The glovebox system facilitates the processing of thin film photovoltaic cells without breaking the inert gas conditions between processing steps. Liquid processing techniques, like spin coating and doctor blading, as well as vacuum based deposition can be used for device preparation. The quality control of the devices by IV-characterization can be done directly after production inside the glovebox system without exposing the devices to air.
Figure 1: Gloveboxsystem with attached vacuum deposition chamber.
Slot-die coating & Laser ablation
A sheet-to-sheet laboratory slot-die coater constitutes the ideal technological bridge between small-area lab-scale thin film preparation techniques such as spin-coating on one hand and large area industrial roll-to-roll processing on the other. Industrial application of slot-die coating is widely used for high-throughput coating of e.g. steel, magnetic-tapes, carpets, and many others up to processing speeds of 1200 m/min (20 m/s). In comparison to other printing and coating techniques, slot-die coating provides superior control of film deposition with high accuracy and laterally homogeneous film thickness.
Unfortunately – and in contrast to printing techniques – slot-die coating does not allow for precise lateral structuring. Therefore a structuring technique has to be applied sequentially to the film deposition. Laser ablation is a technologically advanced high resolution structuring technique, similarly allowing for high-throughput processing of up to several meters per second web speed.
Hence a combination between slot-die coating and laser ablation fulfills all requirements for monolithic solar module production and allows for fast technology transfer “from lab to fab”.
Figure 2: Schematic illustration of a roll-to-roll slot-die coating process. The ink is ejected through a very fine slit. Very thin layers can be applied with fast web speed.
Figure 3: Schematic setup of a laser ablation system. The registration of the laser focus can either be done by a scanner and/or an x-y-stage.
Figure 4: Laser ablation of a single junction thin film monolithic solar module is generally done in three steps: P1 structuring of the semitransparent front contact, P2 structuring of the photoactive layer and P3 structuring of the back contact. See for example .
 R. Rösch, and H. Hoppe, “Module design, fabrication, and characterization”, book chapter in “Organic Solar Cells: Fundamentals, Devices, and Upscaling”, ed. by B. Rand and H. Richter, Pan Stanford Publishing (2014), ISBN 978-981-4463-65-2.