Photovoltaic properties of octithiophene-based Schottky and p/n junction cells: Influence of molecular orientation

Videlot, C.; Kassmi, A. El; Fichou, Denis

doi:10.1016/s0927-0248(00)00021-0

Cited by 87 publications

(38 citation statements)

References 18 publications

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“…A blue shift of λ max was observed for the vertically oriented molecules. No PV effect was observed in this case while a small PCE was observed for the horizontally oriented molecules …”

Section: Molecular Donors Based On Low Molecular Weight Chromophoresmentioning

confidence: 66%

Molecular Materials for Organic Photovoltaics: Small is Beautiful

2014

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An overview of some recent developments of the chemistry of molecular donor materials for organic photovoltaics (OPV) is presented. Although molecular materials have been used for the fabrication of OPV cells from the very beginning of the field, the design of molecular donors specifically designed for OPV is a relatively recent research area. In the past few years, molecular donors have been used in both vacuum-deposited and solution-processed OPV cells and both fields have witnessed impressive progress with power conversion efficiencies crossing the symbolic limit of 10 %. However, this progress has been achieved at the price of an increasing complexity of the chemistry of active materials and of the technology of device fabrication. This evolution probably inherent to the progress of research is difficult to reconcile with the necessity for OPV to demonstrate a decisive economic advantage over existing silicon technology. In this short review various classes of molecular donors are discussed with the aim of defining possible basic molecular structures that can combine structural simplicity, low molecular weight, synthetic accessibility, scalability and that can represent possible starting points for the development of simple and cost-effective OPV materials.

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“…A blue shift of λ max was observed for the vertically oriented molecules. No PV effect was observed in this case while a small PCE was observed for the horizontally oriented molecules …”

Section: Molecular Donors Based On Low Molecular Weight Chromophoresmentioning

confidence: 66%

Molecular Materials for Organic Photovoltaics: Small is Beautiful

2014

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“…1). [10,11] While processable conjugated polymers such as P3HT could be a priori viewed as isotropic materials, it has been shown that the charge-transport process in thin films is in fact 2D, with a highest in-plane mobility in the crystallized zones of the polymer when chains are oriented edge-on on the substrate (Fig. 1).…”

Section: Organic Semiconductors Based On P-conjugated Systems Are Thementioning

confidence: 99%

From One‐ to Three‐Dimensional Organic Semiconductors: In Search of the Organic Silicon?

2007

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Organic semiconductors based on π‐conjugated systems are the focus of considerable interest in the emerging area of soft or flexible photonics and electronics. Whereas in recent years the performances of devices such as organic light‐emitting diodes (OLEDs), organic field‐effect transistors (OFETs), or solar cells have undergone considerable progress, a number of technical and fundamental problems related to the low dimensionality of organic semiconductors based on linear π‐conjugated systems remain unsatisfactorily resolved. This low dimensionality results in an anisotropy of the optical and charge‐transport properties, which in turn implies a control of the material organization/molecular orientation during or after device fabrication. Such a constraint evidently represents a problem when device fabrication by solution‐based processes, such as printing techniques, is envisioned. The aim of this short Review is to illustrate possible alternative strategies based on the development of organic semiconductors with higher dimensionality, capable to exhibit isotropic electronic properties.

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“…Therefore, organic thin film transistors have benefitted from achieving vertical molecular alignment with molecules standing up, or edge‐on, such that the π‐π stacking direction is parallel to the substrate as well as the conducting channel 6. Furthermore, optical properties such as absorption and emission are most often anisotropic, a characteristic which has been exploited for both organic light emitting diodes7 as well as for organic solar cells 8. Finally, one should not neglect the change in energy levels that can be associated with a change in orientation of a thin film, and which can have an effect on heterojunction processes 9…”

Section: Introductionmentioning

confidence: 99%

The Impact of Molecular Orientation on the Photovoltaic Properties of a Phthalocyanine/Fullerene Heterojunction

Rand

Cheyns

Vasseur

et al. 2012

Adv Funct Materials

306

312

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The anisotropy inherent to many planar organic molecules leads to a high sensitivity of various fundamental processes to the orientation of molecules within fi lms and at heterojunctions. Such processes include absorption, charge and exciton transport, energy levels, and charge transfer, all of which are critical to organic solar cell operation. Here,an in-depth study of bilayer cells consisting of a donor/acceptor interface between zinc phthalocyanine (ZnPc) and fullerene (C 60 ) is conducted and devices with the typically deposited standing up (edge-on) orientation are compared to those with ZnPc lying fl at (face-on). The face-on ZnPc-based device allows for an increase in all solar cell parameters, substantially increasing power conversion effi ciency from 1.5% to 2.8%. Spectrally resolved photocurrent measurements reveal a > 50% increase in ZnPc signal, from which only 12% is accounted for by the increase in absorption associated with the face-on orientation. The increase in internal quantum effi ciency is accounted for via an improved charge transfer. The results of this study indicate that proper consideration of the orientation between donor and acceptor needs to be taken in order to fully optimize the numerous processes required for photovoltaic energy conversion.

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Photovoltaic properties of octithiophene-based Schottky and p/n junction cells: Influence of molecular orientation

Cited by 87 publications

References 18 publications

Molecular Materials for Organic Photovoltaics: Small is Beautiful

Molecular Materials for Organic Photovoltaics: Small is Beautiful

From One‐ to Three‐Dimensional Organic Semiconductors: In Search of the Organic Silicon?

The Impact of Molecular Orientation on the Photovoltaic Properties of a Phthalocyanine/Fullerene Heterojunction

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