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

Abstract A combined process of nanoimprint lithography and dual‐side aligned photolithography to address misalignment of subsequent layers for the fabrication of SiN_x nanoporous membrane filters (SiN_x nanofilter) is suggested. Here, in one process, 21 SiN_x nanofilter chips are fabricated on a 6 inch Si wafer by aligning nanopore area of nanofilter and template area of nanofilter chip. An SiN_x 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 SiN_x 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 SiN_x nanofilter chips for chemical species sieving and other applications.