Solubilization of Carbon Nanotubes with Ethylene-Vinyl Acetate for Solution-Processed Conductive Films and Charge Extraction Layers in Perovskite Solar Cells

Abstract

Carbon nanotube (CNT) solubilization via non-covalent wrapping of conjugated semiconducting polymers is a common technique used to produce stable dispersions for depositing CNTs from solution. Here, we report the use of a non-conjugated insulating polymer, ethylenevinyl acetate (EVA), to disperse multi-and single-walled CNTs (MWCNT and SWCNT) in organic solvents. We demonstrate that despite the insulating nature of the EVA, we can produce semi-transparent films with conductivities of up to 34 S/cm. We show, using photoluminescence spectroscopy, that the EVA strongly binds to individual CNTs thus making them soluble, preventing aggregation, and facilitating the deposition of high quality films. To prove the good electronic properties of this composite, we have fabricated perovskite solar cells using 2 EVA/SWCNT and EVA/MWCNTs as selective hole contact, obtaining power conversion efficiencies of up to 17.1%, demonstrating that the insulating polymer does not prevent the charge transfer from the active material to the CNTs.

Light-Stable Methylammonium-Free Inverted Flexible Perovskite Solar Modules on PET Exceeding 10.5% on a 15.7 cm2 Active Area

“…The perovskite layer was optimized starting from a standard double-cation recipe found in the literature. 61 We changed the solvent system from a standard N , N -dimethylformamide/dimethyl sulfoxide (DMF/DMSO) 4:1 volume ratio used mainly for the spin-coating process to N -methyl-2-pyrrolidone (NMP)/DMF 95:5 already optimized for the blade-coating process in a previous report. 62 The study on the concentration was carried out using 1.45, 1.6, 1.8, and 2 M concentrations.…”

Organic Solar Cells—The Path to Commercial Success

“…The challenge for alternative electrode materials is to achieve high transparency in the solar spectrum, high conductivity, mechanical and environmental stability as well as only use abundant materials and be compatible with low-cost, large-scale production on metals and plastic foils. [79] The most promising approaches to replace ITO are increasing the conductivity of organic semiconductors, in particular PEDOT:PSS, [80] metallic nanowires, [81,82] carbon nanotubes, [83,84] and thin metal layers. [85,86] In case the lateral conductivity needs to be boosted further, these layers can be supported with metal grids.…”

Development of a Screen-Printable Carbon Paste to Achieve Washable Conductive Textiles

“…Previously, EVA has been applied in flexible electrical devices, such as spray-coated conductive films for solar cell electrodes [32], spin-coated transparent electrodes [33], screen-printed conductors for paper-based electronics [34], and a dip-coated conductive membrane for energy storage [35]. This environmentally friendly copolymer is also widely used in food packaging, as an encapsulation material for flexible photovoltaic devices [36], as a hot-melt adhesive [37], and as a flexible adhesive layer between textile insole pads [38].…”