| 초록 |
To improve photovoltaic device performance, donor-acceptor typed copolymers are promising because of their low absorption band-gaps that induce increased spectral overlap. Four low band-gap copolymers, PehCDT-BiT(poly-2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-4,7-bithiazole), PocCDT-BiT(poly-2,6-(4,4-bis-(2-octyl)-4H-cyclopenta[2,1-b; 3,4-b']-dithiophene)-alt-4,7-bithiazole), PehCDT-TZ(poly-2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-thiazolothiazole) and PocCDT-TZ(poly-2,6-(4,4-bis-(2-octyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-thiazolothiazole) are designed for investigating side chain effect and back-bone structure effect on film morphology and on carrier mobility. Polymers including TZ acceptor unit show better performance than those with BiT because TZ induces rigid back-bone structure and thereby increased conjugation length. PehCDT-TZ shows well-ordered nano-morphology and post-annealed effect. |
