Upscaling of polymer solar cell fabrication using full roll-to-roll processing

Abstract

Upscaling of the manufacture of polymer solar cells is detailed with emphasis on cost analysis and practical approach. The device modules were prepared using both slot-die coating and screen printing the active layers in the form of stripes that were serially connected. The stripe width was varied and the resultant performance analysed. Wider stripes give access to higher geometric fill factors and lower aperture loss while they also present larger sheet resistive losses. An optimum was found through preparation of serially connected stripes having widths of 9, 13 and 18 mm with nominal geometric fill factors (excluding bus bars) of 50, 67 and 75% respectively. In addition modules with lengths of 6, 10, 20, 22.5 and 25 cm were explored. The devices were prepared by full roll-to-roll solution processing in a web width of 305 mm and roll lengths of up to 200 m. The devices were encapsulated with a barrier material in a full roll-to-roll process using standard adhesives giving the devices excellent stability during storage and operation. The total area of processed polymer solar cell was around 60 m2 per run. The solar cells were characterised using a roll-to-roll system comprising a solar simulator and an IV-curve tracer. After characterisation the solar cell modules were cut into sheets using a sheeting machine and contacted using button contacts applied by crimping. Based on this a detailed cost analysis was made showing that it is possible to prepare complete and contacted polymer solar cell modules on this scale at an area cost of 89 euro m(-2) and an electricity cost of 8.1 euro Wp(-1). The cost analysis was separated into the manufacturing cost, materials cost and also the capital investment required for setting up a complete production plant on this scale. Even though the cost in euro Wp(-1) is comparable to the cost for electricity using existing technologies the levelized cost of electricity (LCOE) is expected to be significantly higher than the existing technologies due to the inferior operational lifetime. The presented devices are thus competitive for consumer electronics but ill-suited for on-grid electricity production in their current form.

Roll‐to‐Roll fabrication of large area functional organic materials

“…The first three layers (ZnO, active layer, and PEDOT:PSS) were processed using slot-die coating, and finally a silver back electrode was slot-die coated or flat bed screen printed to finalize the stack before it was laminated. Since then, numerous productions of solar cells and modules based on this method have been published, [20][21][22][23][24][25][26] and solar modules produced according to this have been used in interlaboratory studies, 86,87 round robins, 88,89 and in demonstrators of various kinds that have mostly involved sound, light, or in one case a laser (see Fig. 6).…”

Block copolymer strategies for solar cell technology

“…Ideally, the processing of the active OPV layer needs to be simple and rapid, so that it is compatible with existing rollto-roll (R2R) technology akin to the manufacture of conventional polymer films that have also recently been demonstrated for solar cell blend manufacture. 163,204,205 Conventional routes to deposit thin uniform films on substrates over large areas involve spin coating or doctor blading. The main drawback with these deposition methods is that they do not produce well-ordered block copolymer states (particularly the spin-coating approach) as they are highly nonequilibrium processes where rapid solvent removal quenches the polymer morphology without allowing the system time to reach the lowest energy equilibrium state.…”

Aqueous Processing of Low-Band-Gap Polymer Solar Cells Using Roll-to-Roll Methods

“…The devices were finally encapsulated using a simple barrier foil as described earlier and tested using an automated roll-to-roll IV-tester. 8,14,15 Morphology. The morphology differences between spin-coated and R2R prepared samples and between the different sample materials can clearly be observed in the AFM images in Figure 6.…”