Templated growth of oriented layered hybrid perovskites on 3D-like perovskites

Jifei Wang,Gang Chen,Ke Meng,Jun He,Shiqiang Luo,Zhimin Li,Yehao Deng,Yifu Chen,Si Xiao,Conghua Zhou,Jinsong Huang,Han Huang,Yun Lin,Yongbo Yuan,Tiantian Huang,Liming Ding

doi:10.1038/s41467-019-13856-1

Abstract

The manipulation of crystal orientation from the thermodynamic equilibrium states is desired in layered hybrid perovskite films to direct charge transport and enhance the perovskite devices performance. Here we report a templated growth mechanism of layered perovskites from 3D-like perovskites which can be a general design rule to align layered perovskites along the out-of-plane direction in films made by both spin-coating and scalable blading process. The method involves suppressing the nucleation of both layered and 3D perovskites inside the perovskite solution using additional ammonium halide salts, which forces the film formation starts from solution surface. The fast drying of solvent at liquid surface leaves 3D-like perovskites which surprisingly templates the growth of layered perovskites, enabled by the periodic corner-sharing octahedra networks on the surface of 3D-like perovskites. This discovery provides deep insights into the nucleation behavior of octahedra-array-based perovskite materials, representing a general strategy to manipulate the orientation of layered perovskites.

Highlights

The manipulation of crystal orientation from the thermodynamic equilibrium states is desired in layered hybrid perovskite films to direct charge transport and enhance the perovskite devices performance
Layered perovskites are highly electrically anisotropic, because the charge transport along out of plane (OP) direction is much hindered by the low-conducting organic spacing layers[7,8]
For the butylamine (BA) based RP perovskites, the BA-terminated planes have the lowest surface energy, which lead to in-plane orientation (IP) of this layered perovskite on many commonly used substrates to minimize the interface energy in the material system[7,13]

Summary

Region B

Spin-coated film (Supplementary Fig. 10) until heated at elevated temperature of 70~100 °C29. The much reduced homogenous nucleation of PDS inside solution makes the precipitation of PDS at the top of the liquid phase dominating. This is because the evaporation of DMF near the liquid surface is rapid during high-speed spin coating. Since the preformed PDS are much suppressed by NH4Cl additives, these residual solvated phases may not be necessarily detectable by XRD (Supplementary Fig. 10).

Downward growth

Narrow nucleating region

Author contributions

Findings

Additional information