In Situ Solution-Grown Halide Perovskite Single Crystals with Epitaxial Heterojunction Structures for Efficient Photodetection

In comparison with monocomponent perovskite single crystals, the heterojunctions of perovskite single crystals provide great chances to tune the optoelectronic properties. In this work, we develop an in situ solution growth approach to fabricate perovskite single-crystal heterojunctions with different compositions, which are MAPbCl(3)@MAPbBr(3), CsPbBr3 pMAPbBr(3), and CsPbBr3@MAPbCl(3). It was found that the as-formed gradient interface with mixed halogen components plays an important role in releasing the lattice mismatch for the in situ growth. Benefiting from the quasi-type II-like energy level alignment between MAPbCl(3) and MAPbBr(3) single-crystal counterparts, the heterojunction-based device exhibited an enhanced responsivity of 0.28 mA/W and a specific detectivity of over 10(9) Jones under the photovoltaic working mode even with a 1 mm electrode distance. This work provides a facile route to fabricate functional perovskite single crystals with rational design for photodetection applications.

Automated summary

Perovskite single-crystal heterojunctions provide opportunities to adjust the optoelectronic properties. In this work, perovskite single-crystal heterojunctions with different compositions were successfully fabricated using an in situ solution growth approach. The gradient interface played a crucial role in releasing the lattice mismatch. The heterojunction-based device exhibited enhanced performance due to the quasi-type II-like energy level alignment.