School of Science Department of Chemistry 2 Department of Chemistry Ultrafast Spectroscopic Study of Aggregation-Induced Emission (AIE) Materials Supervisor: CHEN Tengteng / CHEM Student: WANG Maiqi / CHEM Course: UROP 1100, Summer Despite their similar photoluminescence behavior upon aggregation, the excited-state dynamics of aggregation-induced emission (AIE) and cluster-triggered emission (CTE) luminogens remain poorly understood. This study employs transient absorption (TA) spectroscopy to directly compare the relaxation mechanisms of tetraphenylethylene (TPE), a classic AIE luminogen, with a sterically modified CTE-active derivative 1,1,2,2-tetraphenylethane (s-TPE). Complementary UV/Vis absorption and photoluminescence (PL) spectroscopy provide essential ground-state and steady-state emission characterization. While both systems exhibit visible emission in the aggregated state, their relaxation pathways differ significantly: TPE follows sequential conformational relaxation, whereas s-TPE shows excitation wavelength-dependent parallel processes. These mechanistic insights are crucial for optimizing luminogen performance in organic optoelectronic devices (e.g., OLEDs) and bioimaging applications. Construction and Application of Surface Enhanced Raman Spectrometer in Biomolecules Characterization Supervisor: HUANG Jinqing / CHEM Student: CHU Kwan Ho / CHEM Course: UROP 1100, Spring UROP 2100, Summer Soil nutrients play a vital role in ecosystem health and agricultural productivity, yet their excessive or deficient concentrations can disrupt ecosystems. Accurate monitoring of nutrient concentrations is essential for sustainable land management. Traditional analytical methods, such as chromatography and atomic absorption spectroscopy, often require extensive sample preparation and lack field-deployable capabilities. To overcome these limitations, we developed an advanced optical sensing approach utilizing silver nanomaterials, which enhance detection sensitivity through plasmonic effects. In this study, we prepared soil samples with varying nutrient concentrations, conducted optical analysis using a portable spectrometer system and utilized the silver nanomaterials. Our results demonstrate that this nanomaterial-enhanced approach enables rapid, sensitive, and on-site detection of soil nutrients, offering significant advantages over conventional methods for environmental monitoring applications.
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