Case 14985

Azobenzene Functionalized Carbon Nanotubes and Other Templated Photoswitch Molecules for High Energy Density Solar Thermal Fuels


Solar thermal fuels, renewable energy, photoswitch, carbon nanotubes, density functional theory


Clean, renewable, and transportable energy conversion/storage


Large-scale adoption of solar thermal fuels requires enhanced energy storage capacity and thermal stability. Previous solar thermal fuels degraded after only a few cycles of energy conversion and release and/or were composed of expensive, non-abundant elements.


The invention suggests a new approach to the design of high-energy density solar thermal fuels based on combining well-studied photoswitch molecules with carbon nanotubes to increase energy storage capacity and thermal stability of the photoswitch molecules. The novel solar thermal fuel is composed of azobenzene-functionalized carbon nanotubes and can have both volumetric and gravimetric energy densities comparable to that of Li-ion batteries.

  • No emissions
  • Easily transportable in liquid or powder form
  • Easy to recharge
  • Can cycle through energy conversion and release numerous times without degradation
  • CNT substrate imposes close-packed, highly ordered array of adsorbed photomolecules, which leads to increased volumetric energy density
  • Enables systematic manipulation of the inter- and intra-molecular interactions, creating a highly effective set of tuning parameters for maximizing both energy storage capacity and storage lifetime of the solar thermal fuel

  • Professor Jeffrey C. Grossman (Department of Material Science and Engineering, MIT)
  • Alexis M. Kolpak (Department of Material Science and Engineering, MIT)

Intellectual Property:

US Patent Application 61/479529 filed 4/27/2011

PCT Patent Application PCT/US2012/035379


A. M. Kolpak and J. C. Grossman, “Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels,” Nano Letters 11, 3156-3162 (2011).

MIT News (10/26/2010): “Catching the sun's heat: Storing thermal energy in chemical form has the potential to make it indefinitely storable and transportable”

MIT News (7/13/2011): “Research Update: New Way to Store Sun’s Heat”

Last revised: November 15, 2011

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