Self-assembly ordered domain configurations serve the high electromechanical response lead-free thin films

Micro-electromechanical systems (MEMS) urgently require high-performance lead-free piezoelectric thin films, which is rather difficult to achieve via the existing strategy of designing a morphotropic phase boundary. How to update the optimization methods for piezoelectric performance is a challenge. Here, we proposed a simple and interesting way, that is, constructing the self-assembly ordered domain configurations in our oriented lead-free thin films. Driven by the local strain, we realized a periodic arrangement of disordered nano-domains and ordered striped domain structures, and thus obtained an outstanding electrostrain of 1.55%. Multi-scale characterization and phase-field simulations suggest the underlying mechanism of this giant strain as the synergy between the high polarization brought about by the periodic nano-pillar-like striped domains, the highly sensitive electrical stimulation response of defective dipoles and disordered nano-domains. The presented high electrostrain supports the potential MEMS application, the proposed optimization strategy serves the next generation lead-free thin films with higher electromechanical response.