A Self‐Powered UV Photodetector With Ultrahigh Responsivity Based on 2D Perovskite Ferroelectric Films With Mixed Spacer Cations

• Published in: Advanced materials (Weinheim) 2023-11, Vol.35 (47), p.e2301705-n/a
• Main Authors: Guo, Linjuan, Qi, Yaqian, Wu, Zihao, Yang, Xiaoran, Yan, Guoying, Cong, Ridong, Zhao, Lei, Zhang, Wei, Wang, Shufang, Pan, Caofeng, Yang, Zheng
• Format: Article
• Language: English
• Subjects: Cations; Crystal growth; Electric fields; ferroelectric film; Ferroelectric materials; Ferroelectricity; Ferroelectrics; ferro–pyro–phototronic effect; Materials science; Metal halides; mixed 2D perovskites; Optoelectronics; Perovskites; Photoelectric effect; Photoelectricity; Photometers; Piezoelectricity; piezo–phototronic effect; self‐powered photodetectors; Two dimensional materials
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202301705

Self‐powered photodetectors (PDs) have the advantages of no external power requirement, wireless operation, and long life. Spontaneous ferroelectric polarizations can significantly increase built‐in electric field intensity, showing great potential in self‐powered photodetection. Moreover, ferroelectrics possess pyroelectric and piezoelectric properties, beneficial for enhancing self‐powered PDs. 2D metal halide perovskites (MHPs), which have ferroelectric properties, are suitable for fabricating high‐performance self‐powered PDs. However, the research on 2D metal halide perovskites ferroelectrics focuses on growing bulk crystals. Herein, 2D ferroelectric perovskite films with mixed spacer cations for self‐powered PDs are demonstrated by mixing Ruddlesden–Popper (RP)‐type and Dion–Jacobson (DJ)‐type perovskite. The (BDA0.7(BA2)0.3)(EA)2Pb3Br10 film possesses, overall, the best film qualities with the best crystalline quality, lowest trap density, good phase purity, and obvious ferroelectricity. Based on the ferro–pyro–phototronic effect, the PD at 360 nm exhibits excellent photoelectric properties, with an ultrahigh peak responsivity greater than 93 A W−1 and a detectivity of 2.5 × 1015 Jones, together with excellent reproducibility and stability. The maximum responsivities can be modulated by piezo–phototronic effect with an effective enhancement ratio of 480%. This work will open up a new route of designing MHP ferroelectric films for high‐performance PDs and offers the opportunity to utilize it for various optoelectronics applications. High‐quality 2D ferroelectric perovskite films with mixed spacer cations (BA+ and BDA2+) are prepared for self‐powered photodetectors (PDs). The self‐powered ultraviolet (UV) PDs exhibit excellent photoelectric properties, together with excellent reproducibility and stability. After applying pressures to the PD, the maximum responsivities can be modulated by the piezo–phototronic effect with an effective enhancement ratio of 480%.