Comparing the Fundamental Physics and Device Performance of Transparent, Conductive Nanostructured Networks with Conventional Transparent Conducting Oxides

Abstract

Networks made of single-walled carbon nanotubes (SWNTs) and metallic nanowire networks, graphene, and ultra-thin metal films have all been proposed as replacements for transparent conducting oxides (TCOs) in photovoltaic and other applications. However, only limited comparisons of nanostructured networks and TCOs are available. Several common figures of merit that are often used to compare the electrical and optical performance of the transparent contacts are evaluated here, and the merits of each method of comparison are discussed. Calculating the current loss due to absorption in the TCO is the most useful metric for evaluating new materials for use in solar cells with well-defined sheet resistance requirements and known quantum efficiencies. The 'Haacke' figure of merit, Φ H , correlates fairly well with current loss and is a good metric for evaluating electro-optical performance for more general applications. The analyses presented here demonstrate that silver nanowire networks are much closer to achieving optimal electrical and optical properties than carbon-based networks.

Flexible transparent conductive materials based on silver nanowire networks: a review

“…Another dependency should be considered for the high-transparency regime where deviation from bulk-like behaviour is observed and can be explained by percolation effects as revealed by the good fit between the dashed lines Reprinted with permission from [118]. (b) Optical transmittance (at 550 nm) versus sheet resistance for graphene [14][15][16][17][18][19], carbon nanotubes [11,[20][21][22][23][24][25][26], AgNWs [27][28][29][30][31][32][33] and ITO [9,11,13]. Solid lines exhibit iso-values of the figure of merit (see text for explanations).…”

Transparent Electrodes for Efficient Optoelectronics

“…For our comparison, we use representative absorptance and R sh data of Ag NWs taken from the current literature. [8,95,159,160] However, we note that intensive research efforts are ongoing on Ag NWs, promising further performance improvements. Such improvements will mainly be achieved by increased fabrication control and deposition of metal grids with submicron-width lines, [161] development of hybrid approaches to improve stability under corrosive and oxidation conditions, as well as improved adhesion to the substrates.…”

“…The properties of Ag NWs, CNTs, and several other nanostructures for applications as transparent electrodes, optimization approaches and performance have been extensively reviewed in ref. [8,89,95] In relation to metallic networks, it is important to mention other recently proposed approaches. One consists of the formation of transparent conductive grid patterns by self-assembly of Ag nanoparticles deposited by ink-jet printing.…”

“…2017, 1600529 www.advancedsciencenews.com Figure 2. a) AM1.5G 1 sun irradiance spectra and b) quantum efficiency of a perovskite, [108] CdTe, [95] CIGS, [95] perovskite-SHJ tandem, [109] and SHJ [110] solar cells as a function of wavelength. The absorptance curve of different transparent electrodes measured on glass is also shown for comparison of the relevant wavelength range to be taken into account when developing transparent electrodes for solar cells.…”

Electrohydrodynamic NanoDrip Printing of High Aspect Ratio Metal Grid Transparent Electrodes

“…Moreover, the brittleness of the ceramic ITO fi lms can present a bottleneck in the fabrication of highly fl exible devices. [ 5 ] These disadvantages have motivated recent research efforts toward alternative material systems such as carbon nanotube [ 6 ] or silver nanowire (AgNW) networks, [ 7,8 ] metallized electrospun nanowires, [ 9,10 ] graphene layers, [ 11 ] ultrathin metal fi lms, [ 12 ] self-forming [ 13 ] or patterned metal grids. [14][15][16][17][18][19][20] Ideally, besides having very good electrical and optical performance, the new system should be low cost, fl exible and include direct patterning.…”