Gas Phase Single Nanoparticle Characterisation

纳米颗粒样品受到物理和化学异质性的影响。这导致了技术应用中的性能下降。性能优化需要深入了解单个纳米粒子的内在属性，以及它们如何对整体属性做出贡献。然而，大多数单纳米颗粒技术探测的是沉积的颗粒，其性质受到载体或邻近颗粒的干扰。探测真正的固有性质需要将纳米颗粒隔离在气相中。在这里，我建议开发突破性的、超灵敏的质谱学和激光光谱分析工具来研究分离在气相中的单个纳米粒子。尺寸在5到100纳米之间的带电金属、半导体和绝缘体纳米粒子将被捕获在一个充满缓冲气体的、可控温度(10-300K)的低温四极离子陷阱中，该离子陷阱针对光谱学进行了优化。单个捕获的纳米粒子的绝对质量和绝对电荷将通过光学手段非破坏性地和准连续地确定。程序升温解吸质谱、UV/Vis作用光谱和分散荧光光谱将被用来精确地确定单个半导体纳米晶体的温度和表征其光学性质，研究裸露和包覆的金属纳米颗粒中的等离子体激发，并监测荧光纳米金刚石中能量转换的时间演化。总体目标是建立一个新的单一纳米颗粒表征工具集，允许解剖纳米颗粒的异质性，以便改善纳米颗粒在所有学科中的应用性能，例如纳米传感器的灵敏度、纳米催化剂的选择性或药物纳米载体的效率。

Nanoparticle samples suffer from physical as well as chemical heterogeneity. This leads to a reduced performance in technological applications. Performance optimisation requires obtaining insights into the intrinsic properties of individual nanoparticles and how they contribute to the properties of the ensemble. Most single nanoparticle techniques, however, probe deposited particles, whose properties are perturbed, either by the support or neighbouring particles. Probing truly inherent properties requires isolating nanoparticles in the gas phase. Here, I propose to develop groundbreaking, ultrasensitive mass spectrometric and laser spectroscopic tools to study single nanoparticles isolated in the gas phase. Charged metal, semiconductor and insulator nanoparticles in the size range from 5 to 100 nm will be trapped in a buffer-gas filled, temperature-controlled (10-300 K) cryogenic quadrupole ion-trap optimised for spectroscopy. The absolute mass and absolute charge of single, trapped nanoparticles will be determined non-destructively and quasi-continuously by optical means. Temperature-programmed desorption mass spectrometry, UV/Vis action spectroscopy and dispersed fluorescence spectroscopy will be used to accurately determine the temperature and characterise the optical properties of single semiconductor nanocrystals, to study plasmonic excitations in bare and coated metal nanoparticles, and to monitor the temporal evolution of energy conversion in fluorescent nanodiamonds. The overarching goal is to establish a novel single nanoparticle characterisation tool set that allows dissecting nanoparticle heterogeneity in order to improve the performance of nanoparticle applications across all disciplines, e.g., the sensitivity of nanosensors, the selectivity of nanocatalysts or the efficiency of drug nanocarriers.