Enhancing the performance of dye-sensitized solar cells: doping SnO₂photoanodes with Al to simultaneously improve conduction band and electron lifetime

Abstract

ARTICLE This journal isAmong the semiconductor materials used in dye-sensitized solar cells (DSSCs), SnO 2 is an important alternative material to TiO 2 used in photoanode. In this work, SnO 2 and Al-doped SnO 2 nanocrystals were prepared via a simple hydrothermal method, and we found both key dual-factors, such as tuning the conduction band and suppressing the charge recombination, are synchronously improved in the Al-doped samples for the first time. The electron lifetime is significantly improved and the conduction band edge is shifted negatively by the Al-doping in SnO 2 photoanode. Compared to the undoped SnO 2 DSSCs (AM 1.5, 100 mW cm -2 ), the power conversion efficiency (η) of the optimized Al-doped SnO 2 DSSCs is enhanced by 75%. After being treated with TiCl 4 , the highest η of DSSCs based on Al-doped SnO 2 nanocrystals is approximately 6.91%, which is a high overall photo conversion efficiency for SnO 2 based DSSCs. ExperimentalMaterials contributed equally to this work.Electronic Supplementary Information (ESI) available: IPCE of the fabricated DSSCs with SnO2, Sn0.98Al0.02O2, and Sn0.98Al0.02O2/TiCl4 as photoanodes. EIS spectra of the SnO2 and the Al-doped SnO2 DSSCs. Comparison for the photovoltaic performance of the DSSCs based on different SnO2 photoanode structures. See

Efficient charge collection of photoanodes and light absorption of photosensitizers: A review

“…Researches were carried out on doped SnO 2 using variable metals such as Zn, 37,66 Al, 67,68 and Ga. 69 69 who found that the highest efficiency of about 7.11% could be obtained after the post treatment with TiCl 4, which is greater than their own previous work. 67 Finally, it became apparent that SnO 2 by the same token of TiO 2 shows enhanced PCE by the tuning of bandgap and reducing the charge recombination. As moving through the papers based on doping on SnO 2 photoanodes, some common features were observed such as (a) hydrothermal method was commonly used for the synthesize of all the doped SnO 2 materials and (b) they blocks the interfacial charge recombination as well as shows a negative shift to the CB of SnO 2 .…”

“…In contrast to doped TiO 2 photoanodes, doped ZnO and SnO 2 photoanodes are very rare. Researches were carried out on doped SnO 2 using variable metals such as Zn, 37,66 Al, 67,68 and Ga 69 . Both Dou et al and Li et al have investigated the effect of Zn doping in SnO 2 photoanodes.…”

Aluminum-Doped SnO2Hollow Microspheres as Photoanode Materials for Dye-Sensitized Solar Cells

“…It is an efficient way to inhibit these back reactions by doping SnO 2 with other metal elements. Duan et al doped SnO 2 nanoparticle with Al and found the tuning of the conduction band and suppression of charge recombination [6]. Li et al…”

Enhanced photovoltaic properties in dye sensitized solar cells by surface treatment of SnO2 photoanodes

“…The wider bandgap of SnO 2 , compared to anatase TiO 2 (3.2 eV) creates fewer oxidative holes in the valence band under UV illumination, so as to minimize dye degradation rate and long term stability of DSSCs 16 17 . Because of these appealing properties, SnO 2 has been recently utilized in other advanced applications 18 19 20 , including hydrogen gas sensing 21 22 . Various synthesis techniques of SnO 2 nanocomposites have also been reported in recent literature 23 24 .…”