Enhanced Efficiency and stability of Perovskite Solar Cells using Porous Hierarchical TiO2 Nanostructures of Scattered Distribution as Scaffold

• Published in: Electrochimica acta Vol. 236; pp. 351 - 358
• Main Authors: Hou, Xian, Pan, Likun, Huang, Sumei, Wei, Ou-Yang, Chen, Xiaohong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 10-05-2017; Elsevier BV
• Subjects: Electron transport; Energy conversion efficiency; Grains; mesoscopic; Metal-organic frameworks; Moisture resistance; Nanoscience; Nanostructure; Perovskite; perovskite solar cells; Photovoltaic cells; Porosity; porosity TiO2; Sintering; Solar cells; Stability; Titanium dioxide; Titanium oxides; Wettability; mesoscopic; porosity TiO2; perovskite solar cells; stability; metal-organic frameworks
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2017.03.192

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•Ordered porous hierarchical TiO2 (hier-TiO2) was synthesized by sintering MOFs.•The scaffold of scattered distribution was prepared by hier-TiO2 nanostructures.•The crystallization of perovskite was controlled due to ordered porous hier-TiO2.•Grains with enlarged sizes were formed due to scaffold of scattered distribution.•PSCs with hier-TiO2 scaffold show higher efficiency and better stability.
A type of quasi-mesoscopic perovskite solar cells (QM-PSCs) with porous hierarchical TiO2 (hier-TiO2) nanostructures of scattered distribution as scaffold was investigated. The porous hier-TiO2 nanostructures were synthesized by sintering MIL-125(Ti) of metal-organic frameworks (MOFs) at 500°C in air and which were partly inherited from the ordered porosity of MIL-125(Ti). The ordered hier-TiO2 nanostructures were scattered on compact TiO2 layer to form a quasi-mesoscopic scaffold of scattered distribution, which can offer enough growth space for perovskite grains and promote the ordered growth of perovskite grains. The QM-PSCs shows a power conversion efficiency (PCE) of 16.56%, much higher than PCE (11.38%) of PSCs with conventional small TiO2 nanoparticles (npt-TiO2) as scaffold and PCE (6.07%) of planar PSCs with compact TiO2 layer. The PCEs of PSCs with hier-TiO2 and npt-TiO2 remain 47% and 22% of the initial PCE values aging for 30days in air, indicating that PSCs with hier-TiO2 scaffold shown better stability and moisture resistance. The enhanced performance of QM-PSCs is primarily attributed to the superior wettability quasi-mesoscopic scaffold with ordered porous hier-TiO2 nanostructures, which help to form the high quality perovskite film with better crystillinity and less pin-holes, and improve the contact properties between perovksite and electron transport layer.