Epitaxy of a Monocrystalline CsPbBr 3 -SrTiO 3 Halide-Oxide Perovskite p-n Heterojunction with High Stability for Photodetection

• Published in: Advanced materials (Weinheim) 2023-08, Vol.35 (31), p.e2303544
• Main Authors: Liu, Songlong, Chen, Yang, Gao, Weiqi, Li, Wanying, Yang, Xiaokun, Li, Zhiwei, Xiao, Zhaojing, Liu, Yuan, Wang, Yiliu
• Format: Article
• Language: English
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202303544

Perovskite heterojunctions are essential components of perovskite optoelectronics, but their construction and investigation have been impeded by the instability and severe anion interdiffusion. This work epitaxially deposits p-type CsPbBr on n-type Nb:SrTiO (STO) to construct a functional perovskite heterojunction with high stability. The lattice match allows epitaxial growth of CsPbBr to occur over large scale, resulting in a monocrystalline thin film with excellent crystallinity and uniformity. The highly stable STO prevents the anion migration frequently happening in halide perovskites, forming a sharp interface of two perovskite with opposite conduction type, with which a diode is fabricated and a current rectification ratio of 374 is obtained. The diode is able to work as a photodetector with dark current of 2.01 × 10 A at -1 V and responsivity (R) of 8.26 A W , rendering a detectivity (D*) of 2.98 × 10 Jones. Owing to the all-inorganic architecture, effective photoresponse at temperature as high as 150 °C is guaranteed with D* of ≈1.52 × 10 Jones. Combining the unique optoelectrical properties of halide perovskite and the rigidity of oxide perovskite, the epitaxy of CsPbBr on n-type STO opens up a new method to construct functional perovskite heterojunction for optoelectronics.