Tailoring the Mesoscopic TiO₂ Layer: Concomitant Parameters for Enabling High-Performance Perovskite Solar Cells

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• 作者：Taehyun Hwang ; Sangheon Lee ; Jinhyun Kim ; Jaewon Kim…
• 关键词：Perovskite solar cell ; Nanostructural engineering ; Light management ; Modeling ; Shunting path
• 刊名：Nanoscale Research Letters
• 出版年：2017
• 出版时间：December 2017
• 年：2017
• 卷：12
• 期：1
• 全文大小：1887KB
• 刊物主题：Nanotechnology; Nanotechnology and Microengineering; Nanoscale Science and Technology; Nanochemistry; Molecular Medicine;
• 出版者：Springer US
• ISSN：1556-276X
• 卷排序：12

文摘

Architectural control over the mesoporous TiO₂ film, 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 TiO₂ layer 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-TiO₂ interfacial 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 TiO₂ layers. 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 TiO₂ scaffold, 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.