Semiconductor nanocrystals, also called quantum dots (QDs), have been proven as powerful fluorescent probes. This paper presents a new method to evaluate the retention efficiency of nanofiltration membranes using sub-10 nm fluorescent QDs in organic solvents. Two different Cd-based QDs with uniformed sizes (nominal 8 nm and 4 nm) were used as challenge particles in this study. Fluorescence spectrophotometer was used as a detector to measure the QDs concentration before and after filtration. High resolution transmission electron microscope (HRTEM) and dynamic light scattering (DLS) were employed for measuring particle size and size distribution, which revealed the QDs used in this study were with a narrow size distribution. Three different types of Entegris UPE membranes were tested by using this method. The filters were rated at 3 nm, 5 nm and 10 nm using bubble-point extrapolative methods were further confirmed by the QDs retention tests in solvents.

Date Published: 10 April 2013
PDF: 6 pages
Proc. SPIE 8681, Metrology, Inspection, and Process Control for Microlithography XXVII, 86811R (10 April 2013); doi: 10.1117/12.2011614

Published in SPIE Proceedings Vol. 8681:
Metrology, Inspection, and Process Control for Microlithography XXVII
Alexander Starikov; Jason P. Cain, Editor(s)