| Summary: | 博士 === 國立臺灣科技大學 === 化學工程系 === 107 === First, a novel conjugated polymer, denoted as ECPblack is synthesized. ECPblack demonstrated unique electrochromic behavior with an ultrahigh contrast ratio (over 80%) in most of the visible region, boasting an ultrahigh integrated contrast ratio of 71.8% between 380 nm to 880 nm. The long conjugated pendant group (pyrene) in ECPblack enhances the absorption in the blue region in its second oxidized state and results in transmissive-to-black electrochromic switching between the neutral state and the oxidized state. On the other hand, a facile strategy in developing colorless-to-colorful switching electrochromic polyimides with very high contrast ratio were exemplified by PI-1a (colorless-to-black) and PI-2a (colorless-to-blue), which were incorporated with alicyclic nonlinear, twisted structures and adjusted conjugated electrochromophores. Their specific structures resulted in their loose chain stacking and conjugation break, which minimized the charge transfer complex formation. It is noted that, by controlling the conjugation length of electrochromophore, the colorless-to-black switching ECP film (PI-1a) exhibited an ultrahigh integrated contrast ratio (Δ%Tint) up to 91.4% from 380 to 780 nm (96.8% at 798 nm). In addition, PI-1a films with asymmetric structure also demonstrated fast electrochemical and EC behaviors (a switching and bleaching time of 1.3 s and 1.1 s, respectively) due to the loose chain stacking, which provided more pathways for the penetration of counterion (ClO_4^-). Moreover, the colorless-to-black EC device based on PI-1a revealed an overall Δ%Tint up to 80%.
Second, a novel concept of electrode buffer layer material, exhibiting either hole transporting or reducing electrode work function (WF) properties, is demonstrated by the example of a polymeric compound PDTON, which can be utilized as a ‘universal’ electrode (either for anode or cathode) buffer layer material. Depending on the composition ratio of acetic acid and ethyl acetate upon dispersing, PDTON forms two kinds of nanospheres, serving as building blocks and defining the morphology and properties of the respective materials, termed as A-PDTON and C-PDTON. These materials are suitable for hole transport (triphenylamine on the surface of A-PDTON nanospheres) and reducing the WF of electrode due to the formation of suitable interfacial dipole (C-PDTON), respectively. The application of A-PDTON and C-PDTON on organic solar cells, organic light-emitting diodes and perovskite solar cells, comparable or even exceeding performance could be obtained.
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