Bandgap Modulation in Efficient n‐Thiophene Absorbers for Dye Solar Cell Sensitization

Abstract

Five new sensitizers for dye sensitized solar cells have been designed consisting of conjugated thienylenevinylene units threaded with alkyl chains to improve solubility and cyanoacetic acid as anchoring group. The conjugation length was increased from 2 to 6 thienylenevinylene units, which resulted in a red-shift of the optical absorption of the dyes from 550 to 750 nm, improving the spectral overlap with the solar spectrum. The photovoltaic performance of these dyes as sensitizers in mesoporous TiO(2) solar cells shows a clear correlation of increasing photocurrent with the extension of the conjugation up to an optimal length. Further extension of the conjugation increases the absorption but additional effects like self-quenching or recombination processes reduce the photocurrent and photovoltages and consequently the overall efficiency of the DSC.

Nanoscale Interaction Between CdSe or CdTe Nanocrystals and Molecular Dyes Fostering or Hindering Directional Charge Separation

“…A number of previous studies have explored the interaction between semiconductor NCs and dyes in both energy4, 10 and charge transfer 11–13. We have systematically studied the interaction between CdSe or CdTe NCs and four different dyes, namely three Ru dyes, N3, N719, and black dye (BD), the most commonly used materials in dye‐sensitized solar cells,14 and a novel metal‐free organic dye, FL6 15. The molecular structures of these dyes and their absorption spectra in solution are shown in Supporting Information Figures S1 and S2a, respectively.…”

Organic Dyes with Well‐Defined Structures for Highly Efficient Dye‐Sensitised Solar Cells Based on a Cobalt Electrolyte

“…The longer p-bridgei nthe SGT-107 and SGT-108 dyes mayl ead to stronger p-p stacking on the TiO 2 surface, which would decrease the efficiency of electron injection. [18] The photovoltaic performances of the SGT-dye-sensitised DSSCs are summarised in Ta ble 2. Under standard global AM 1.5 solar conditions, the SGT-106-sensitised cell gave as hort-circuit photocurrent density (J sc )o f1 2.4 mA cm…”

Photocurrent enhancement in dye-sensitized photovoltaic devices with titania–graphene composite electrodes

“…The aim of IS measurements here is to identify variations in the devices concerning the changes of the rate of transport and recombination and also shift in the capacitance due to the presence of graphene that could strongly influence the performance [24]. Details about the methodology and the interpretation of IS results in connection to the performance of DSCs are provided in recent papers [25][26][27][28][29] The chemical capacitance and recombination resistance are plotted vs V F (Femi level voltage), that corresponds to remove from the bias voltage the effect of ohmic drops in the solar cell. IS enables extracting the voltage drop in the sensitized electrode, V F , at each applied potential, V app , by subtracting the effect of the series resistance on both R rec and C l as follows: V F = V app À V s À V ce , where V s and V ce are potential drops at the series resistance and at the counter-electrode, respectively.…”