Growth behaviors and emission properties of Co-deposited MAPbI3 ultrathin films on MoS₂

Abstract

Hybrid organic–inorganic perovskite (PVK) thin films have obtained much attention in the optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide (MAPbI3) ultrathin films via co-deposition of PbI2 and CH3NH3I (MAI) on chemical vapor deposition (CVD)-grown monolayer MoS2 as well as the corresponding photoluminescence (PL) properties at different growing stages. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements reveal the MoS2 tuned growth of MAPbI3 in a Stranski-Krastanov mode. PL and Kelvin probe force microscopy (KPFM) results confirm that MAPbI3/MoS2 heterostructures have a Type-II energy level alignment at the interface. Temperature-dependent PL measurements on layered MAPbI3 (at the initial stage) and on MAPbI3 crystals in averaged size of 500 nm (at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI3/transition-metal dichalcogenide (TMDC)-based innovative devices for wider optoelectronic applications.

Perovskite Multiple Quantum Well Superlattices: Potentials and Challenges

“…Ultrathin MAPbI 3 thermal evaporation has been demonstrated, indicating its potential for MQWs. 20,21 To date, only five works have demonstrated evaporated perovskite MQWs, all based on CsPbBr 3 wells and three organic barriers. 22−26 We note that MQWs with different constituent combinations, such as perovskite barriers and low-band-gap material wells or perovskites with different band gaps acting as wells and barriers, have not been explored and hold high potential for novel optoelectronic properties.…”