Anders Hagfeldt

A light-resistant organic sensitizer for solar-cell applications.

Finely tuned: A stable dye-sensitized solar cell that contains a molecularly engineered organic dye has been prepared. The efficiency of the cell remains at 90% after 1000 h of light soaking at 60 degrees C. The remarkable stability of the cell is also reflected in the open-circuit voltage value (V(oc)), short-circuit photocurrent-density value (J(sc)), and the fill factor, which also show barely no decline (see picture).

Tuning of phenoxazine chromophores for efficient organic dye-sensitized solar cells

Through introducing an energy antenna system into a simple phenoxazine dye (TH301), a novel and efficient dye TH305 was designed and synthesized for application in a dye sensitized solar cell with prominent overall conversion efficiency of 7.7%.

Efficient near infrared D–π–A sensitizers with lateral anchoring group for dye-sensitized solar cells

A new strategy in which the anchoring group is separated from the acceptor groups of the dyes was developed; among these dyes, the HY103 dye gives a maximum IPCE value of 86% at 660 nm and an eta value of 3.7% in the NIR region reported in DSCs.

Tuning the HOMO energy levels of organic dyes for dye-sensitized solar cells based on Br-/Br3- electrolytes

A series of novel metal-free organic dyes TC301-TC310 with relatively high HOMO levels were synthesized and applied in dye-sensitized solar cells (DSCs) based on electrolytes that contain Br(-)/Br(3)(-) and I(-)/I(3)(-). The effects of additive Li(+) ions and the HOMO levels of the dyes have an important influence on properties of the dyes and performance of DSCs. The addition of Li(+) ions in electrolytes can broaden the absorption spectra of the dyes on TiO(2) films and shift both the LUMO levels of the dyes and the conduction band of TiO(2), thus leading to the increase of J(sc) and the decrease of V(oc). Upon using Br(-)/Br(3)(-) instead of I(-)/I(3)(-), a large increase of V(oc) is attributed to the enlarged energy difference between the redox potentials of electrolyte and the Fermi level of TiO(2), as well as the suppressed electron recombination. Incident photon to current efficiency (IPCE) action spectra, electrochemical impedance spectra, and nanosecond laser transient absorption reveal that both the electron collection yields and the dye regeneration yields (Φ(r)) depend on the potential difference (the driving forces) between the oxidized dyes and the Br(-)/Br(3)(-) redox couple. For the dyes for which the HOMO levels are more positive than the redox potential of Br(-)/Br(3)(-) sufficient driving forces lead to the longer effective electron-diffusion lengths and almost the same efficient dye regenerations, whereas for the dyes for which the HOMO levels are similar to the redox potential of Br(-)/Br(3)(-), insufficient driving forces lead to shorter effective electron-diffusion lengths and inefficient dye regenerations.

A Double-Band Tandem Organic Dye-sensitized Solar Cell with an Efficiency of 11.5%

The absorption spectra of most org. dyes reported thus far used for mesoporous nanostructured dye-sensitized solar cells mainly cover the visible-light region. This has motivated research towards t ...

Molecular Design to Improve the Performance of Donor–π Acceptor Near‐IR Organic Dye‐Sensitized Solar Cells

A novel near-IR charge-transfer complex, as a D-π-A-type mol., has a lateral anchoring group and a flexible long carbon chain that replaces the Me group of the donor part of the mol. This carbon chain seems to prevent the formation of mol. aggregates on the semiconductor (TiO2) nanoparticles, thus blocking charge recombination at relatively high open-circuit voltages and short-circuit photocurrent densities. This sensitizer dye has a max. IPCE (incident-photon-to-current conversion efficiencies) of 93% at 660 nm and an overall solar-energy-to-electricity conversion efficiency of 5.1%.

Dye-sensitized nanostructured ZnO Electrodes for solar cell applications

This chapter describes dye-sensitized nanostructured ZnO electrodes for solar cell applications. Dye-sensitized nanostructured solar cells (DNSCs) based on nanostructured metal oxide films have att ...

Development of hybrid organic-inorganic materials for efficient charging/discharging in electrochemical and photoelectrochemical capacitors

A composite system of poly (3,4-ethylenedioxythiophene)/multi-walled carbon nanotubes has been investigated and characterized as a potential charge storage material for coupled dye-sensitized solar cell/electrochem. capacitor systems. The selected material can easily operate in org. media (lithium triflate/propylene carbonate) giving a specific capacitance of 95 F g-1 and energy d. of 3.1 Wh kg-1. The combination of the composite material with dye-sensitized solar cell allows to obtain a photo-rechargeable supercapacitor (photocapacitor), destined to work with dies required org. media (here with N 719 dye). The photocapacitor system was built from mesoporous TiO2 electrode, typical charge relay consisting of iodine/iodide redox couple and two charge storage electrodes sepd. by a liq. electrolyte. The system was tested under light illumination of 100 mW cm-2 with xenon lamp equipped with cut-off filters eliminating the UV and IR part of the spectra.

Electric characteristics of MgO-doped TiO2 nanocrystalline film in dye-sensitized solar cells

TiO2 were doped with MgO by thermal hydrolysis, The photoelectrochemical properties of the 1%MgO-doped TiO2 film matched with organic dye TH305 were better than those of the anatase TiO2 film. The conduction band of the MgO doped nanostructured TiO2 synthesized negatively shifted by 60 mV, compared to that of undoped TiO2.