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4.2 polymer interaction with znpcs functionalized zinc oxide 53Figure 4.4.: Building of a layer of ZnPcs on the ZnO surface startingfrom a single relaxed molecule.4.2 polymer interaction with znpcs functionalizedzinc oxideOnce the ZnO surface fully covered by ZnPcs is obtained,the further step is to investigate the interaction with a singlepolymer molecule. We want to study how the ZnPcsaffects the interaction with the substrate. For this purposewe used a oligomer composed by 8 thiophenes (see Figure4.5 left). We investigated the interaction between thepolymer and the ZnO/ZnPcs surface by calculating the attractionbasin reported in Figure 4.5 top right, where theenergy is calculated as a function of the relative distancebetween the polymer and the surface.At each distance from the substrate the energy was minimizedwith respect to different orientations of the molecule.The calculated energy curve exhibits a minimum for polymersubstratedistance of about 3 Å and an interaction rangeof about 1 nm. By fully optimizing the minimum energyconfiguration we obtain the lowest energy structure of the
54 ternary zno/znpc/p3ht systemP3HT/ZnPc/ZnO interface in which the polymer lies alongthe 〈010〉 direction above a ZnPcs stripe (see Figure 4.5).By annealing the system for 1 ns the interface is preserved,with the ZnPcs interlayer still between the polymer andthe metaloxide and no diffusion of the polymer on the Zn-Pcs is observed. This is consistent with the strong bindingof the ZnPc with ZnO that is larger than the P3HT/ZnOinteraction.Furthermore, the calculated value for the P3HT/ZnPcsinteraction is comparable to the P3HT/ZnO (0.7 eV/thiophene)and much larger than the P3HT/P3HT interaction(0.1 eV/thiophene[3]). This suggests that the parallel geometryof the polymer is favored with respect to other polymerorganizations at the interface, similar in the case ofP3HT on the ZnO bare surface.Figure 4.5.: Attraction basin between the ZnO/ZnPcs interface andthe P3HT oligomer and final configuration of the ternarysystem after the relaxation.
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Università degli Studi di Cagliari
Page 4:
A C K N O W L E D G M E N T SI woul
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example of a novel class of systems
Page 10 and 11:
C O N T E N T S1 introduction 11.1
Page 12 and 13:
L I S T O F F I G U R E SFigure 1.1
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List of FiguresxiiiFigure 2.15 Init
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List of FiguresxvFigure 4.6Figure 4
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Figure 5.7Figure 5.8Figure A.1Figur
Page 21 and 22: 2 introduction1-3 eV) and the trans
Page 23 and 24: 4 introductionorder in such a compl
Page 25 and 26: 6 introductionprocesses that need t
Page 27 and 28: 8 introduction1.2 physical factors
Page 29 and 30: 10 introductionrecovered by the int
Page 31 and 32: 12 introductionA cheap and environm
Page 33 and 34: 14 introductiondensed phases [63, 7
Page 36 and 37: P 3 H T - P O LY ( 3 - H E X Y LT H
Page 38 and 39: 2.1 mechanism of assembling and mor
Page 40 and 41: 2.2 p3ht assembling and intermolecu
Page 42 and 43: 2.3 p3ht crystalline bulk phases 23
Page 44 and 45: 2.5 nanocrystalline p3ht 25Figure 2
Page 46 and 47: 2.5 nanocrystalline p3ht 27Table 2.
Page 48 and 49: 2.6 conclusions 29Figure 2.13.: Ini
Page 50 and 51: P O LY M E R / S E M I C O N D U C
Page 52 and 53: 3.3 adhesion of a single p3ht molec
Page 54 and 55: 3.4 p3ht/zno interface 35surface (t
Page 56 and 57: 3.5 p3ht/zno interface: low deposit
Page 58 and 59: 3.6 p3ht/zno interface: high deposi
Page 64 and 65: 3.7 effective model for the transpo
Page 66 and 67: 3.8 conclusions 47As for the low te
Page 68 and 69: T E R N A RY Z N O / Z N P C / P 3
Page 70 and 71: 4.1 self assembling of znpcs on zno
Page 74 and 75: 4.3 electronic and optical properti
Page 76 and 77: 4.3 electronic and optical properti
Page 78 and 79: 4.4 conclusions 59ties. The absorpt
Page 80 and 81: I N T E R A C T I O N B E T W E E N
Page 82 and 83: 5.2 solvent thf interaction with zn
Page 88 and 89: 5.3 conclusions 69γ L/L ∼ 0.112
Page 90 and 91: C O N C L U S I O N SIn this thesis
Page 92 and 93: M O L E C U L A R D Y N A M I C SAa
Page 94 and 95: A.1 molecular dynamics 75a.1.2The t
Page 96 and 97: A.2 the force field 77Finally, τ t
Page 98 and 99: A.2 the force field 79Waals interac
Page 100 and 101: A.3 methods 81tional Theory (DFT) l
Page 102 and 103: B I B L I O G R A P H Y[1] http://w
Page 104 and 105: ibliography 85[17] J. D. Servaites,
Page 106 and 107: ibliography 87Zakeeruddin, and M. G
Page 108 and 109: ibliography 89Phys. Chem. Chem. Phy
Page 110 and 111: ibliography 91[65] D. J. Binks and
Page 112 and 113: ibliography 93cells,” Energy Envi
Page 114 and 115: ibliography 95[97] C. Ingrosso, A.
Page 116 and 117: ibliography 97298.15 k,” Journal
Page 118 and 119: ibliography 99charges. am1-bcc mode
Page 120: colophonThis document was typeset u
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