Impacts of the Electron Transport Layer Surface Reconstruction on the Buried Interface in Perovskite Optoelectronic Devices

Abstract

Using density functional theory combined with ab initio molecular dynamics, we comprehensively investigated the performance enhancement mechanism of the device after surface reconstruction by passivating different halogen groups (i.e., F or Cl) at the ETL/perovskite interface. We demonstrated that the halogen group at the ETL layer could stabilize the geometric structure of the perovskite surface by balancing the interfacial interaction, ionic migration, and lead iodide framework. Even though halogen passivation decreased and increased the interface charge transfer at the O- and SnO-terminated MAPbI3/SnO2 interfaces, respectively, halogen passivation optimized surface reconstruction and could theoretically relieve the interface carrier recombination according to the changes in conduction band offsets generated by halogen passivation. Furthermore, the interfacial carrier recombination of the MAPbI3/SnO2 interface was also connected to the interfacial gap states, which were smaller for O-terminated MAPbI3/SnO2 interfaces with halogen passivation-induced surface reconstruction but larger for the SnO-terminated cases. Hence, our findings have implications for the design of buried interface optimization in perovskite optoelectronic devices.

Electrical transport properties of TiO2/MAPbI3 and SnO2/MAPbI3 heterojunction interfaces under high pressure

“…32,33 Most of the electron transport exists between the Pb-I framework and TiO 2 , and MA atomic groups basically do not participate in the electron transport between the interfaces. [34][35][36] Ti forms a chemical bond with I in MAPbI 3 , and electrons are transported from the surface of MAPbI 3 to TiO 2 . [37][38][39][40] The Fermi energy level is at the top of the valence band, and the right side of the Fermi energy level, which is the bottom CBM of SnO 2 , is basically composed of the valence electrons of Sn atoms, while the bottom CBM of MAPbI 3 is mainly the valence electrons of Pb atoms, as shown in Fig.…”

A study on theoretical models for investigating time-resolved photoluminescence in halide perovskites

“…Moreover, in halide perovskite-based devices, the electron/hole transport layers (TLs) are important components and the TRPL characterization is helpful to evaluate the layer information, i.e., surface/interface impurities and charge carrier transport rate between different layers. [41][42][43] 3. Exponential based models…”