Investigations on knife and slot die coating and processing of polymer nanoparticle films for hybrid polymer solar cells

Wengeler, L.; Schmidt‐Hansberg, Benjamin; Peters, K.; Scharfer, Philip; Schabel, Wilhelm

doi:10.1016/j.cep.2010.11.002

Cited by 42 publications

(15 citation statements)

References 33 publications

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“…In order to have an impact on the power generation market on the longer term, organic photovoltaics should combine high power conversion efficiency with low production costs and long term stability. The low cost potential is based on the use of low‐cost materials and substrates and the very high production speeds that can be reached by roll‐to‐roll printing and coating 1–13. The presence of a transparent conducting electrode such as indium tin oxide (ITO) limits the reliability and significantly increases the cost of organic photovoltaic devices as it is brittle and expensive 13–17.…”

Section: Introductionmentioning

confidence: 99%

Current Collecting Grids for ITO‐Free Solar Cells

Galagan

Zimmermann

Coenen³

et al. 2011

Advanced Energy Materials

119

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Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front electrode comprising silver grid lines and a semitransparent PEDOT:PSS conductor are demonstrated. The effect of grid line density is explored for a large series of devices and a careful modeling study enabling the identification of the most rational grid structure is presented. Both optical and light beam induced current (LBIC) mapping of the devices are used to support the power loss model and to follow the evolution of the performance over time. Current generation is found to be evenly distributed over the active area initially progressing to a larger graduation in areas with different performance. Over time coating defects also become much more apparent in the LBIC images. Results and DiscussionA series of large area (2 cm × 2 cm) ITO-free organic solar cell devices were prepared on glass substrates (Figure 1). The devices contained current collecting grids/high conductivity PEDOT:PSS/P3HT:PCBM/LiF:Al. A schematic illustration of the devices is shown in Figure 1a. Current collecting grids are represented as parallel lines with different spacing (pitch size) ( Figure 1b). The devices with pitch sizes of 20, 10, 6.7, 5, 3.3, 2.5, 2, and 1 mm were prepared. The pitch size is defined as the distance between the centers of two neighboring grid lines. The number of the grid lines in the devices was changed as 1, 2, 3, 4, 6, 8, 10, and 20, respectively. The width of the grid lines was constant for each batch of devices. Thus shadowing losses increase with the number of grid lines. The effect of different pitch for the grid fingers was calculated at Fraunhofer ISE using a one dimensional numerical model developed by Glatthaar et al. [37,38] Each infinitesimal cell element with width dx delivers the current j(V(x))dx. The function j(V) is given by the current-voltage (JV)-curve of a small area device. Starting from x = 0 the current sums up to I(x) (Equation 1). This current leads to a voltage drop in the current collecting electrode corresponding to Ohm´s law (Equation 2), with ρ being the sheet resistance of the electrode(s). As the current output from the infinitesimal cell elements depends on the voltage V(x) at position x, also the current density j(V(x)) depends on the position x. Therefore the two differential Equations 1 and 2 are coupled:with the boundary conditions V (x = 0) = V 0 and I(x = 0) = 0.The area loss, which in a one dimensional model is the length l loss due to coverage with grid fingers or dead area due to series circuitry is accounted for by integrating the current I from 0 to the length of the active area l active but normalizing the current to the length including the lost "area" l active + l loss . The JV curve of the grid cell or module respectively therefore is given by:The model was used to consecutively calculate the ohmic and area losses in the PEDOT layer and metal fingers. The procedure was to first calculate the loss due to the distributed PEDOT resistance and only the shadow loss induced...

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Section: Introductionmentioning

confidence: 99%

Current Collecting Grids for ITO‐Free Solar Cells

Galagan

Zimmermann

Coenen³

et al. 2011

Advanced Energy Materials

119

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“…The substrate spins until the composite dries up, and the final thickness is controlled by the frequency of the spin, composition and properties of the material as well as the drying conditions. Spin-coating parameters are interdependent on each other; for example, an increase in spin frequency results in a lower film thickness, higher drying rate and higher shear rate [123]. Nagata et al [124] used spin coating to prepare a BHJ OSC with coplanar interdigitized electrodes.…”

Section: Spin Coating Methodsmentioning

confidence: 99%

A review on carbon nanotube/polymer composites for organic solar cells

Keru

Ndungu

Nyamori

2014

Int. J. Energy Res.

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SUMMARY Carbon nanotubes (CNTs) have unique properties, such as their electrical conductivity, that enable them to be combined with conducting polymers to form composites for use in organic solar cells (OSCs). It is envisaged that the improved composite has a higher efficiency of green energy and will reduce the cost of these cells. The use of such alternative energy sources also drastically reduces overuse of fossil fuels and consequently limits environmental degradation. This review compares research and performance between conventional silicon solar cells and OSCs. It also discusses OSC photoexcitation and charge carrier generation with the incorporation of CNTs, physicochemical properties of the composites and other factors that affect the efficiencies of OSCs. In addition, properties of CNTs that favour their dispersion in polymer matrices as acceptors and charge carriers to the electrodes are covered. The effects of CNTs containing dopants, such as nitrogen and boron, on charge transfer are discussed. Also, the fabrication techniques of OSCs that include CNT/polymer composite processing and the methods of film deposition on the substrate are described. Finally, the case studies of OSCs containing polymers with single‐walled CNTs, double‐walled CNTs or multi‐walled CNTs are evaluated. Copyright © 2014 John Wiley & Sons, Ltd.

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“…Roll-to-roll (R2R) technique is widely used in the industries, which is capable of producing large-scale devices and it can be operated in a normal environment. This R2R device fabrication technique is normally used to fabricate polymer based organic electronic devices [14][15][16]. According the best of our knowledge, fabrication of SM-OPV by roll-to-roll coating has not been fulfilled.…”

Section: Introductionmentioning

confidence: 98%