无机卤化物钙钛矿量子点微球腔荧光增强自参考温度传感研究

Self-reference Temperature Sensing via Fluorescence Enhancement of Microsphere-cavity-coupled Inorganic Halide Perovskite Quantum Dots

利用稀土离子掺杂材料、有机染料以及量子点等荧光材料实现荧光温度传感在航空航天、生物医疗、食品储存等领域具有重要意义。其中,无机卤化物钙钛矿量子点(PeQDs)荧光材料由于具有量子产率高,温度依赖性强等特点,在荧光温度传感领域展现了巨大的应用前景。然而,PeQDs只有一个光致荧光(PL)峰,其强度和位置极易受到浓度和尺寸等因素的干扰,因此用单一PL峰进行温度传感的准确性较低。在本工作中,我们提出了一种微球腔阵列(MCA)耦合PeQDs薄膜(MCA/PeQDs)的新型温度传感结构,利用MCA/PeQDs结构与PeQDs薄膜具有温度依赖性的PL峰值强度比实现温度传感。该结构通过微球腔中回音壁模式(WGMs)增强的Purcell效应提高了自发辐射速率,抑制了声子辅助猝灭效应,从而实现了较好的PeQDs荧光增强。结果表明,在223~373 K范围内,当PeQDs浓度为0.1316 mg/mL、微球腔直径为(19±1)μm时,该结构的绝对灵敏度(S_(a))与相对灵敏度(S_(r))可达到0.75 K^(-1)和1.95%·K^(-1)。本工作克服了使用单个PL峰进行温度传感准确性差的缺点,为荧光材料在高性能荧光温度传感器中的应用开辟了新的途径。

Rare earth ions doped materials,organic dyes and quantum dots are employed to realize the fluorescence temperature sensing which has great significance in aerospace,biomedicine,food storage,etc.Fluorescent materials of inorganic halide perovskite QDs(PeQDs)possess great application prospects in the field of fluorescence temperature sensing due to high quantum yield and strong temperature dependence.However,PeQDs have only one photoluminescence(PL)peak whose intensity and position are highly susceptible to interference from factors such as concentration and size,resulting in low accuracy in temperature sensing using this PL peak alone.In this work,we propose a novel temperature sensing structure using microsphere-cavity-array(MCA)capped PeQDs film(MCA/PeQDs).Fluorescence temperature sensing is realized using the temperature dependent PL peak intensity ratio between the MCA/PeQDs structure and the bare one.Through the Purcell effect induced by microsphere cavity supported whispering-gallery modes(WGMs)in the microsphere cavity,the spontaneous emission rate is enhanced,and the phonon assisted thermal quenching effect is suppressed,which results in better fluorescence enhancement of PeQDs.As a result,when the concentration of PeQDs is 0.1316 mg/mL and the diameter of the microsphere is(19±1)μm,the absolute sensitivity(S_(a))and relative sensitivity(S_(r))can achieve 0.75 K^(-1) and 1.95%·K^(-1).The present work over⁃comes the poor accuracy of temperature sensing in single PL peak and opens up a new way for fluorescence materials used in fluorescence temperature sensing with high performance.