Stille Polycondensation for Synthesis of Functional Materials

Department of Chemistry and the James Franck Institute, the University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA.
Chemical Reviews (Impact Factor: 45.66). 02/2011; 111(3):1493-528. DOI: 10.1021/cr100320w
Source: PubMed
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    ABSTRACT: Bulk heterojunction (BHJ) polymer solar cells (PSCs) are a popular research subject currently pursued by many groups around the world. The state-of-the-art PSCs are composed of a polymer donor and a fullerene acceptor as the active layer, and their overall photovoltaic performance is dependent on many factors, such as the electrical and optical properties of donor polymers, device architectures, and interfacial layers used. Among them, the nature of donor polymer is without doubt one of the determining factors in performance of PSCs. In this work, we report for the first time the study of the influence of polymer dispersity (Đ) on the performance of PSCs composed of PTB7 and PC71BM as the active layer materials. It was found that polymers exhibiting large Đ contained structural defects that played the role of energy transfer and charge trapping/recombination centers. The power conversion efficiency of PTB7 devices decreased from 7.59% to 2.55% with increased Đ. The results highlighted the importance of controlling Đ of donor polymers for PSCs.
    Chemistry of Materials 01/2015; 27(2):537-543. DOI:10.1021/cm5042953 · 8.54 Impact Factor
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    ABSTRACT: Cavitation is defined as sequential formation, growth and rapid collapse of micro-bubbles or cavities in liquid medium with releasing large amount of energy within small time interval (in few micro seconds). On the Basis of mode of generation, there are four types of cavitation: Hydrodynamic cavitation, Acoustic cavitation, Optic cavitation and Particle cavitation. Hydrodynamic and Acoustic cavitation occur as the result of tension prevailing in liquid while Optic and Particle cavitation occur as the result of local deposition of energy in liquid. Hydrodynamic cavitation has a great scope of scale-up on an industrial scale due to its ability in generating cavitation at a much larger scale than acoustic cavitation. To study the flow characteristics inside a Hydrodynamic cavitating device, computational fluid dynamics (CFD) software is used to simulate flow phenomena in various cavitating devices. This paper reports optimization of various geometrical parameter of different hydrodynamic cavitating reactor such as Slit, Circular and elliptical venturi. Different operating and geometrical parameter such as divergence angle (5.50, 6.50, 7.50), slit height/diameter to length ratio (1:1, 1:2, 1:3) and operating inlet pressure to the cavitating device (2, 4, 6, 8, 10 atm) were selected to study the inception, growth and dynamic of cavitation. Cavitational model and Turbulence model is used to study the CFD of cavitation reactor. In present work, the study of different geometries of venturi (like slit, circular and elliptical) shows that venturi with slit height/diameter to length ratio 1:1 and divergence angle 5.50 is an optimum geometry for best cavitational activity.
    3rd International Conference on “Energy Technology, Power Engineering & Environmental Sustainability”, Jawaharlal Nehru University, New Delhi; 10/2014
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    ABSTRACT: Donor–acceptor conjugated polymers with 2-(2-ethylhexyl)-3-hexyl thienyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDT) as donor building block and 5,6-difluorobenzo[c][1,2,5]thiadiazole as acceptor building block have been synthesized by Stille coupling polymerization. The polymerization conditions were optimized to achieve high molecular weight polymers (number-average molecular weight, Mn, up to 139 kg mol−1). The molecular weight dependent polymer properties were studied and compared. Photovoltaic applications of the polymers in bulk heterojunction (BHJ) solar cells revealed that the power conversion efficiency increased significantly (from 0.9% to 4.1%) as the Mn increased from 10 kg mol−1 to 73 kg mol−1 while further increase of the molecular weight had less influence on the solar cell performance.
    02/2015; 6(12). DOI:10.1039/C4PY01631A


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