Does Electronic Type Matter when Single‐Walled Carbon Nanotubes are Used for Electrode Applications?

Abstract

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Single-walled carbon nanotube (SWNT) electrodes that are chemically and mechanically robust are fabricated using a simple drop cast method with thermal annealing and acid treatment. An electronic-type selective decrease in sheet resistance of SWNT electrodes with HNO<inf>3</inf> treatment is shown. Semiconducting SWNTs show a significantly higher affinity toward hole doping in comparison to metallic SWNTs; a ≈12-fold and a ≈fivefold drop in sheet resistance, respectively. The results suggest the insignificance of the electronic type of the SWNTs for the film conductivity after hole doping. The SWNT films have been employed as transparent hole extracting electrodes in bulk heterojunction (BHJ) organic photovoltaics. Performances of the devices enlighten the fact that the electrode film morphology dominates over the electronic type of the doped SWNTs with similar sheet resistance and optical transmission. The power conversion efficiency (PCE) of 4.4% for the best performing device is the best carbon nanotube transparent electrode incorporated large area BHJ solar cell reported to date. This PCE is 90% in terms of PCEs achieved using indium tin oxide (ITO) based reference devices with identical film fabrication parameters indicating the potential of the SWNT electrodes as an ITO replacement toward realization of all carbon solar cells. Fabrication of electronic-type separated single-walled carbon nanotube (SWNT) electrodes for organic solar cells, using a simple drop cast method followed by thermal and acid treatment. The thermal and acid treatment processes significantly enhance the conductivity of the SWNT films, enabling the use of the conductivity-enhanced SWNT layers as hole extracting, transparent electrodes in organic bulk heterojunction solar cells

Organic Optoelectronic Materials: Mechanisms and Applications

“…Cost-effective solutions for the ITO replacement have been actively sought after as well, using other oxides (e.g., FTO or AZO), CNTs, 1168 metal mesh or nanowires, 1169−1173 and other materials. 1174,1175 For example, Kim et al 1169 ature roll-to-roll sputtering.…”

“…Cost-effective solutions for the ITO replacement have been actively sought after as well, using other oxides (e.g., FTO or AZO), CNTs, metal mesh or nanowires, − and other materials. , For example, Kim et al reported a Cu 2 O/Cu/Cu 2 O multilayer mesh electrode grown by room-temperature roll-to-roll sputtering. They demonstrated a low sheet resistance of ∼15 Ohm/square, high optical transmittance of ∼89%, and good mechanical flexibility.…”

Graphene and Graphene-like Molecules: Prospects in Solar Cells

“…Numerous reports have shown that stand-alone CNTs can act as good electrodes in solar cells, with efficiency ranging from 4.4% to 6.32% (Table ). − A hybrid graphene/CNT electrode has lower charge-transfer resistance with the electrolyte (20 times smaller than for platinum-based cathodes) owing to its large surface area. DSSCs utilizing this flexible, vertically aligned CNT/graphene hybrid cathode out­performed Pt-based cells in both rigid (8.2% vs 6.4%) and flexible (3.9% vs 3.4%) assemblies.…”

Application of quinoline derivatives in third-generation photovoltaics

“…These materials are frequently treated and modified [43][44][45][46][47][48]. Other common electrode materials are tungsten oxide [49][50][51] or materials based on graphene [52,53] and nanotubes [54][55][56]. The second electrode is usually made of metal [57][58][59].…”