Laser-induced hierarchically-structured materials from block copolymer self-assembly

Hierarchically porous structured materials with multifunctional properties and higher order complexities are highly desirable for many applications such as separation and energy storage. Here we describe the generation of hierarchically porous organic and inorganic structures coupling block copolymer self-assembly with spatially- and temporally controlled laser irradiation. A simple and rapid laser irradiation of block copolymer-directed hybrid films with a continuous wave laser in the sub-millisecond timescales enabled synthesis of 3D mesoporous polymer structures and shapes. Backfilling the polymer template with amorphous silicon followed by pulsed laser annealing enabled transient melt transformation of amorphous precursors into 3D mesoporous crystalline silicon nanostructures. Mechanistic studies on laser-induced crystalline silicon nanostructure formation during the nanosecond silicon melt-crystallization process and polymer template stability at temperatures above 1250 degrees Celsius are highlighted. Ministry of Education (MOE) Accepted version Singapore Ministry of Education AcRF Tier 1 grant (2018-T1-001-084)