While numerous near-infrared (NIR) materials have emerged, most of them are strongly colored or black due to the absorption band or tails in the visible region. Here, a highly transparent and soluble NIR-absorbing ionic salt, isobutyl-substituted diimmonium borate (IDI), is synthesized and fabricated, through a solution process, as a thin film that shows a transmittance of over 93% in the whole visible region. A transparent photothermal (PT) film heater is fabricated with the IDI-doped polymer solution, which shows a photothermal conversion efficiency (ηPT ) of 75.2%. Additionally, the prepared PT heater shows a high water evaporation conversion efficiency (ηw ) of 68.8% upon exposure to a 1064 nm laser. Furthermore, the transparent IDI film affords the development of a wireless transparent actuator for the first time, generating a bending angle over 75°, with over 2700 bending cycles. The transparent IDI film creates a hot transparent Venus flytrap and a colorful or fluorescent actuator upon the addition of colorants without losing the actuation properties.

中文翻译：

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吸收NIR的可溶性二亚胺盐制成的透明光热加热器。

尽管出现了许多近红外（NIR）材料，但由于可见区中的吸收带或尾部，大多数材料还是深色或黑色。在此，通过溶液法合成并制备了高度透明且可溶的吸收NIR的离子盐，即异丁基取代的硼酸二铵（IDI），制成在整个可见光区域显示超过93％的透射率的薄膜。用掺杂了IDI的聚合物溶液制造了透明的光热（PT）薄膜加热器，该加热器显示出75.2％的光热转换效率（ηPT）。另外，所制备的PT加热器在暴露于1064nm激光时显示出68.8％的高水蒸发转化效率（ηw）。此外，透明的IDI薄膜首次为无线透明致动器的开发提供了条件，产生超过75°的弯曲角度，超过2700个弯曲周期。透明的IDI膜在添加着色剂时会形成热透明的维纳斯捕蝇器和彩色或荧光致动器，而不会失去致动性能。