Methods for producing polymer gels, and uses thereof

#The invention pertains to the formation of interconnected network structures in polymer gels created from a semiconducting polymer solution using a novel gelation pathway. The polymer gels can be used in the production of organic solar cells, or to produce polymer nanocomposites with hierarchical porosity in applications such as membrane filtration and food products.

#Organic solar cells are potentially a multi-trillion-dollar product opportunity that could be used world-wide for conversion of solar energy into electricity. Their flexibility would allow them to be installed on curved surfaces, including those of vehicles and buildings, as well as windows due to their semi-transparent nature. These lightweight, portable devices can also be used for electricity generation in off-grid field operations.

#For bulk-heterojunction organic solar cell applications, regioregular poly(3-hexylthiophene) (also described herein as “RR-P3HT”) is usually co-dissolved in solution with phenyl-C61-butyric acid methyl ester (hereinafter also referred to as “PCBM”), which is then spun-cast onto device platforms to form a photoactive layer. Creating organic solar cells in this manner has been expensive due, among other things, to the high-cost of spin coating. Furthermore, lower efficiencies have oftentimes been seen in comparison to inorganic solar cells.

#For a more complete understanding of the present disclosure, reference is made to the following detailed description of an exemplary embodiment considered in conjunction with the accompanying drawings, in which:

#FIG. 1 depicts one embodiment of an apparatus including an extruder adapted for the manufacture of organic solar cells;

#FIG. 2 shows a J-V curve of best performing solar devices manufactured according to an embodiment of the present invention, depicting results achieved with no cooling step and with a cooling step;

#Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

#The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives that fall within the scope of embodiments of the invention.

#Some embodiments of the invention include methods for improvement of the manufacture of organic solar cells. In an embodiment, regioregular poly(3-hexylthiophene) is initially mixed with phenyl-C61 butyric acid methyl ester and one or more solvents, typically ortho-dichlorobenzene (hereinafter also referred to as “o-DCB”), using continuous processing means, such as a twin-screw extruder, to generate a solution of regioregular poly(3-hexylthiophene) and PCBM. The solution is then rapidly cooled to form a gel, and the cooled gelatinous solution is pumped through a doctor blade in order to coat a substrate, typically indium tin oxide. The coating process can be done using the same continuous processing means employed in the mixing, dissolving and cooling steps referenced hereinabove. Subsequently, the solvent can be removed and the structure can be annealed by passing the coated substrate through an environmentally-controlled oven (i.e., an oven controlled for temperature and humidity).