Abstract
A promising way to advance perovskite solar cells is to improve the quality of the electron transport material-e.g., titanium dioxide (TiO2)-in a direction that increases electron transport and extraction. Although dense TiO2 films are easily grown in solution, efficient electron extraction suffers due to a lack of interfacial contact area with the perovskites. Conversely, mesoporous films do offer high surface-area-to-volume ratios, thereby promoting efficient electron extraction, but their morphology is relatively difficult to control via conventional solution synthesis methods. Here, a pulsed laser deposition method was used to assemble TiO2 nanoparticles into TiO2 hierarchical architectures exhibiting an anatase crystal structure, and prototype solar cells employing these structures yielded power conversion efficiencies of ∼14%. Our approach demonstrates a way to grow high aspect-ratio TiO2 nanostructures for improved interfacial contact between TiO2 and perovskite materials, leading to high electron-hole pair separation and electron extraction efficiencies for superior photovoltaic performance. Compared to previous pulsed laser deposition-synthesized TiO2 mesoporous crystalline networks that needed post-thermal annealing at 500 °C to form mesoporous crystalline networks, our relatively low temperature (300 °C) TiO2 processing method may promote reduced energy-consumption during device fabrication, as well as enable compatibility with flexible polymer substrates such as polyimide.
Original language | English |
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Pages (from-to) | 27067-27072 |
Number of pages | 6 |
Journal | Physical Chemistry Chemical Physics |
Volume | 18 |
Issue number | 39 |
DOIs | |
State | Published - 2016 |
Funding
Synthesis of TiO2 nanostructures sponsored by the Materials Science and Engineering Division, Office of Basic Energy Sciences, U.S. Department of Energy. Photovoltaic device fabrication and characterization were conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. We thank Dale Hensley for the assistance in acquiring EDS maps.