AsianScientist (May 7, 2015) – In a study published in Applied Physics Letters, scientists demonstrated an inject printing method to control the patterning of silver nanowires (Ag NW).
Solution-processed Ag NW networks are widely used as transparent or stretchable conductors in touch screens, solar cells, displays, heaters, sensors and other electronics. However, most of the reported conductive Ag NW networks were deposited without patterns, requiring additional patterning procedures such as etching for practical applications.
Although potentially simpler and cheaper, printing Ag NW directly to form conductive patterns is difficult due to the unique dispersion properties of the metal nanowires. Currently, most organic photovoltaic (OPV) devices make use of a network of Ag NW with organic layers deposited on top of it. Only a few groups have attempted to use Ag NW as top electrode in OPV through lamination, spray, or drop-casting approaches, none of which researched the solvent effect to the underlying layers.
In the present study, a team led by Professor Cui Zheng from Printable Electronics Research Center, Suzhou Institute of Nano-Tech and Nano-Bionics, developed conductive Ag NW networks pattern by inkjet printing. They then inkjet printed Ag NW directly as top electrode for semi-transparent organic photovoltaic (OPV) devices by collaborating with a group led by Professor Ma Changqi.
The researchers obtained Ag NW patterns with different sheet resistance and transparency by adjusting inkjet printing parameters. The highest power conversion efficiency (PCE) of OPV device using transparent printed Ag NW as top electrode was achieved to be about 90 percent of the reference device’s PCE, which was fabricated using thermal deposited Ag opaque electrode.
On the other hand, a series of different OPV devices were designed and their current density-voltage (J-V) curves were studied carefully by comparing fabricating process. The results revealed that solvent treatment on the underlying layer during printing led to a decrease of charge injection selectivity and an increase of charge recombination at the anode interface, which was considered to be the reason for the degrading of device performance.
The article can be found at: Lu et al. (2015) Inkjet Printed Silver Nanowire Network As Top Electrode For Semi-transparent Organic Photovoltaic Devices .
Source: Chinese Academy of Sciences.
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