掌性分子插層二維材料對發光二極體之影響

Abstract

為了製備掌性發光二極體元件，本研究討論將掌性分子插層至多種二維材料(MoS2、MoSe2、WS2、WSe2)中，以形成二維材料-掌性分子複合材料。論文大致分為三個部分。第一部份是二維材料的剝離，首先透過超音波液相剝離技術破壞塊材中層與層之間的凡德瓦力，使二維材料分散在溶液中。剝離後的溶液的顏色改變，並且透過其吸收光譜、XRD等數據可確認獲得單層或少層二維材料。第二部份分別添加兩種掌性分子(Methylbenzylamine,MBA)和(Naphthalenemethylamine,NEA)的R型和S型的鏡像異構物(R/S-MBA, R/S-NEA)進二維材料分散液，經退火形成掌性分子與二維材料交替堆疊的異質結構，利用AFM、XRD、元二色光譜儀等儀器證實該異質結構的形成。第三部份是製備WSe2_R/S-MBA與WSe2_R/S-NEA元件，探討添加不同比例的掌性分子或退火時間對元件產生的影響，進而找出更好的元件製備參數。最後可發現，以WSe2_R-MBA作為電動傳輸層的元件隨著退火時間的增加，元件的量子效率有上升的趨勢，在退火10分鐘後，其平均量子效率從原本的2.65%提升至2.82%，同時該元件具有圓偏振電致發光訊號，可為發展具有掌性自旋選擇性功能的光電元件提供更多研究方向。To fabricate chiral light-emitting diode (LED) devices, this study investigates the intercalation of chiral molecules into various two-dimensional (2D) materials¬ namely MoS₂, MoSe₂, WS₂, and WSe₂ to form 2D material–chiral molecule hybrid composites. The thesis is divided into three parts. First, 2D materials are exfoliated using ultrasonic liquid-phase exfoliation, disrupting van der Waals forces and dispersing the materials in solution. Changes in solution color, along with absorption spectroscopy and X-ray diffraction (XRD), confirm the formation of monolayer or few-layer materials. Second, two types of chiral molecules—(R/S)-Methylbenzylamine (MBA) and (R/S)-Naphthalenemethylamine (NEA)—are added to the dispersions. After annealing, the chiral molecules and 2D materials form alternating heterostructures, verified by atomic force microscopy (AFM), XRD, and circular dichroism spectroscopy. Third, devices using WSe₂_R/S-MBA and WSe₂_R/S-NEA are fabricated to study how the proportion of chiral molecules and annealing time affect performance. Devices using WSe₂_R-MBA as the hole transport layer show improved quantum efficiency with increased annealing time from 2.65% to 2.82% after 10 minutes and exhibit circularly polarized electroluminescence, offering promising insights into chiral-induced spin selectivity (CISS) in optoelectronics.