摘要
Small molecule ladder-type heteroarenes IHBT-2F is designed and synthesized with strong electrondonating and molecular packing properties, where the central unit, fused thienobenzene-thienothiphene (IHBT), is attached with the strong electron-deficient 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (2FIC) as the end group. The counterpart IDBT-2F with indancenodibenzothiophene (IDBT) mainchain is sythesized for comparison, in which thieno[3,2-b]thiophene (TT) core of IHBT is replaced by benzene core. Relative to benzene-core IDBT-2F, TT-core IHBT-2F shows a much higher highest occupied molecular orbital energy level (IHBT-2F:-5.46 eV;IDBT-2F:-5.72 eV) and significantly redshifted absorption, due to the π-donor capability of the sulfur atom, the larger π-conjugation and stronger intermolecular π-π stacking. The as-cast organic solar cells (OSCs) based on blends of PTB7-Th donor and IHBT-2F acceptor without additional treatments exhibit power conversion efficiencies (PCEs) as high as 8.74%, which is much higher than that of PTB7-Th:IDBT-2F (6.73%).
Small molecule ladder-type heteroarenes IHBT-2 F is designed and synthesized with strong electrondonating and molecular packing properties, where the central unit, fused thienobenzene-thienothiphene(IHBT), is attached with the strong electron-deficient 2-(5,6-difluoro-3-oxo-2,3-dihydro-1 H-inden-1-ylidene)malononitrile(2 FIC) as the end group. The counterpart IDBT-2 F with indancenodibenzothiophene(IDBT) mainchain is sythesized for comparison, in which thieno[3,2-b]thiophene(TT) core of IHBT is replaced by benzene core. Relative to benzene-core IDBT-2 F, TT-core IHBT-2 F shows a much higher highest occupied molecular orbital energy level(IHBT-2 F:-5.46 e V; IDBT-2 F: –5.72 e V) and significantly redshifted absorption, due to the π-donor capability of the sulfur atom, the larger π-conjugation and stronger intermolecular π –π stacking. The as-cast organic solar cells(OSCs) based on blends of PTB7-Th donor and IHBT-2 F acceptor without additional treatments exhibit power conversion efficiencies(PCEs)as high as 8.74%, which is much higher than that of PTB7-Th: IDBT-2 F(6.73%).
基金
NSFC (21504058)
NSFC/RGC Joint Research Scheme No. N_CUHK418/17
Research Grant Council of Hong Kong (General Research Fund No. 14314216)
the beam time and technical supports provided by 19U2 beamline at SSRF, Shanghai
