| 摘要: | 本研究係以二噻吩並吡咯並苯並噻二唑 (DTPBT)為核心，開發新型有機光電材料，應用於鈣鈦礦太陽能電池中。所採用之DTPBT分子具有五併環稠環結構，具備高度平面性與雙吡咯單元，提升分子內電荷傳輸效率。
第一系列材料於 DTPBT 核心一端引入推電子基三苯胺 (TPA)，另一端修飾具自組裝能力之錨定基團，包括丙二腈 (MN)、氰甲基磷酸二乙酯 (PE)、磷酸 (PA)，以提升分子排列穩定性，合成出三種新型電洞傳輸層 (HTM)自組裝材料 (Self Assembled Monolayers, SAM)：DTPBT*-MN (2)、DTPBT*-PE (3)、DTPBT*-PA (4)。上述材料均透過SAM技術形成薄膜，與實驗室先前開發之DTPBT*-CA (1) (氰基乙酸，CA)進行比較。初步測試DTPBT*-CA (1) 在 Pb-PSC 中光電轉換效率 (PCE)達 19%，其餘材料元件測試中。
第二系列進一步於TPA上引入氟以改良第一系列。氟原子具高電負度，除可調控分子能階、增進載子傳輸能力，亦可與鈣鈦礦層中未配位金屬離子形成鍵結以鈍化缺陷。配合不同錨定基團 (CA、MN、PE、PA)，設計出四種新型SAM材料：DTPBT*F-CA (5)、DTPBT*F-MN (6)、DTPBT*F-PE (7)及DTPBT*F-PA (8)。以氟修飾 TPA 後，所得之SAMs分子之HOMO能階如預期地較未氟化者低。
所有材料皆經核磁共振光譜 (NMR)與質譜 (MS)鑑定結構，並以紫外可見光光譜 (UV-Vis)及差式脈衝伏安法 (DPV)分析其光學與電化學特性。亦經由差示掃描量熱法 (DSC)與熱重分析 (TGA)驗證其熱穩定性。目前，本論文所開發之SAM材料正進行元件測試中。
;In this study, novel organic optoelectronic materials based on dithienopyrrolobenzothiadiazole (DTPBT) were developed and applied in perovskite solar cells (PSCs). The DTPBT molecule features a fused five-ring system with high planarity and dual pyrrole units, which enhances intramolecular charge transport efficiency.
In the first series of material designs, the electron-donating triphenylamine (TPA) group was introduced at one end of the DTPBT core, while various self-assembling anchoring groups, including malononitrile (MN), cyanomethyl diethyl phosphate (PE), and phosphoric acid (PA), were attached at the other end to improve molecular packing stability. Three novel self-assembled monolayer (SAM) hole-transport materials (HTMs) were synthesized： DTPBT*-MN (2), DTPBT*-PE (3), and DTPBT*-PA (4). These new SAMs were compared with our previously developed DTPBT*-CA (1), which contained a cyanoacetic acid (CA) anchoring group. All materials are capable of forming thin films via SAM techniques. Preliminary device tests showed that DTPBT*-CA (1) achieved a power convension efficiency (PCE) of 19% in Pb-based PSCs.
Fluorine atoms were further introduced into the TPA unit to modify the First series. Due to their high electronegativity, fluorine atoms are capable of lowering the HOMO energy level to better match the Perovskite (PSK) layer. In addition, fluorine may passivate defects by coordinating with the under-coordinated metal ions in the perovskite layer. Incorporating different anchoring groups (CA, MN, PE, PA), four new SAM materials were designed：DTPBT*F-CA (5), DTPBT*F-MN (6), DTPBT*F-PE (7), and DTPBT*F-PA (8). As expected, with a fluorine addition in the TPA, the HOMO of the new SAMs indeed are lower in comparison with those non-fluorinated ones.
The structures of all synthesized materials were confirmed by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Their optical and electrochemical properties were analyzed using ultraviolet-visible (UV-Vis) spectroscopy and differential pulse voltammetry (DPV). In addition, thermal stability was verified by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The newly developed HTMs are currently undergoing device testing. |
