Effect of nature of anchoring groups on photosensitization behavior in unsymmetrical squaraine dyes

Shivashimpi, Gururaj M.; Pandey, Shyam S.; Watanabe, Rie; Fujikawa, Naotaka; Ogomi, Yuhei; Yamaguchi, Yoshihiro; Hayase, Shuzi

doi:10.1016/j.jphotochem.2013.09.004

Cited by 20 publications

(8 citation statements)

References 33 publications

(34 reference statements)

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“…Moreover, starting from para ‐substituted hydrazines, it is possible to obtain indolenines with different groups in the 5‐position. For example, bromine can be exploited for coupling reactions such as Buchwald–Hartwig or Suzuki for diarylamine45 or heteroaryl substitutions,46 respectively, whereas cyano groups can be reduced to aldehydes and then modified through a Knoevenagel reaction, leading to cyanoacetic derivatives 47…”

Section: Polymethine Dyesmentioning

confidence: 99%

“…In fact, the cyanoacetic anchoring moiety is more electron‐withdrawing and longer π‐spaced than COOH. Hayase and co‐workers further investigated in 2014 the possibility of enhancing the π‐bridge47 [S19,20] adding a thiophene between the anchoring moiety and the indolenine (SQ‐B and SQ‐C in Figure 21). Unfortunately, the presence of thiophene lowered the overall cell performance.…”

Section: Structure–property Relationshipsmentioning

confidence: 99%

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Polymethine Dyes in Hybrid Photovoltaics: Structure–Properties Relationships

et al. 2016

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Polymethine dyes as photosensitizers for dye‐sensitized solar cells (DSCs) are reviewed. The review provides a summary of design strategies, the main synthetic routes, and the optical and photovoltaic properties of polymethine dyes applied in hybrid photovoltaics. In particular, we focus on cyanine and squaraine dyes and their structure–properties relationships, highlighting the role of the active molecule design on device performance.

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Section: Polymethine Dyesmentioning

confidence: 99%

Section: Structure–property Relationshipsmentioning

confidence: 99%

Polymethine Dyes in Hybrid Photovoltaics: Structure–Properties Relationships

et al. 2016

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“…It is interesting to note that the monomeric D sq dye showed the device efficiency of 1.6 % ( V oc 0.54 V, J sc 4.2 mA/cm 2 , ff 71.5 %) under the similar experimental condition. Though the structural backbone of monomeric dye ( D sq ) is similar to reported YR6 dye, the device performance have been changed significantly in the presence of different alkyl groups . The V oc obtained for the devices were in the order of D sq (0.52 V)< D sq ‐D sq (0.54 V)< D 1 ‐D sq (0.64 V), in the absence of CDCA.…”

Section: Resultsmentioning

confidence: 79%

Homo‐ and Heterodimeric Dyes for Dye‐Sensitized Solar Cells: Panchromatic Light Absorption and Modulated Open Circuit Potential

et al. 2018

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The design of dyes for panchromatic light absorption has attracted much attention in the field of dye‐sensitized solar cells (DSSCs). An approach to enhance panchromatic light absorption utilizes mixtures of complementary light‐absorbing dyes as well as dyes with specific anchoring groups that facilitate interfacial charge transfer with TiO2. Dipole‐dipole interactions between the dye molecules on the surface broaden the spectrum, which results in decreased DSSC device performance. However, controlled aggregation of dyes results in broadening the spectral profile along with enhanced photocurrent generation. To control the dye‐dye interaction, dimeric dyes with different dipole lengths D1‐Dsq, Dsq‐Dsqwere systematically designed and synthesized. The photophysical and electrochemical properties were evaluated and the EHOMO and ELUMO levels were determined; these energy levels determines the electron injection from ELUMO of the dye to ECB of TiO2 and regeneration of oxidized dye by the electrolyte, respectively. The absorption spectra of Dsq‐Dsq, D1‐Dsq were broadened in solution compared to model dye Dsq; this indicates that the dye‐dye interaction is prominent in solution. In D1‐Dsq excitation energy transfer between photoexcited D1 and Dsq was explained by using Förster resonance energy transfer (FRET). The homodimeric dye showed a device performace of 2.8 % (Voc 0.607, Jsc 6.62 mA/cm2, ff 69.3 %),whereas the heterodimeric dye D1‐Dsq showed a device performance of 3.9 % (Voc 0.652 V, Jsc 8.89 mA/cm2, ff 68.8 %). The increased photocurrent for D1‐Dsqis due to the panchromatic IPCE response compared to Dsq‐Dsq. The increased Vocis due to the effective passivation of the TiO2 surface by the spirolinker, and the effective dipole moment that shifts the conduction band on TiO2. Hence, the open circuit potential, Voc, for the devices prepared from Dsq, D1‐Dsq and Dsq‐Dsqwere systematically modulated by controlling the intermolecular π‐π and intramolecular dipole‐dipole interactions of the dimeric dyes.

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“…[21][22][23] 1,2,3,3-Tetramethyl-3H-indolium iodide, a well-known synthetic agent of many fluorescent dyes, is considered to contain an activated methyl group which can react with an aldehyde or carbonyl group. 24,25 In our previous research, the activated C-2 methyl group reacted with molecular iodine to form an aldehyde via Kornblum oxidation in the presence of dimethyl sulfoxide (DMSO). 26 Based on these results, we report an I 2 -promoted one-pot method for the synthesis of indolin-2-ones under metal-free conditions.…”

Section: Introductionmentioning

confidence: 99%