Temperature sensors with unique temperature-dependent luminescent properties have a great advantage to be used as noncontact luminescence thermometers especially in biological applications. To date, most of the photoluminescent materials for temperature sensing are based on the temperature-dependent luminescent intensity or short-lived emission lifetime, which suffer from the interference from excitation power, sample concentration, or background fluorescence. Herein, we report a carbon dot (CD)-based nanocomposite showing distinct long-lived thermally activated delayed fluorescence (TADF) property with the lifetime of 30.85 ms at room temperature and under an air atmosphere. Notably, the TADF emission presents variable long-lived lifetimes under different temperatures, which demonstrates its promising application in lifetime thermal sensing. The interaction between the functional groups of CD and SiO₂ matrix by forming Si–O–C bonds plays a key role for the synthesis process, which further improves the confinement of vibrations and rotation and harvests the triplet state efficiently. This work introduces a new perspective to prepare nanothermometers, which opens up the potential application of CD-based materials with long-lived TADF emission in highly sensitive temperature sensing with their convenience and high efficiency.

具有独特的随温度变化的发光特性的温度传感器具有很大的优势，可以用作非接触式发光温度计，尤其是在生物应用中。迄今为止，大多数用于温度感测的光致发光材料都是基于与温度相关的发光强度或寿命短的发射寿命，它们受到激发功率，样品浓度或背景荧光的干扰。本文中，我们报道了一种基于碳点（CD）的纳米复合材料，该复合材料在室温和大气中的寿命为30.85 ms，显示出独特的长寿命热活化延迟荧光（TADF）特性。值得注意的是，TADF发射在不同温度下具有可变的长寿命，这证明了其在寿命热传感中的应用前景广阔。通过形成Si–O–C键的₂基体在合成过程中起着关键作用，它进一步改善了振动和旋转的限制并有效地捕获了三重态。这项工作为制备纳米温度计引入了一个新的视角，它以其方便，高效的优势，将具有长寿命TADF发射的CD基材料在高灵敏度温度感测中的潜在应用开辟了道路。