Full Visible Spectrum Panchromatic Triple Donor Dye for Dye-Sensitized Solar Cells

Abstract

An organic dye with three electron donating groups is studied that has broad full visible spectrum panchromatic absorption in solution. The donor groups introduce six significant optical transitions spaced throughout the visible spectrum to give a dye with near uniform molar absorptivity across the visible spectrum. This unique material is characterized by optical, electrochemical, and computational methods. Within dye-sensitized solar cell (DSC) devices, this material shows a strong photocurrent output of ∼20 mA/cm2 with no cosensitization. DSC devices are characterized through impedance spectroscopy, current–voltage curve analysis, and incident photon-to-current conversion efficiency measurements. Importantly, minimal DSC device performance loss is observed after 500 h of continuous irradiation.

Indoline-Based Donor-π-Acceptor Visible-Light Responsive Organic Dyes for Dye-Sensitized Solar Cells: Co-sensitization with Squaraine Dye for Panchromatic IPCE Response

“…Metal-free organic dyes with D-A-D architectures gave 6.0–7.92% DSSC device efficiencies without chenodeoxycholic acid (CDCA); − further incorporation of π-spacers and acceptor units into D-A-D dyes gave maximum efficiencies of 6.72 and 8.9% without and with CDCA, respectively. Besides co-sensitizations and NIR-light absorption, the panchromatic light absorption from visible to NIR regions is essential to gain high DSSC device efficiency. ,− Furthermore, the aggregation of dyes on the TiO 2 surface and interfacial charge recombination limit the DSSC device efficiency and can be controlled by wrapping the dye with alkyl or bulky aryl groups that ultimately boost device V OC , J SC , and efficiencies . The interfacial dipole moment of dyes on the TiO 2 surface plays an important role in DSSC device efficiency by affecting the device V OC directly.…”

Effects of Proaromaticity on Excited-State Lifetimes and Charge Separation in Near-Infrared Sensitizer Dyes in Solution and on TiO2

“…The additional donor groups result in added higher energy transitions for a panchromatic absorption profile and could delocalize the cation after electron injection. 30 Two NL6 derivatives are also synthesized and investigated where the cyanoacrylic acid moiety is replaced with either a dicyano (JW2) or diester C213, 27 PB1, 41 NL6, 28 and JW1 30 were prepared as previously described. JW2 and JW3 were prepared via Knoevenagel condensation as described below from aldehyde (1), which is a common intermediate in the NL6 synthesis (Scheme 1).…”

“…We previously introduced a sensitizing dye ( PB1 ) using 3,4-thienothiophene (3,4-TT) − as a proaromatic-conjugated π-bridge. Devices incorporating PB1 demonstrated PCEs of up to 7.8% and longer wavelength absorption onset in solution at ∼665 nm (compared to 5.9% PCE and a ∼590 nm onset for the non-proaromatic analogues C1 and C213 ). , Proaromaticity has also been implemented in DSC dye studies utilizing thienopyrazine (TPz)- − and indolizine- ,, based building blocks both experimentally and computationally. In general, dyes incorporating 3,4-TT- ,, and TPz- − based building blocks have shown exceptional promise in a variety of DSC devices.…”

Amphiphilic Indoline-Based Unsymmetrical Squaraine Dyes for Dye-Sensitized Solar Cells: Modulating the Dye-TiO2/Electrolyte Interface for Nonaqueous and Aqueous Electrolytes

“…Mesoporous thin films of semiconducting TiO 2 have made dye-sensitized solar cells (DSSCs) very attractive since 1991 over single-crystal TiO 2 -based photoanodes. , DSSCs are potential alternatives to inorganic solar cells due to their low fabrication cost and because they are easy to make. ,− Great efforts have been made by researchers on developing dyes with new architecture besides electrolytes, anodic metal oxides, and counter electrodes to gain high DSSC efficiency. − To date, many high efficient DSSC devices made of ruthenium-complexes and zinc porphyrin dyes with the efficiencies of 10–13%. − Upon several modulations of electronic and steric properties of the metal-free organic dyes, 10–13.6% efficiencies have been achieved with different architectures. − NIR-light absorbing characters of dyes are necessary to achieve high DSSC photocurrents and efficiencies besides the panchromatic light absorption and cosensitization. ,,− In this context, squaraine dyes are very promising and potential dyes for DSSC applications because they harvest light from the visible to the NIR region with a high extinction coefficient . Furthermore, tunable optical properties by structural modulation make squaraine dyes more specific over the other metal-free organic dye architecture .…”