Lightweight and Flexible Heat Sink from Carbon Nanotube Sheet

A heat sink for dissipating heat from a heat – generating apparatus includes one or more thermally conductive struc tures extending from , and in heat – conducting contact with , the heat – generating apparatus . The thermally conductive structures include sheets including carbon nanotubes , gra phene , or boron nitride . The one or more thermally conduc tive structures are attached to the heat – generating apparatus in a configuration designed to dissipate heat from the heat – generating apparatus . Techniques for making a heat sink , and techniques of cooling a heat – generating apparatus are also described.

We claim : 1 . A heat sink for dissipating heat from a heat – generating apparatus , the heat sink comprising : one or more thermally conductive structures extending from , and in heat – conducting contact with , the heat generating apparatus , wherein the thermally conductive structures comprise sheets comprising carbon nano tubes , graphene , or boron nitride , wherein the one or more thermally conductive structures are attached to the heat – generating apparatus in a configuration designed to dissipate heat from the heat generating apparatus . 2 . The heat sink of claim 1 , wherein the one or more thermally conductive structures comprise a sheet consisting of a network of carbon nanotubes . 3 . The heat sink of claim 2 , wherein the network of carbon nanotubes has been heat treated to reduce or remove residual processing surfactants and / or surface impurities on the net work . 4 . The heat sink of claim 2 , wherein the carbon nanotubes of the sheet have a specific surface area from 100 m?lg to 350 m – / g . 5 . The heat sink of claim 1 , wherein the one or more thermally conductive structures comprise two or more cool ing fins formed from a buckypaper sheet . 6 . The heat sink of claim 1 , wherein the heat – generating apparatus comprises one or more LEDs . 7 . The heat sink of claim 1 , wherein the one or more thermally conductive structures comprise a plurality of cooling fins in spaced part relation to one another , wherein at least one edge of each fin is connected to the heat generating apparatus with the fin having a body extending away therefrom . 8 . A cooling fin apparatus , comprising : a plurality of carbon nanotube sheets arranged in spaced relation to one another , and a base to which a proximal edge of each of the carbon nanotube sheets is fixed , each sheet extending away from the base toward a distal edge . 9 . The cooling fin apparatus of claim 8 , wherein the carbon nanotube sheets each consists of a heat treated network of multiwall carbon nanotubes . 10 . The cooling fin apparatus of claim 8 , wherein the carbon nanotube sheets comprise at least one layer of a heat treated network of multiwall carbon nanotubes and at least one thermally conductive layer which comprises an epoxy combined with graphite – nanoplatelets and / or carbon fibers . 11 . A method of making a heat sink , comprising : forming a sheet which comprises a network of carbon nanotubes ; and cutting and / or folding the sheet into a configuration adapted to dissipate heat from a heat – generating appa ratus . 12 . The method of claim 11 , further comprising heat treating the sheet to reduce or remove surface impurities on the network . 13 . The method of claim 11 , wherein the configuration comprises a plurality of cooling fins . 14 . A method of cooling a heat – generating apparatus , comprising : operating the apparatus to produce heat ; and cooling the apparatus by conducting the heat away from the apparatus via one or more thermally conductive structures extending from , and in heat – conducting con tact with , the apparatus , wherein the thermally conductive structures comprise sheets comprising carbon nanotubes , graphene , or boron nitride .