DOI: 10.1002/aenm.201401539 materials than are commonly used in research labs. We have used an industrial printer to produce BHJ solar cells [ 12 ] and found that over 30 L of ink was required to start roll-to-roll production. On a smaller scale, an industrial proofer, which is used to mimic printing conditions in a roll-to-roll production line, still consumed a lot of ink, with 100 mL of ink and 3 g of polymer typically used in a single set of experiments. [ 12 ] Even a small, laboratory scale, roll-to-roll printer typically requires a few tens of milliliters of ink. Although most of the ink used to fi ll the reservoir can often be recovered, the amount of material required to test various formulations is far more than typically available for newly synthesized materials. Therefore, very few results for fully printed solar cells have been reported with high performance materials. The convergence of BHJ, DSSC, and perovskite device structures provides the fi eld with an opportunity to now focus on the “lab-to-fab” translation of these solar cell technologies. To do this, ready access to a coating process that enables the solution-based deposition of multiple layers is required. In the general area of rapid prototyping, 3D printing has emerged as a powerful tool for the low-cost, rapid production of industrial products or prototypes. [ 13 ] 3D Printing is an example of additive manufacturing that builds a device from a surface, directly from a design meaning that a computer-aided design (CAD) fi le can be transformed to a fi nished product without additional cutting or assembling steps. Among the many types of 3D printers that are available, the fused deposition modeling (FDM) type printer has been developed rapidly and is becoming more and more popular as it becomes more affordable. FDM 3D printers have been developed to produce objects by printing multiple thick layers (typically over 100 μm) of melted plastic but can also be used to produce thin, solid fi lms. FDM 3D printers are technically an automated extruder with x, y, z position control and typically can vary head speed/acceleration/ deceleration as well as the temperature of the nozzles and a printing bed. Resources to build and control FDM 3D printers have been developed and shared by an open source community. [ 14 ] We therefore recognized that such a printer could be used as a comprehensive research tool kit if converted to allow processing of solutions instead of solid fi laments. Furthermore, we also recognized that 3D printers have a number of other advantages over conventional printers/coaters. As a 3D printer is controlled by digital code, no hardware change is required to vary the printing pattern, allowing different device structures or designs to be tested without preparing new masks, forms, or other physical patterning. The digital instruction protocol, G code, is a machine-independent standard which means that optimized printing conditions can be transferred from machine Solution-processed solar cells continue to show great promise as a disruptive energy generation technology due to their inherently low manufacturing costs and increasing effi ciencies. [ 1–3 ]
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Dec 1, 2016
Sang Hyun Ahn + 3
