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

Perovskite heterojunctions are essential components of perovskite optoelectronics, but their construction and investigation have been impeded by the instability and severe anion interdiffusion. Here we epitaxially deposited p-type CsPbBr 3 on n-type Nb: SrTiO 3 (STO) to construct a functional perovskite heterojunction with high stability. The lattice match allowed the epitaxial growth of CsPbBr 3 to occur over large scale, resulting in a monocrystalline thin film with excellent crystallinity and uniformity. The highly stable STO prevented the anion migration frequently happening in halide perovskites, forming a sharp interface of two perovskite with opposite conduction type, with which a diode was fabricated and a current rectification ratio of 374 was obtained. The diode is able to work as a photodiode-type photodetector with low dark current of 2.01 × 10 -12 A at -1 V and high responsivity (R) of 8.26 A/W, rendering a detectivity (D*) of 2.98 × 10 13 Jones. Owing to the all-inorganic architecture, effective photodetection at temperature as high as 150 °C was guaranteed with D* of ∼1.52 × 10 13 Jones. Combining the unique optoelectrical properties of halide perovskite and the rigidity of oxide perovskite, the epitaxy of CsPbBr 3 on Nb: STO opened up a new method to construct functional perovskite heterojunction for optoelectronics. This article is protected by copyright. All rights reserved.