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Wide band-gap organic molecules containing benzodithiophene and difluoroquinoxaline derivatives for solar cell applications
摘要： Two new semiconducting organic small molecules, namely BDTQ-BDT(EH) and BDTQ-BDT(OC), were prepared by attaching electron accepting 2,3-didodecyl-6,7-difluoro-5,8-di(thiophen-2-yl)quinoxaline (DTQ) unit on 2,6-position of electron donating 4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b’]dithiophene (BDT(EH)) and 4,8-bis(octyloxy)-benzo[1,2-b:4,5-b’]dithiophene (BDT(OC)) units. Molecule BDTQ-BDT(EH) showed higher thermal stability (5% weight loss temperature, Td “349 jC), slightly lower band-gap (Eg “2.10 eV) and deeper highest occupied molecular orbital energy level (HOMO “–5.36 eV) level compared to those (Td “336 jC, Eg “2.11 eV, and HOMO “–5.30 eV, respectively.) of the molecule BDTQ-BDT(OC). The organic solar cells (OSCs) made with the synthesized molecules as an electron donor and [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) as an electron acceptor gave a maximum power conversion efficiency (PCE) of 1.20% and 0.83%, respectively, for BDTQ-BDT(EH) and BDTQ-BDT(OC). This study confirmed that the substituents attached on the 4,8-position of BDT unit greatly alter the properties of the resulting molecules.
关键词： small molecule solar cells,wide band-gap molecules,quinoxaline-based molecules,benzodithiophene-based molecules,organic solar cells
更新于2025-09-16 10:30:52
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Benzodithiophene Hole‐Transporting Materials for Efficient Tin‐Based Perovskite Solar Cells
摘要： Developing efficient interfacial hole transporting materials (HTMs) is crucial for achieving high-performance Pb-free Sn-based halide perovskite solar cells (PSCs). Here, a new series of benzodithiophene (BDT)-based organic small molecules containing tetra- and di-triphenyl amine donors prepared via a straightforward and scalable synthetic route is reported. The thermal, optical, and electrochemical properties of two BDT-based molecules are shown to be structurally and energetically suitable to serve as HTMs for Sn-based PSCs. It is reported here that ethylenediammonium/formamidinium tin iodide solar cells using BDT-based HTMs deliver a champion power conversion efficiency up to 7.59%, outperforming analogous reference solar cells using traditional and expensive HTMs. Thus, these BDT-based molecules are promising candidates as HTMs for the fabrication of high-performance Sn-based PSCs.
关键词： benzodithiophene,tin,perovskite solar cells,triphenylamine,lead-free
更新于2025-09-11 14:15:04
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A systematic evaluation of triisopropylsilylethynyl-substituted thienyl side chain effects on series of benzo[1,2-b:4,5-b′]dithiophene based polymer donors and their photovoltaic performances
摘要： In this report three new donor copolymers based on alternate octyl 3-fluorothieno[3,4-b]thiophene-2-carboxylate as acceptor and benzo[1,2-b:4,5-b′]dithiophene (BDT) derivatives having triisopropylethynylsilane (TIPS), triisopropyl((thiophen-2-yl)ethynyl)silane (TIPS-Th) and triisopropyl((3-octylthiophen-2-yl)ethynyl)silane (TIPS-ThC8) side chains as donors, (respectively named as P1, P2 and P3) are synthesized to assess whether insertion of thiophene or alkyl thiophene units between TIPS side chains and BDT backbones can improve their properties and photovoltaic performance. Indeed, the modification of TIPS side chains on BDT backbone found to distinctly affect their opto-electrochemical properties, molecular orientations and nanoscale morphologies in resultant polymers. Among the polymers, optimized organic solar cells (OSCs) of P1:PC71BM exhibited best power conversion efficiency (PCE) of 6.55% with very high VOC of 1.02 V, thereby outperforming P2 and P3 (PCE of 4.72% and 5.47%, respectively). The detailed characterization of optimized blends revealed that this superior device performance of P1:PC71BM blend films attributed to their compact and “face-on” molecular orientation, high hole mobility and superior nanoscale morphology, which minimized voltage loss and leading to an efficient charge transfer with low recombination losses in OCSs. In contrast, lower performances of P2 and P3 were mainly originating from their decreased solubilities caused by the insertion of TIPS-Th or TIPS-ThC8, thereby negatively affecting their molecular weights, morphology and charge carrier mobilities. Thus, these results provide a valuable guideline for designing polymers based on 2-TIPSTh substituted BDT units.
关键词： Organic solar cells,TIPS-BDT,benzodithiophene,donor polymers,TIPS effect
更新于2025-09-11 14:15:04
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π-Dimerization ability of conjugated oligomer dication diradicaloids composed of dithienylpyrrole and benzodithiophene units
摘要： 2+ composed of 2,5- di(2- thienyl)- N- 2+ and 2 Stable conjugated oligomer dications 1 methylpyrrole (DTP) units at the both ends of the π- systems with methoxy substitu- ents at the 3- position of thienyl units and methylthio end- capping group and benzo[2,1- b:3,4- b′]dithiophene (BDT) unit(s) at the central part with sterically de- manding phenyl substituents were synthesized. From DFT calculations and ESR ex- 2+ was reduced periments, it was concluded that the diradical character in 1 in comparison with the radical character of their reference compound 3·+ composed 2+ was considered to have a of one DTP and one BDT units. In addition, the shorter 1 2+. Nevertheless, judging from the re- further lower diradical character than that of 2 2+ showed a comparable π- 2+ and 2 sults of VT- UV- vis- NIR measurements, both 1 dimerization ability at the DTP moiety in dichloromethane solution with 3·+.
关键词： dithienylpyrrole,diradicaloids,conjugated oligomer dications,benzodithiophene,π- Dimerization
更新于2025-09-10 09:29:36