Low-Cost and Green Fabrication of Polymer Electronic Devices by Push-Coating of the Polymer Active Layers

Abstract

Because of both its easy processability and compatibility with roll-to-roll processes, polymer electronics is considered to be the most promising technology for the future generation of low-cost electronic devices such as light-emitting diodes and solar cells. However, the state-of-the-art deposition technique for polymer electronics (spin-coating) generates a high volume of chlorinated solution wastes during the active layer fabrication. Here, we demonstrate that devices with similar or higher performances can be manufactured using the push-coating technique in which a poly(dimethylsiloxane) (PDMS) layer is simply laid over a very small amount of solution (less than 1μL/covered cm), which is then left for drying. Using mm thick PDMS provides a means to control the solvent diffusion kinetics (sorption/retention) and removes the necessity for additional applied pressure to generate the desired active layer thickness. Unlike spin-coating, push-coating is a slow drying process that induces a higher degree of crystallinity in the polymer thin film without the necessity for a post-annealing step. The polymer light-emitting diodes and solar cells prepared by push-coating exhibit slightly higher performances with respect to the reference spin-coated devices, whereas at the same time reduce the amounts of active layer materials and chlorinated solvents by 50 and 20 times, respectively. These increased performances can be correlated to the higher polymer crystallinities obtained without applying a post-annealing treatment. As push-coating is a roll-to-roll compatible method, the results presented here open the path to low-cost and eco-friendly fabrication of a wide range of emerging devices based on conjugated polymer materials.

Can Polymer Solar Cells Open the Path to Sustainable and Efficient Photovoltaic Windows Fabrication?

“…In fact, even when additional weight was placed on top of the PDMS film to ensure that flat PTB7 : PC 71 BM active layers are produced, the PCE of these push‐coated PSCs only reached values of 2.65 %. We demonstrated that efficient PSCs and OLEDs as well as nanopixel OLEDs can be fabricated by push‐coating with thick PDMS films . In fact, Ikawa et al .…”

“…Despite the fact that slot‐die coating and blade‐coating have similar film formation kinetics, PSCs fabricated by blade‐coating generally exhibit higher performances compared to slot‐die coated ones . Recently, unconventional techniques such as electrospray deposition and push‐coating have demonstrated their potential for high performance device fabrication . Here, I will compare the methods that yield relatively high PCEs, namely, spin‐coating, blade‐coating, electrospray deposition and push‐coating, in terms of cost reduction, environment‐friendliness and sustainability (Figure ).…”

“… Schematic representations of the processes compared in this paper, namely, spin‐coating, blade‐coating, electrospray deposition and push‐coating. Adapted with permissions from, Copyrights 2016, Royal Society of Chemistry; 2010, Wiley‐VCH; 2017, American Chemical Society.…”

“…[35,[72][73][74][75] Recently, unconventional techniques such as electrospray deposition and push-coating have demonstrated their potential for high performance device fabrication. [76][77][78][79][80][81][82] Here, I will compare the methods that yield relatively high PCEs, namely, spin-coating, blade-coating, electrospray deposition and pushcoating, in terms of cost reduction, environment-friendliness and sustainability ( Figure 9).…”

Polarized Emission from Conjugated Polymer Chains Aligned by Epitaxial Growth during Off-Center Spin-Coating

“…In as-spun films of F8BT or MEH-PPV, the degree of order achieved is insufficient to assess a real detectable effect by XRD ( Figure 5) [15][16][17]. As previously demonstrated, a higher degree of order may be obtained by annealing these films at high temperature [17].…”