Fabrication of SiNx Nanopore Filters Using Combined Process of Nanoimprint and Dual-Side Aligned Photolithography for Purified Cs3MnBr5 Green Phosphors

A combined process of nanoimprint lithography and dual-side aligned photolithography to address misalignment of subsequent layers for the fabrication of SiNx nanoporous membrane filters (SiNx nanofilter) is suggested. Here, in one process, 21 SiNx nanofilter chips are fabricated on a 6 inch Si wafer by aligning nanopore area of nanofilter and template area of nanofilter chip. An SiNx nanofilter chip-integrated fluidic device is used to test the purification ability of the nanofilter in terms of its pore size and surface hydrophobicity or hydrophilicity. This is the first attempt at separating unnecessary chemical residues from a mixed reactant solution by nanoscale purification process using the tremendous number of nanoholes in the nanofilter. After purification by the nanofilter, high efficiency and narrow-band Cs3MnBr5 phosphor is synthesized by evaporative crystallization. Here, the photoluminescent quantum yield (PLQY) of the purified Cs3MnBr5 phosphor is monitored to evaluate the purification ability of the SiNx nanofilter. The highest PLQY (53%) of Cs3MnBr5 green phosphors is obtained by purification of reactant solution using nanofilter with 50 nm nanopore diameter and hydrophilic surface. This combined process proves its potential for scalable manufacturing of complex designed SiNx nanofilter chips for chemical species sieving and other applications.