Ultrahigh-power-density flexible piezoelectric energy harvester based on freestanding ferroelectric oxide thin films
Zhongqi Ren, Shiqing Deng, Junda Shao, Yangyang Si, Chao Zhou, Jingjing Luo, Tao Wang, Jinyang Li, Jingxuan Li, Haipeng Liu, Xueqiang Qi, Peike Wang, Ao Yin, Lijun Wu, Suzhu Yu, Yimei Zhu, Jun Chen, Sujit Das, Jun Wei, Zuhuang Chen
Abstract
Flexible piezoelectric nanogenerators are emerging as a promising solution for powering next-generation flexible electronics by converting mechanical energy into electrical energy. However, traditional ferroelectric ceramics, despite their excellent piezoelectric properties, lack flexibility; while piezoelectric polymers, although highly flexible, have low piezoelectricity. The quest to develop materials that combine high piezoelectricity with exceptional flexibility has thus become a research focus. Herein, we present a breakthrough in this field with the fabrication of freestanding (111)-oriented PbZr0.52Ti0.48O3 single crystalline thin films, which exhibit remarkable flexibility and a high converse piezoelectric coefficient (~585 pm/V). This is achieved through water-soluble sacrificial layer to relieve substrate clamping and controlling the crystal orientation to further enhance the piezoelectric response. Our nanogenerators, constructed using these freestanding nanoscale membranes, demonstrate a record-high output power density (~63.5 mW/cm3), excellent flexibility (with a strain tolerance >3.4%), and superior mechanical stability in cycling tests (>60,000 cycles). These advancements pave the way for high-performance, flexible electronic devices utilizing ferroelectric oxide thin films. The piezoelectricity of ferroelectric oxide films is limited by substrate clamping, and their rigidity hinders their applications in flexible electronics. Herein, authors report freestanding PbZr0.52Ti0.48O3 nanoscale membranes with both high piezoelectricity and high flexibility.