Descripción
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Laser induced forward transfer (LIFT) technique has been previously used for printing metallic contacts onto flexible optoelectronics devices, patterning solder paste for microelectronics or for the metallization of the front side of solar cells. In the latter case, LIFT is capable of making better contacts by improving their aspect ratio while reducing the amount of silver paste wasted. The mechanisms for material transfer using LIFT have been widely discussed in the case of solid and Newtonian fluids. However, the particular rheology and very large viscosity of silver pastes used for metallization of solar cells has led the particular mechanisms and printing results obtained to remain unclear. In this work, a study of LIFT of single dots of a high viscosity silver paste was performed using ns-pulsed lasers. Phenomenological and analytical descriptions are given of the influence of process parameters on the morphology of transferred paste dots characterized by means of confocal microscopy and time-resolved imaging. Four transfer regimes are defined in accordance with the observed distinctive paste dot morphologies on the acceptor: non-dot transfer, in which the pulse energy is below the transfer threshold of a given paste thickness; cluster-dot transfer, where the dot size increases as a function of pulse energy for relatively thin films of paste; concrete-dot transfer, when the paste is thick enough to allow the protruding jet to impact the acceptor substrate without separating from the donor substrate; and explosion-dot transfer, where the high laser pulse energy generates a bursting ejection on the donor that splashes paste on the acceptor. | |
Internacional
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Nombre congreso
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Photonics West 2016 |
Tipo de participación
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960 |
Lugar del congreso
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San Francisco, Estados Unidos |
Revisores
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Si |
ISBN o ISSN
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DOI
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Fecha inicio congreso
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13/02/2016 |
Fecha fin congreso
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18/02/2016 |
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Título de las actas
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No se publica en actas ya que se ha publicado previamente el artículo Applied Surface Science |