Controlling the Texture and Crystallinity of Evaporated Lead Phthalocyanine Thin Films for Near-Infrared Sensitive Solar Cells

Vasseur, Karolien; Broch, Katharina; Ayzner, Alexander L.; Rand, Barry P.; Cheyns, David; Frank, Christian; Schreiber, Frank; Toney, Michael F.; Froyen, Ludo; Heremans, Paul

doi:10.1021/am401933d

Cited by 54 publications

(62 citation statements)

References 85 publications

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“…The molecular arrangements of polymorphs influence the optical and transport properties of thin films significantly. It has been demonstrated that the absorption spectrum of MPc is red shifted in the triclinic structure due to increased intermolecular interactions in this phase . In order to gain control over the organic thin films phase and morphology, organic molecular beam deposition has been effectively utilized to get good reproducibility.…”

Section: Introductionmentioning

confidence: 99%

Influence of substrate on molecular order for self‐assembled adlayers of CoPc and FePc

Kumar

Naumenko

Cozzarini

et al. 2018

J Raman Spectroscopy

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Self‐assembled metal phthalocyanine thin films are receiving considerable interest due to their potential technological applications. In this study, we present a comprehensive study of CoPc and FePc thin films of about 50 nm thickness on technologically relevant substrates such as SiOx/Si, indium tin oxide (ITO) and polycrystalline gold in order to investigate the substrate induced effects on molecular stacking and crystal structure. Raman spectroscopic analysis reveals lower intensity for the vibrational bands corresponding to phthalocyanine macrocycle for the CoPc and FePc thin films grown on ITO as compared to SiOx/Si due to the higher order of phthalocyanine molecules on SiOx/Si. Atomic force microscopy analysis displays higher grain size for FePc and CoPc thin films on ITO as compared to SiOx/Si and polycrystalline gold indicating towards the influence of molecule–substrate interactions on the molecular stacking. Grazing incidence X‐ray diffraction reciprocal space maps reveal that FePc and CoPc molecules adopt a combination of herringbone and brickstone arrangement on SiOx/Si and polycrystalline gold substrate, which can have significant implications on the optoelectronic properties of the films due to unique molecular stacking.

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Section: Introductionmentioning

confidence: 99%

Influence of substrate on molecular order for self‐assembled adlayers of CoPc and FePc

Kumar

Naumenko

Cozzarini

et al. 2018

J Raman Spectroscopy

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“…[1][2][3][4] As such both inorganic and organic thin fi lms have been employed as structural templating layers to improve device parameters. [5][6][7] Copper (I) iodide (CuI) has shown recent promise as an evaporable templating layer for small molecule photovoltaic applications.…”

Section: Doi: 101002/admi201400540mentioning

confidence: 99%

Structural Templating in a Nonplanar Phthalocyanine Using Single Crystal Copper Iodide

Rochford

Ramadan

Keeble

et al. 2015

Adv Materials Inter

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Preparation of CuI single crystals was undertaken to avoid the limited grain size and random in-plane orientation in previously presented CuI thin fi lms. The crystals exhibited hexagonal or triangular habit from slow growth in saturated acetonitrile solution ( Figure 1 a). This is indicative of expression of threefold or sixfold planar symmetry in the top faces of these crystals suggestive of (111) orientation. For surface analysis by low energy electron diffraction (LEED), crystals were mounted on Ta sample plates and loaded into UHV where diffraction patterns were collected without any surface preparation. LEED showed a hexagonal arrangement of spots consistent with a 1 × 1 (111) pattern with no additional spots at lower energies (Figure 1 b). Additionally, X-ray diffraction (XRD) patterns were recorded (in ambient conditions) after careful alignment to the surface normal of the crystal and only {111} refl ections were observed (Figure 1 c). Atomic force microscopy (AFM) images (collected in ambient air) showed that the top faces were fl at with 60° rotational symmetry in their step edge arrangement ( Figure 2 a, b). The combination of these experimental observations established that the crystals are of high quality and possess large exposed (111) top surfaces.Thin fi lms (50 nm thickness) of VOPc were prepared on these surfaces by evaporation at elevated substrate temperature ( T sub = 155 °C). To determine if growth at this temperature resulted in any changes to the CuI single crystal, a control experiment was performed in which the crystal was annealed for 1 h at growth temperature. The resulting LEED pattern was unchanged suggesting no change in the surface crystal structure ( Figure S1, Supporting Information) in agreement with previous high-temperature structural studies. [ 13 ] The crystal structure and surface morphology of the resultant VOPc fi lms were analyzed using XRD and AFM, respectively. Diffraction patterns ( Figure 3 a) exhibit only a single peak which can be indexed as (132) using the VOPc single crystal structure and is the only feature differentiating the VOPc/CuI pattern from that of the bare CuI (111) crystal. In order to ascertain whether a single orientation of VOPc was present, Rietveld refi nement was undertaken on the VOPc/CuI XRD data. The CuI and VOPc were both fi tted with March-Dollase preferred orientation with a March factor of 0.001 (corresponding to 99.9% orientation) around the CuI (111) and VOPc (132) directions, respectively ( Figure S2, Supporting Information). [ 14,15 ] The lack of any other peaks (even those with higher structure factors) which would be expected from the isotropic VOPc powder pattern confi rms a singly oriented fi lm. The (132) plane of the VOPc structure corresponds to a molecular orientation in which the ligand plane of the molecule is normal to the surface as demonstrated in Figure 3 b.Structural templating is a well-established method to infl uence the morphologies and structures of organic semiconductor thin fi lms and therefore control their ele...

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“…Shuttle cock-type phthalocyanines are groups of semi-conductive materials with Q-band absorption in red to near-infrared wavelength. Non planar phthalocyanine such as titanyl phthalocyanine (TiOPc), lead phthalocyanine (PbPc), and vanadyl phthalocyanine (VOPc) have a variety of crystal structure at phase transition between H-aggregation (phase I) and J-aggregation (phase II) that absorbs at longer wavelength [1][2][3]. They are applied for electronic and optical devices, chemical pigments and photovoltaic application as used for donor materials in organic solar cells [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of inverted organic solar cells using shuttle cock-type metal phthalocyanine and PCBM:P3HT

Suzuki¹,

Furukawa²,

Akiyama³

et al. 2015

AIP Conference Proceedings

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Controlling the Texture and Crystallinity of Evaporated Lead Phthalocyanine Thin Films for Near-Infrared Sensitive Solar Cells

Cited by 54 publications

References 85 publications

Influence of substrate on molecular order for self‐assembled adlayers of CoPc and FePc

Influence of substrate on molecular order for self‐assembled adlayers of CoPc and FePc

Structural Templating in a Nonplanar Phthalocyanine Using Single Crystal Copper Iodide

Fabrication and characterization of inverted organic solar cells using shuttle cock-type metal phthalocyanine and PCBM:P3HT

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