Interface optoelectrical dynamic in 2D perovskite/InSe heterostructure

Van der Waals (vdW) heterostructure composed of two-dimensional (2D) materials and 2D perovskite has shown excellent optoelectrical properties recently, while the interfacial coupling is less investigated. Here, van der Waals InSe/(C 4 H 9 NH 3 ) 2 (CH 3 NH 3 )Pb 2 I 7 heterostructure is fabricated and systemically investigated by photoluminescence (PL) spectroscopy. An optical broadband emission is generated due to the formation of heterostructure. The first principle calculation and variable PL spectra suggest the dynamic generation of defects such as iodine vacancy and charge states. Electron - phonon coupling of the 2D perovskite is weakened from -127 meV to -90 meV in the heterostructure. The band offset causes the built-in electrical field, which strengthens the optoelectrical response of heterostructure devices. The results deepen the understanding of the interfacial optoelectrical dynamic of 2D perovskite-related vdW heterostructure and help develop superior optoelectrical vdW heterostructure devices.