研究致力於開發駢七芳香雜環( S,N-heteroheptacene )之新合成途徑，但目前針對駢七芳香雜環的合成研究相對較稀少，再者，此類高環數相駢的分子在鈣鈦礦太陽能電池中的應用仍未出現任何報導。因此，本研究以二噻吩并吡咯(dithienopyrrole, DTP)為起始物，利用省步驟之碳-氫/碳-氫自身耦合反應作為關鍵步驟來快速地製備新型的S,N-駢七芳香雜環，並探討其分子穩定性及應用。
然而，實驗結果顯示，以二噻吩並吡咯(dithienopyrrole, DTP)為起始物所合成之中間體及其衍生物具有熱不穩定性，導致產物在純化過程中發生分解，無法順利集量製備目標之駢七芳香雜環。因此，本研究進一步調整合成策略，改以相對穩定之二噻吩并噻吩(dithienothiophene, DTT)作為起始物，並採用有別於傳統的合成路徑，「先引入末端基團，再進行關鍵的合環步驟(將二噻吩並吡咯結構嵌入分子骨架中)」。最後以此新策略所合成之相關分子JXH02-03作為電洞傳輸層材料，實際應用於反式鈣鈦礦太陽能電池(inverted perovskite solar cells)，並對其光電特性進行分析，以探討其作為功能性材料的可行性。;In recent years, organic optoelectronic materials have attracted considerable attention due to their potential in renewable energy applications. Among them, π-conjugated small molecules play a vital role in organic electronic devices, offering advantages such as tunable energy gaps through functional group modification, which facilitates the optimization of device performance.
Pentacene, a representative π-conjugated molecule, has been widely used in organic thin-film transistors (OTFTs) and organic field-effect transistors (OFETs). However, its instability in air limits practical applications. To overcome this, incorporating heteroatoms (e.g., O, N, S) into the aromatic backbone to form heteroacene has been shown to improve molecular stability. These heteroacene also benefit from extended π-conjugation and high planarity, enhancing π-π stacking and charge mobility, making them promising for optoelectronic applications.
Motivated by these advantages, this study aims to develop a new synthetic route for S,N-heteroheptacene—a relatively unexplored class of compounds with no prior reports on their application in perovskite solar cells. Initially, dithienopyrrole (DTP)was used as a starting material, and a streamlined C-H/C-H direct coupling reaction was employed to construct the heteroacene core. However, the resulting intermediates showed poor thermal stability and decomposed during purification, preventing large-scale synthesis.
To address this, the synthetic route was revised using a more stable precursor, dithienothiophene (DTT). A nontraditional strategy was adopted: introducing terminal substituents first, followed by the key ring-fusion step to embed the DTP unit into the molecular backbone. The resulting compound, JXH02-03, was applied as a hole transport layer in inverted perovskite solar cells, and its optoelectronic properties were analyzed to assess its potential as a functional material. |
