A room-temperature moisture-stabilized metal-free energetic ferroelectric material for piezoelectric generation

Abstract

Metal-free molecule-based ferroelectrics that are degradable and exhibit tunable structures, low production costs, and “soft” textures have prospects for sensing and piezoelectric generation applications, but the instances integrating multiple functionalities are very rare. Herein, we proved that an energetic material based on ternary perchlorate salt, (1-methyl-1,4-diazabicyclo-[2.2.2]octane-1,4-diium)(NH₄)(ClO₄)₃ (DAP-M4), is simultaneously a rare room-temperature ferroelectric crystal with a low hygroscopicity (a weight increase of less than 0.02% under 100% relative humility), an ultrawide band gap of 5.4 eV, “soft” mechanical properties (Young's modulus less than 23.68 GPa), and an exploitable piezoelectricity (d₃₄ = 5.24 pC N⁻¹). Moreover, its potential piezoelectric generation application was demonstrated by an easily fabricated DAP-M4/TPU (thermoplastic polyurethane) composite film with an open-circuit voltage of 3.5 V and a short-circuit current of 0.5 μA. Being a novel energetic ferroelectric material with simultaneously excellent energetic and optical–electrical properties, DAP-M4 provides an attractive possibility for assembling highly integrated functional and self-destructive devices, and inspires the design of next-generation multi-functional materials based on diverse molecular components.