Seung Hyeon Jo1,Tae-Woo Lee1,2
Seoul National University1,Research Institute of Advanced Materials, Seoul National University2
Seung Hyeon Jo1,Tae-Woo Lee1,2
Seoul National University1,Research Institute of Advanced Materials, Seoul National University2
Metal halide perovskites (MHPs) are promising materials for active layers in solar cells (SCs) because they have outstanding advantages such as low exciton binding energy (~14 meV for CH(NH<sub>2</sub>)<sub>2</sub>PbI<sub>3</sub>)<sup>[1]</sup> and high carrier mobility (100 cm<sup>2</sup>/(Vs))<sup>[2]</sup>. Despite the superior properties of MHPs, MHP polycrystalline (PC) bulk film based SCs had bad reproducibility due to bad surface morphology of MHP PC films. Furthermore, controlling the surface morphology of MHP PC films is very difficult because the environmental conditions such as temperature and moisture have a strong influence on the morphology. Here, we present mixed-cation MHP nanoparticles (NPs) synthesized by hot injection method and purified with ligand-engineering method. Moreover, perovskite NP layers with uniform morphology were fabricated by using a ligand washing method. The ligand engineering methods which reduce the amount of ligand improved the charge extraction/transport characteristics in MHP NP films. Also, the morphology of perovskite film was enhanced by using mixed-cation perovskite nanoparticles. Our research suggests a promising way to increase PCE of perovskite NP SCs.<br/>[1] K. Galkowski et al., <i>Energy Environ. Sci.</i>, 2016, 9, 962.<br/>[2] L. M. Herz, <i>ACS Energy Lett.</i>, 2017, 2, 1539-1548.