Lawrence Berkeley National Laboratory

The ability to control thermal transport is critical for the design of thermal rectifiers, logic gates, and transistors, although it remains a challenge to design materials that exhibit large changes in thermal conductivity with switching ratios suitable for practical applications. Here, we propose the use of flexible metal-organic frameworks, which can undergo significant structural changes in response to various stimuli, to achieve tunable switchable thermal conductivity. In particular, we use molecular dynamics simulations to show that the thermal conductivity of the flexible framework Fe(bdp) (bdp2- = 1,4-benzenedipyrazolate) becomes highly anisotropic upon transitioning from the expanded to the collapsed phase, with the conductivity decreasing by nearly an order of magnitude along the direction of compression. Our results add to a small but growing number of studies investigating metal-organic frameworks for thermal transport.