Lithium Incorporation into TiO₂ Photoanode for Performance Enhancement of Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSCs) are one of the most favorable solar cell technologies owing to their low cost and ease of fabrication. The electron transport layer, consisting of a mesoporous titanium oxide (TiO 2 ) photoanode, plays a crucial role in DSSCs. In this study, we performed a post-lithium (Li) treatment on TiO 2 films to enhance the optoelectronic features and power conversion efficiency (PCE) of DSSCs. The material properties of pristine and Li-treated TiO 2 films were examined by X-ray diffraction (XRD), atomic force microscopy (AFM), steady-state photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS). Li treatment was confirmed to suppress defects and enhance the crystallinity of the TiO 2 films. Furthermore, TiO 2 films sensitized with N719 dye were used as photoanodes and Pt as a counter electrode for the fabrication of DSSCs. The devices with 0.1 M Li-TFSI treatment showed a performance improvement of ∼20%, with a PCE of 10.5%, while the control DSSC had a PCE of 8.7%. The device performance was significantly enhanced owing to improved structural properties, efficient charge transport, and suppression of recombination owing to the passivation of trap states.

Amphiphilic Graft Copolymers as Templates for the Generation of Binary Metal Oxide Mesoporous Interfacial Layers for Solid-State Photovoltaic Cells

“…The ideal photoanode has a large surface area, high dye absorption, fast electron transfer rate, and suppressed electron recombination. TiO 2 [ 3 , 4 , 5 , 6 , 7 , 8 ], SnO 2 [ 9 , 10 , 11 , 12 , 13 ], and ZnO [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] are used as photoanodes. In general, TiO 2 is used as a photoanode because it has an appropriate energy band gap, a large specific surface area, stable dye adsorption, and acts as a scattering layer leading to enhanced light harvesting.…”

Amphiphilic Graft Copolymers as Templates for the Generation of Binary Metal Oxide Mesoporous Interfacial Layers for Solid State Photovoltaic Cells

“…The ideal photoanode has a large surface area, high dye absorption, fast electron transfer rate, and suppressed electron recombination. TiO 2 [3][4][5][6][7][8], SnO 2 [9][10][11][12][13], and ZnO [14][15][16][17][18][19][20][21][22][23][24][25][26][27] are used as photoanodes. In general, TiO 2 is used as a photoanode because it has an appropriate energy band gap, a large specific surface area, stable dye adsorption, and acts as a scattering layer leading to enhanced light harvesting.…”