title: Tailoring the Mesoscopic TiO2Layer: Concomitant Parameters for Enabling High-Performance Perovskite Solar Cells.
abstract: Architectural control over the mesoporous TiO2film, a common electron-transport layer for organic-inorganic hybrid perovskite solar cells, is conducted by employing sub-micron sized polystyrene beads as sacrificial template. Such tailored TiO2layer is shown to induce asymmetric enhancement of light absorption notably in the long-wavelength region with red-shifted absorption onset of perovskite, leading to ~20% increase of photocurrent and ~10% increase of power conversion efficiency. This enhancement is likely to be originated from the enlarged CH3NH3PbI3(Cl) grains residing in the sub-micron pores rather than from the effect of reduced perovskite-TiO2interfacial area, which is supported from optical bandgap change, haze transmission of incident light, and one-diode model parameters correlated with the internal surface area of microporous TiO2layers. With the templating strategy suggested, the necessity of proper hole-blocking method is discussed to prevent any direct contact of the large perovskite grains infiltrated into the intended pores of TiO2scaffold, further mitigating the interfacial recombination and leading to ~20% improvement in power conversion efficiency compared with the control device using conventional solution-processed hole blocking TiO2. Thereby, the imperatives that originate from the structural engineering of the electron-transport layer are discussed to understand the governing elements for the improved device performance.
authors.affiliation: Department of Materials Science and Engineering, WCU Hybrid Materials Program, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea.
authors.forename: Taehyun
authors.initials: T
authors.lastname: Hwang
authors.affiliation: Department of Materials Science and Engineering, WCU Hybrid Materials Program, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea.
authors.forename: Sangheon
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, WCU Hybrid Materials Program, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea.
authors.forename: Jinhyun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, WCU Hybrid Materials Program, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea.
authors.forename: Jaewon
authors.initials: J
authors.lastname: Kim
authors.affiliation: School of Materials Science and Engineering, Chungnam National University, Daejeon, 34134, Korea.
authors.forename: Chunjoong
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea.
authors.forename: Byungha
authors.initials: B
authors.lastname: Shin
authors.affiliation: Department of Materials Science and Engineering, WCU Hybrid Materials Program, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea. byungwoo@snu.ac.kr.
authors.forename: Byungwoo
authors.initials: B
authors.lastname: Park
keywords: Light management; Modeling; Nanostructural engineering; Perovskite solar cell; Shunting path