Carrier lifetime enhancement in halide perovskite via remote epitaxy

Abstract

Crystallographic dislocation has been well-known to be one of the major causes responsible for the unfavorable carrier dynamics in conventional semiconductor devices. Halide perovskite has exhibited promising applications in optoelectronic devices. However, how dislocation impacts its carrier dynamics in the ‘defects-tolerant’ halide perovskite is largely unknown. Here, via a remote epitaxy approach using polar substrates coated with graphene, we synthesize epitaxial halide perovskite with controlled dislocation density. First-principle calculations and molecular-dynamics simulations reveal weak film-substrate interaction and low density dislocation mechanism in remote epitaxy, respectively. High-resolution transmission electron microscopy, high-resolution atomic force microscopy and Cs-corrected scanning transmission electron microscopy unveil the lattice/atomic and dislocation structure of the remote epitaxial film. The controlling of dislocation density enables the unveiling of the dislocation-carrier dynamic relation in halide perovskite. The study provides an avenue to develop free-standing halide perovskite film with low dislocation density and improved carried dynamics.

Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite

“…For the former, typical transparent oxide substrates and other charge transporting bottom contact layers used for devices cannot direct the growth of the perovskite film. Single crystalline chunks of halide perovskites and epitaxially grown thin films on single crystal substrate have been demonstrated [7][8][9][10][11] , but thicknesscontrolled layer transfer of the grown materials onto a desired substrate has not been successful. For the latter, inherently fast reaction kinetics during the typical solution process causes numerous nuclei to form in the bulk solution, resulting in the growth of randomly oriented fine grains with a high density of defects.…”

Enhanced Performance of Planar Perovskite Solar Cells Induced by Van Der Waals Epitaxial Growth of Mixed Perovskite Films on WS2 Flakes

“…Epitaxial growth has been demonstrated to be an effective technique for preparing high‐quality semiconductor films with preferred orientations. [ 14–16 ] Epitaxial growth of perovskite films have been studied by several groups. For example, Wang et al.…”

Epitaxial Metal Halide Perovskites by Inkjet‐Printing on Various Substrates

“…While epitaxy from vapors is standard for conventional inorganic semiconductors such as silicon, germanium, or III/V compounds, [ 22–26 ] it has been recently also obtained for MHPs. [ 27,28 ] Chemical vapor deposition of CH 3 NH 3 PbCl 3 on mica substrates [ 29 ] and CsPbBr 3 on SrTiO 3 [ 30 ] was successfully shown, as well as molecular beam epitaxy of CsSnBr 3 on NaCl substrates. [ 27 ] Coherent and continuous films were demonstrated in an interesting attempt called “remote epitaxy,” using polar substrates coated with graphene, to obtain epitaxial halide perovskite films with improved carrier lifetimes.…”

“…[ 27 ] Coherent and continuous films were demonstrated in an interesting attempt called “remote epitaxy,” using polar substrates coated with graphene, to obtain epitaxial halide perovskite films with improved carrier lifetimes. [ 28 ] A special feature of the metal‐halide‐perovskite is that they allow processing from solutions. Therefore, the spin coating was introduced to obtain in particular CH 3 NH 3 PbI 3 crystallites on KCl substrates, exhibiting superior light detectivity as compared to any other crystalline or a polycrystalline structure from the same material.…”