Synthesis of novel diketopyrrole and selenophene containing nir absorbing polymers and their application in bulk-heterojunction solar cells

Öklem, Gülce
DPP-based conjugated polymers are recently used in organic light emitting diodes, electrochromic devices, organic field effect transistor and organic solar cell applications. Their advantageous properties, such as broad optical absorption in Near Infra Red (NIR) region, high charge carrier mobility and good film forming ability make them an excellent choice for generation of highly efficient solar cells. In this thesis, using donor-acceptor approach (D-A) we aimed to synthesize novel polymers with furan based DPP units as the acceptor and selenophene as the donor. Modulating the alkyl side chains on furan based DPP cores, we obtained three different monomers which coupled with selenophene via Stille Coupling. Oxidation and reduction behaviors of the synthesized polymers were studied with cyclic voltammetry. Optical absorption properties of the polymers were investigated. Bulk heterojunction solar cell application of one of these polymers, P3 was performed with polymer/PCBM (1:3) ratio and the devices were fabricated with the structure ITO/PEDOT:PSS/P3:PCB71M/LiF/Al. Additionally, Inverted type bulk heterojunction solar cell application of P3 was also performed with device structure ITO/ZnO/P3:PC71BM/MoOx/Ag. While 3.00 % conversion efficiency was observed for the normal structure, a respectable 6.16 % efficiency was reached in the inverted structure with 3% diphenylether additive. This is one of the highest PCE reported for DPP based polymers.


Synthesis, electrochemical characterization and organic solar cell applications of selenophene containing conjugated polymers
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Donor-Acceptor (D-A) type conjugated polymers are very popular for potential applications such as organic light emitting diodes, solar cells, electrochromic devices and organic field effect transistors. In literature, cyclopentadithiophene and its derivatives are commonly used electron donor units for organic solar cells. The incorporation of selenium atom into polymer backbone results in low band gap polymers as compared to sulfur and oxygen counterparts. In this study, selenophene containing conjugated po...
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Varlıoğlu, Figen; Günbaş, Emrullah Görkem; Department of Polymer Science and Technology (2017)
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Benzothiadiazole is one of the most widely used acceptor units in Donor–Acceptor copolymers for organic solar cells (OSCs) with its strong electron withdrawing ability. It is also known that fluorine atom substitution directly to the backbone of conjugated polymers can improve the important parameters such as power conversion efficiency (PCE), open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) of OSCs. Besides benzothiadiazole, benzotriazole is another acceptor moiety whic...
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Citation Formats
G. Öklem, “Synthesis of novel diketopyrrole and selenophene containing nir absorbing polymers and their application in bulk-heterojunction solar cells,” M.S. - Master of Science, Middle East Technical University, 2017.