All forms of energy follow the law of conservation of energy, by which they can be neither created nor destroyed. Light-to-heat conversion as a traditional yet constantly evolving means of converting light into thermal energy has been of enduring appeal to researchers and the public. With the continuous development of advanced nanotechnologies, a variety of photothermal nanomaterials have been endowed with excellent light harvesting and photothermal conversion capabilities for exploring fascinating and prospective applications. Herein we review the latest progresses on photothermal nanomaterials, with a focus on their underlying mechanisms as powerful light-to-heat converters. We present an extensive catalogue of nanostructured photothermal materials, including metallic/semiconductor structures, carbon materials, organic polymers, and two-dimensional materials. The proper material selection and rational structural design for improving the photothermal performance are then discussed. We also provide a representative overview of the latest techniques for probing photothermally generated heat at the nanoscale. We finally review the recent significant developments of photothermal applications and give a brief outlook on the current challenges and future directions of photothermal nanomaterials.

中文翻译：

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光热纳米材料：强大的光热转换器

一切形式的能量都遵循能量守恒定律，既不能被创造也不能被消灭。光热转换作为一种传统但不断发展的将光能转换为热能的方法，一直对研究人员和公众具有持久的吸引力。随着先进纳米技术的不断发展，各种光热纳米材料被赋予了优异的光捕获和光热转换能力，探索着令人着迷和具有前瞻性的应用。在此，我们回顾了光热纳米材料的最新进展，重点关注它们作为强大的光热转换器的潜在机制。我们提供了广泛的纳米结构光热材料目录，包括金属/半导体结构、碳材料、有机聚合物、和二维材料。然后讨论了适当的材料选择和合理的结构设计以提高光热性能。我们还提供了有关在纳米尺度上探测光热产生的热量的最新技术的代表性概述。最后，我们回顾了近期光热应用的重大进展，并对光热纳米材料当前面临的挑战和未来发展方向进行了简要展望。