Electronic Materials and Device Research Center, Korea Electronics Technology Institute, Gyeonggi-do 463-816, Korea.
ACS Nano. 2013 Jul 23;7(7):5769-76. doi: 10.1021/nn400358x. Epub 2013 Jun 18.
Large-scale integration of vanadium dioxide (VO2) on mechanically flexible substrates is critical to the realization of flexible smart window films that can respond to environmental temperatures to modulate light transmittance. Until now, the formation of highly crystalline and stoichiometric VO2 on flexible substrate has not been demonstrated due to the high-temperature condition for VO2 growth. Here, we demonstrate a VO2-based thermochromic film with unprecedented mechanical flexibility by employing graphene as a versatile platform for VO2. The graphene effectively functions as an atomically thin, flexible, yet robust support which enables the formation of stoichiometric VO2 crystals with temperature-driven phase transition characteristics. The graphene-supported VO2 was capable of being transferred to a plastic substrate, forming a new type of flexible thermochromic film. The flexible VO2 films were then integrated into the mock-up house, exhibiting its efficient operation to reduce the in-house temperature under infrared irradiation. These results provide important progress for the fabrication of flexible thermochromic films for energy-saving windows.
在机械柔性衬底上大规模集成二氧化钒（VO2）对于实现能够响应环境温度来调节光透过率的柔性智能窗膜至关重要。到目前为止，由于 VO2 生长的高温条件，尚未在柔性衬底上展示出高结晶度和化学计量比的 VO2。在这里，我们通过使用石墨烯作为 VO2 的通用平台，展示了一种具有前所未有的机械柔韧性的基于 VO2 的热致变色膜。石墨烯有效地作为原子薄、柔性但坚固的支撑，从而能够形成具有温度驱动相变特性的化学计量比 VO2 晶体。石墨烯支撑的 VO2 能够转移到塑料衬底上，形成一种新型的柔性热致变色膜。然后，将柔性 VO2 薄膜集成到模拟房屋中，展示了其在红外辐射下降低室内温度的有效运行。这些结果为制造用于节能窗的柔性热致变色膜提供了重要进展。
