Aggregation-Free ZnO Nanocrystals Coupled HMP-2 Dye of Higher Extinction Coefficient for Enhancing Energy Conversion Efficiency

Abstract

A novel and highly efficient dye, Ru(H 2 dcbpy)(4-(4-(N,N-di(p-hexyloxyphenyl)amino)styryl)-4′-methyl-2,2′bipyridine)(NCS) 2 , HMP-2, with extinction coefficients of about 33 260 L • mol -1 • cm -1 at 534 nm and about 20 000 L • mol -1 • cm -1 at 490 nm, is designed and further applied onto ZnO nanocrystals for dye-sensitized solar cells application. ZnO nanocrystals of a few nanometers are spin coated onto an indium-tin oxide substrate for forming about 2.5 µm uniform film thickness. Change in the surface appearance of ZnO in the presence of N3 and in newly designed HMP-2 dye is illustrated. Structural elucidation of the newly developed HMP-2 dye is presented in depth. A ZnO nanoparticle electrode is dipped in HMP-2 dye and in commercially used N3 dyes for 24 h to see the influence of dye structure on the surface aggregation effect due to insulating Zn + /dye complex layer formation. Interestingly, the ZnO nanocrystal electrode surface with HMP-2 dye is almost free of this efficiency-diminishing effect, and a solar-to-electrical conversion efficiency of 4.03%, which is about 40-fold times higher than that of N3 dye, is obtained.

Regioisomeric Effects on the Electronic Features of Indenothiophene‐Bridged D–π‐A′–A DSSC Sensitizers

“…The donor group, that is, the di(p-hexyloxyphenyl)amino group, was introduced to the phenylene ring of the IDT compound 2 through a Buchwald-Hartwig cross-coupling reaction. [30] Then, the IDT derivative 3 was converted into the stannyl intermediate, which was subject to a selective Stillecoupling reaction [18] with 5-bromo-2-iodopyrimidine, affording the bromo compound 4. A bromo-lithium exchange reaction conducted on compound 4 at À100 8C gave the lithiated intermediate, which was quenched with ethyl formate [31] to give the carbaldehyde compound 5.…”

Effects of tethering alkyl chains for amphiphilic ruthenium complex dyes on their adsorption to titanium oxide and photovoltaic properties

“…By using ruthenium complex dye-sensitized mosoporous TiO 2 , the solar cells with power conversion efficiency up to 11% have been achieved [2]. In order to pursue better photovoltaic performance, various structural modifications to the bipyridyl ruthenium dye have been attempted [13][14][15][16][17][18][19][20][21][22]. For example, tethering conjugate moieties [13][14][15][16][17][18] on the bipyridyl ligands increased the light absorption, tethering hydrophobic aliphatic long chains [19] and cross-linkable side chains [20,21] prolonged the service life, and tethering triethylene oxide methyl ether groups brought in the cation coordinating properties for the dye to enhance the photocurrent [22].…”

Facile construction of nanofibrous ZnO photoelectrode for dye-sensitized solar cell applications

“…This is due to the poor chemical stability of ZnO in acidic dye solution and the formation of Zn 2+ /dye complexes that could block the injection of electrons from the dye molecules to the semiconducting electrodes. 5,6 To improve the performance of ZnO-based DSSCs, one strategy is to design new dyes that are suitable for ZnO photoelectrode, 7 and the other is to develop ZnO photoelectrode with new architectures. In this context, onedimensional ͑1D͒ ZnO nanostructures have attracted great interest recently because they could provide a direct conduction pathway for rapid collection of photoelectrons.…”