本研究主要以benzothiadiazole (BT)單元衍生開發數種有機光電材料。首先BT兩端接上噻吩延長共軛，接著以進行Cadogan cyclization與否衍生出具三環或五環兩種核心，再於結構末端上修飾推電子基triphenylamine (TPA)，製備出兩種小分子材料：DTPBT-2D (1)、DTBTN-2D (2)；或與SBT單元進行共聚製備出與兩種高分子材料：DTPBT-SBT (3)、DTBTN-SBT (4)。 本研究所開發之材料主要作為電洞傳輸層材料，應用於鈣鈦礦太陽能電池。在三環核心結構中引入拉電子能力較強之硝基將提升分子內電荷傳輸能力；五環核心則為稠環結構，其較平面之特性使分子間之 - 堆疊更強。小分子系列之兩材料DTPBT-2D (1)、DTBTN-2D (2) 均為D-A-D結構，此種分子設計能使分子內、間之載子傳輸更為順暢；高分子系列之兩材料DTPBT-SBT (3)、DTBTN-SBT (4)中之共聚單體SBT具硫醚鏈與鄰近噻吩間之硫---硫作用力，將增強分子的共振與平面性。此外，分子結構中含有氮與硫原子，其孤對電子能鈍化鈣鈦礦層中未配位之鉛離子。以上種種優點使此兩系列分子均具成為高效能光電材料之潛力。目前DTPBT-2D (1)、DTBTN-2D (2) 兩材料應用在錫基鈣鈦礦電池中，初步得到的元件效率為6.2% 與5.6%。 這些新材料皆完成NMR與質譜之結構鑒定，利用UV-Vis及DPV測量其光學及電化學性質如HOMO、LUMO與Eg，再以DSC及TGA證實此材料的高熱穩定性。這些新開發的有機光電材料正進行相關元件測試，期望有良好的效能表現。 ;A series of new organic optoelectronic materials based on benzoselenadiazole (BT) were developed and characterized for the applications in perovskite solar cells (PSCs). In this work, four newly developed HTMs (DTPBT-2D (1), DTBTN-2D (2), DTPBT-SBT (3), DTBTN-SBT (4)) were synthesized by conjugating DTPBT and DTBTN core to triphenylamine (TPA) or polymerizing with dithioalkylbithiophene (SBT). So far, the state-of-the-art hole-transporting materials (HTMs) with benzothiadiazole unit have been widely used in high effiency PSCs. Benefit from the strong electron withdrawing ability which derived from nitro groups, DTBTN core can afford good intramolecular charge transfer phenomenon. Intermolecular - interaction is enhanced due to the fused ring structure of DTPBT core, and the good solubility is maintained by introducing branched alkyl chain to the planar core. For the development of polymeric HTMs, highly planar structures can be obtained due to the intramolecular S---S interactions between thioalkyl chain and sulfur atom on the adjacent thiophene. Furthermore, the presence of electron rich sulfur and nitro atoms exhibit a good interaction with undercoordinated Pb2 ions and passivate the trap states in the perovskite films. Based on the above advantages, these newly developed compounds are expected to perform well in PSCs. Currently, DTPBT-2D (1) and DTBTN-2D (2) have been applied in tin-based perovskite solar cell, and the devices exihibited power conversion efficiency of 6.2% and 5.6%, respectively. The chemical structures of these newly developed materials were characterized by NMR spectroscopy and mass spectrometry. Further, the optical properties of these compounds were investigated by UV-Vis spectroscopy, electrochemical analyses were analyzed by DPV, and the thermal stabilities were determined by DSC and TGA. Optoelectronic devices made from these newly developed small molecules are under optimization.
