Aggregation of ZnO Nanocrystallites for High Conversion Efficiency in Dye‐Sensitized Solar Cells

Abstract

Here comes the sun: A conversion efficiency as high as 5.4 % has been achieved on dye‐sensitized ZnO solar cells with photoelectrode films consisting of polydisperse aggregates, compared to 2.4 % for the films with only nanosized crystallites. The aggregation of nanocrystallites with a broad size distribution is effective in enhancing the light‐harvesting efficiency by inducing light scattering within the photoelectrode films.

Photoelectrochemical performance of DSSC with monodisperse and polydisperse ZnO SPs

“…2 exhibit a complex relation as a function of PDI, as indicated by fairly high IPCE value of SP2 and SP4 monolayers. In view of PDI, these results are somewhat contradictory to earlier findings [12], since polydisperse aggregates are believed to improve the photocurrent action. Further study is needed to confirm these results, particularly on the distribution characteristics and the nanocrystallites size.…”

“…Similar instability and reactivity issues have been reported previously [12,14]. Performance degradation of DSSC was reported to take place with increasing dye loading time [12] or dye concentration [14,15], either resulting in dissolution of ZnO SPs [12] or formation of aggregates consisting Ru-based dye and Zn 2+ [14,15] leading to a reduction in the potential between ZnO surface and the counter electrode. Other research [16] suggests that dye sensitization times must be varied with the photoanode thickness otherwise it will lead to significant deterioration in the performance for longer loading time.…”

“…Other research [16] suggests that dye sensitization times must be varied with the photoanode thickness otherwise it will lead to significant deterioration in the performance for longer loading time. According to [12], the sensitizing time should have been strictly controlled and limited for DSSCs fabrication. Control of sensitizing time is intended to avoid the dissolution of Zn surface and the formation of Zn 2+ with dye complexes that might block the electron transport from the dye to ZnO layer.…”

Porous Titania Nanosheet/Nanoparticle Hybrids as Photoanodes for Dye-Sensitized Solar Cells

“…[2][3][4][5][6][7] One of major drawbacks of the conventional TiO2 nanoparticle photoanodes in DSSCs is the negligible light scattering of the films due to their small particle size ranging typically from ca. 20~30 nm, resulting in a low light harvesting efficiency.…”

Mass Synthesis in Polyol of Tailored Zinc Oxide Nanoparticles for Photovoltaic Applications

“…In addition, the zinc oxide occurs in a very rich variety of structures and offers a wide range of specific surface area necessary to adsorb organic dye molecules. ZnO can be easily grown as nanostructured films and various nanostructures have been described in the literature [12]- [19]. In addition, the synthesis of highly crystalline ZnO layers at low temperature has been performed by several techniques compatible with substrates that do not tolerate heat treatments.…”