TY - JOUR
T1 - Syntheses and characterization of carbazole based new low-band gap copolymers containing highly soluble benzimidazole derivatives for solar cell application
AU - Kim, Jaehong
AU - Park, Sung Heum
AU - Kim, Jinwoo
AU - Cho, Shinuk
AU - Jin, Youngeup
AU - Shim, Joo Young
AU - Shin, Hyunmin
AU - Kwon, Sooncheol
AU - Kim, Il
AU - Lee, Kwanghee
AU - Heeger, Alan J.
AU - Suh, Hongsuk
PY - 2011/1/15
Y1 - 2011/1/15
N2 - Newly designed 2H-benzimidazole derivatives which have solubility groups at 2-position have been synthesized and incorporated into two highly soluble carbazole based alternating copolymers, poly[2,7-(9-(1′-octylnonyl)-9H- carbazole)-alt-5,5-(4′,7′-di(thien-2-yl)-2H-benzimidazole-2′- spirocyclohexane)] (PCDTCHBI) and poly[2,7-(9-(1′-octylnonyl)-9H- carbazole)-alt-5,5-(4′,7′-di(thien-2-yl)-2H-benzimidazole-2′- spiro-4″-((2‴-ethylhexyl)oxy)-cyclohexane)] (PCDTEHOCHBI) for photovoltaic application. These alternating copolymers show low-band gap properties caused by internal charge transfer from an electron-rich unit to an electron-deficient moiety. HOMO and LUMO levels are -5.53 and -3.86 eV for PCDTCHBI, and -5.49 and -3.84 eV for PCDTEHOCHBI, respectively. Optical band gaps of PCDTCHBI and PCDTEHOCHBI are 1.67 and 1.65 eV, respectively. The new carbazole based the 2H-benzimidazole polymers show 0.11-0.13 eV lower values of band gaps as compared to that of carbazole based benzothiadiazole polymer, poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′, 7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT), while keeping nearly the same deep HOMO levels. The power conversion efficiencies of PCDTCHBI and PCDTEHOCHBI blended with [6,6]phenyl-C 71-butyric acid methyl ester (PC71BM) are 1.03 and 1.15%, respectively.
AB - Newly designed 2H-benzimidazole derivatives which have solubility groups at 2-position have been synthesized and incorporated into two highly soluble carbazole based alternating copolymers, poly[2,7-(9-(1′-octylnonyl)-9H- carbazole)-alt-5,5-(4′,7′-di(thien-2-yl)-2H-benzimidazole-2′- spirocyclohexane)] (PCDTCHBI) and poly[2,7-(9-(1′-octylnonyl)-9H- carbazole)-alt-5,5-(4′,7′-di(thien-2-yl)-2H-benzimidazole-2′- spiro-4″-((2‴-ethylhexyl)oxy)-cyclohexane)] (PCDTEHOCHBI) for photovoltaic application. These alternating copolymers show low-band gap properties caused by internal charge transfer from an electron-rich unit to an electron-deficient moiety. HOMO and LUMO levels are -5.53 and -3.86 eV for PCDTCHBI, and -5.49 and -3.84 eV for PCDTEHOCHBI, respectively. Optical band gaps of PCDTCHBI and PCDTEHOCHBI are 1.67 and 1.65 eV, respectively. The new carbazole based the 2H-benzimidazole polymers show 0.11-0.13 eV lower values of band gaps as compared to that of carbazole based benzothiadiazole polymer, poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′, 7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT), while keeping nearly the same deep HOMO levels. The power conversion efficiencies of PCDTCHBI and PCDTEHOCHBI blended with [6,6]phenyl-C 71-butyric acid methyl ester (PC71BM) are 1.03 and 1.15%, respectively.
KW - 2H-benzimidazole
KW - conjugated polymers
KW - copolymerization
KW - low-band gap polymer
KW - polymer solar cell
KW - thin films
UR - http://www.scopus.com/inward/record.url?scp=78650281853&partnerID=8YFLogxK
U2 - 10.1002/pola.24435
DO - 10.1002/pola.24435
M3 - Article
AN - SCOPUS:78650281853
SN - 0887-624X
VL - 49
SP - 369
EP - 380
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
IS - 2
ER -