Monodisperse colloidal silica with excellent batch-to-batch reproducibility by stoichiometric seeded growth strategy

Abstract

Monodisperse colloidal silica have been extensively used as models for inter-particle interaction investigation, standards for instrument calibration and polishing agents for global planarization of wafer in integrated circuit manufacturing. Despite marvelous achievements made for colloidal silica synthesis in the past decades, a long-standing challenge for massive production of colloidal silica lies in the batch-to-batch reproducibility. Herein, we present a stoichiometric seeded growth strategy for the massive production of monodisperse colloidal silica, where the silica precursors are designed to exclusively condense on the surface of seed particles with single Q4 Si species, enabling a precise control of resultant colloidal silica size by the feeding precursor/seed ratios, and consequently, achieving excellent batch-to-batch reproducibility. Governed by the stoichiometric correlation, customized size of colloidal silica at high precision (∼1 nm in diameter) can be prepared in large quantity. More importantly, this seeded growth strategy has rather high tolerance on the size distribution of seed particles; monodisperse colloidal silica can be readily obtained from even polydisperse seed particles, significantly lowing the cost of monodisperse particles, therefore, highlighting the feasibility of large-scale application of monodisperse colloidal silica.