Porous film impregnation method for record-efficiency visible-to-UV photon upconversion and subsolar light harvesting

Photon upconversion from visible light to ultraviolet (UV) light is useful for various photochemical reactions such as artificial photosynthesis, but its efficiency is low under practical film conditions. Here, we demonstrate a film with a record-high visible-to-UV upconversion efficiency of 27.6% by simply soaking a porous film with a low-volatile upconversion solution. Furthermore, by combining this film with a microlens array, a significantly low threshold excitation light intensity of less than 0.60 mW cm-2, at least one order of magnitude lower than solar irradiance, is achieved.

从可见光到紫外光的光子上转换对于诸如人工光合作用等各种光化学反应是有用的，但在实际薄膜条件下其效率较低。在此，我们通过简单地用一种低挥发性上转换溶液浸泡多孔薄膜，展示了一种具有创纪录的27.6%的可见光到紫外光上转换效率的薄膜。此外，通过将这种薄膜与微透镜阵列相结合，实现了低于0.60毫瓦每平方厘米的极低阈值激发光强度，该强度至少比太阳辐照度低一个数量级。