Transparent conducting film

Figure 1. Cross-section of thin film polycrystalline solar cell. The transparent conducting coating contacts the n-type semiconductor to draw current.

Transparent conducting films (TCFs) are thin films of optically transparent and electrically conductive material. They are an important component in a number of electronic devices including liquid-crystal displays, OLEDs, touchscreens and photovoltaics.[1][2] While indium tin oxide (ITO) is the most widely used, alternatives include wider-spectrum transparent conductive oxides (TCOs),[3][4] conductive polymers, metal grids and random metallic networks,[5][6][7] carbon nanotubes[8][1] (CNT), graphene,[1] nanowire meshes[1] and ultra thin metal films.[9]

TCFs for photovoltaic applications have been fabricated from both inorganic and organic materials. Inorganic films typically are made up of a layer of transparent conducting oxide (TCO),[10] most commonly indium tin oxide (ITO), fluorine doped tin oxide (FTO),[11] niobium doped anatase TiO2 (NTO)[12] or doped zinc oxide. Organic films are being developed using carbon nanotube networks and graphene, which can be fabricated to be highly transparent to infrared light, along with networks of polymers such as poly(3,4-ethylenedioxythiophene) and its derivatives.

Transparent conducting films are typically used as electrodes when a situation calls for low resistance electrical contacts without blocking light (e.g. LEDs, photovoltaics). Transparent materials possess wide bandgaps whose energy value is greater than those of visible light. As such, photons with energies below the bandgap value are not absorbed by these materials and visible light passes through. Some applications, such as solar cells, often require a wider range of transparency beyond visible light to make efficient use of the full solar spectrum.

  1. ^ a b c d Hecht, D. S; Hu; Irvin, G. (2011). "Emerging Transparent Electrodes Based on Thin Films of Carbon Nanotubes, Graphene and Metallic Nanostructures". Advanced Materials. 23 (13): 1482–1513. Bibcode:2011AdM....23.1482H. doi:10.1002/adma.201003188. PMID 21322065. S2CID 197299452.
  2. ^ Manwani, K; Panda, E (2021). "Thickness induced modifications in the valence, conduction bands and optoelectronic properties of undoped and Nb-doped anatase TiO2 thin films". Materials Science in Semiconductor Processing. 134: 106048. doi:10.1016/j.mssp.2021.106048.
  3. ^ Dhakal, Tara, et al. "Transmittance from visible to mid infra-red in AZO films grown by atomic layer deposition system." Solar Energy 86.5 (2012): 1306-1312. | https://doi.org/10.1016/j.solener.2012.01.022
  4. ^ Wan, J; Xu, Y; Ozdemir, B (2017). "Tunable Broadband Nanocarbon Transparent Conductor by Electrochemical Intercalation". ACS Nano. 11 (1): 788–796. Bibcode:2017Nano...11..788W. doi:10.1021/acsnano.6b07191. PMID 28033469.
  5. ^ Gao, Jinwei (February 12, 2014). "Uniform Self-Forming Metallic Network as a High-Performance Transparent Conductive Electrode". Advanced Materials. 26 (6): 873–877. Bibcode:2014AdM....26..873H. doi:10.1002/adma.201302950. PMID 24510662. S2CID 205251636.
  6. ^ Gao, Jinwei (28 November 2014). "Bio-inspired networks for optoelectronic applications". Nature Communications. 5 (5674): 5674. Bibcode:2014NatCo...5.5674H. doi:10.1038/ncomms6674. PMID 25430671.
  7. ^ Gao, Jinwei (26 September 2016). "Optimization of hierarchical structure and nanoscale-enabled plasmonic refraction for window electrodes in photovoltaics". Nature Communications. 7 (12825): 12825. Bibcode:2016NatCo...712825H. doi:10.1038/ncomms12825. PMC 5052667. PMID 27667099.
  8. ^ Wu, Zhuangchun, et al. "Transparent, conductive carbon nanotube films." Science 305.5688 (2004): 1273-1276.
  9. ^ Ren, Xingang (2015). "Optically enhanced semi-transparent organic solar cells through hybrid metal/nanoparticle/dielectric nanostructure". Nano Energy. 17: 187–195. doi:10.1016/j.nanoen.2015.08.014.
  10. ^ Conductive Oxide Thin Films Archived 2013-10-03 at the Wayback Machine Materion Technical Paper, "Transparent Conductive Oxide Thin Films"
  11. ^ Swallow, J. E. N.; et al. (2017). "Self-compensation in transparent conducting F-doped SnO2". Advanced Functional Materials. 28 (4): 1701900. doi:10.1002/adfm.201701900.
  12. ^ Manwani, K; Panda, E (2021). "Thickness induced modifications in the valence, conduction bands and optoelectronic properties of undoped and Nb-doped anatase TiO2 thin films". Materials Science in Semiconductor Processing. 134: 106048. doi:10.1016/j.mssp.2021.106048.