The development of high voltage solar cells is an attractive way to use sunlight for solar‐to‐fuel devices, multijunction solar‐to‐electric systems, and to power limited‐area consumer electronics. By designing a low‐oxidation‐potential organic dye (
A series of iron polypyridyl redox shuttles were synthesized in the 2+ and 3+ oxidation states and paired with a series of wide optical gap organic dyes with weak aryl ether electron‐donating groups. High voltage dye‐sensitized solar cell (HV‐DSC) devices were obtained through controlling the redox shuttle energetics and dye donor structure. The use of aryl ether donor groups, in place of commonly used aryl amines, allowed for the lowering of the dye ground‐state oxidation potential which enabled challenging to oxidize redox shuttles based on Fe2+polypyridyl structures to be used in functional devices. By carefully designing a dye series that varies the number of alkyl chains for TiO2surface protection, the recombination of electrons in TiO2to the oxidized redox shuttle could be controlled, leading to HV‐DSC devices of up to 1.4 V.
more » « less- Award ID(s):
- 1757220
- NSF-PAR ID:
- 10286463
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemSusChem
- Volume:
- 14
- Issue:
- 15
- ISSN:
- 1864-5631
- Page Range / eLocation ID:
- p. 3084-3096
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract RR9 )/redox shuttle (Fe(bpy)33+/2+) pair for dye‐sensitized solar‐cell (DSSC) devices, the highest single device photovoltage (1.42 V) has been realized for a DSSC not relying on doped TiO2. Additionally, Fe(bpy)33+/2+offers a robust, readily tunable ligand platform for redox potential tuning.RR9 can be regenerated with a low driving force (190 mV), and by utilizing theRR9 /Fe(bpy)33+/2+redox shuttle pair in a subcell for a sequential series multijunction (SSM)‐DSSC system, one of the highest known three subcell photovoltage was attained for any solar‐cell technology (3.34 V, >1.0 V per subcell). -
Three copper redox shuttles ([Cu( 1 )] 2+/1+ , [Cu( 2 )] 2+/1+ , and [Cu( 3 )] 2+/1+ ) featuring tetradentate ligands were synthesized and evaluated computationally, electrochemically, and in dye-sensitized solar cell (DSC) devices using a benchmark organic dye, Y123 . Neutral polyaromatic ligands with limited flexibility were targeted as a strategy to improve solar-to-electrical energy conversion by reducing voltage losses associated with redox shuttle electron transfer events. Inner-sphere electron transfer reorganization energies ( λ ) were computed quantum chemically and compared to the commonly used [Co(bpy) 3 ] 3+/2+ redox shuttle which has a reported λ value of 0.61 eV. The geometrically constrained biphenyl-based Cu redox shuttles investigated here have lower reorganization energies (0.34–0.53 eV) and thus can potentially operate with lower driving forces for dye regeneration (Δ G reg ) in DSC devices when compared to [Co(bpy) 3 ] 3+/2+ -based devices. The rigid tetradentate ligand design promotes more efficient electron transfer reactions leading to an improved J SC (14.1 mA cm −2 ), higher stability due to the chelate effect, and a decrease in V lossOC for one of the copper redox shuttle-based devices.more » « less
-
more » « less
Abstract Sequential series multijunction dye‐sensitized solar cells (SSM‐DSCs) can power solar‐to‐fuel processes with a single illuminated area device. Dye selection and strategies limiting photon losses are critical in SSM‐DSC devices for higher performance systems. Herein, an efficient and readily applicable spin coating protocol on glass surfaces with an antireflective fluoropolymer (CYTOP) is applied to an SSM‐DSC architecture. Combining CYTOP with the use of an immersion oil between glass spacers in a three subcell SSM‐DSC with judiciously selected TiO2photoanode sensitizers and thicknesses, an overall power conversion efficiency (PCE) of 10.1% is obtained with an output of 2.3 V. Without external bias, this SSM‐DSC configuration shows an impressive overall solar‐to‐fuel conversion efficiency of 6% when powering IrO2and Au2O3electrocatalysts for CO2and H2O to CO and H2conversion in aqueous solution. The role of CYTOP, immersion oil, sensitizer selection, and film thickness on SSM‐DSC devices is discussed along with the stability of this system.
-
more » « less
Chemical redox reactions between redox shuttles and lithium-ion battery particles have applications in electrochemical systems including redox-mediated flow batteries, photo-assisted lithium-ion batteries, and lithium-ion battery overcharge protection. These previous studies, combined with interest in chemical redox of battery materials in general, has resulted in previous reports of the chemical oxidation and/or reduction of solid lithium-ion materials. However, in many of these reports, a single redox shuttle is the focus and/or the experimental conditions are relatively limited. Herein, a study of chemical redox for a series of redox shuttles reacted with a lithium-ion battery cathode material will be reported. Both oxidation and reduction of the solid material with redox shuttles as a function of time will be probed using ferrocene derivatives with different half-wave potentials. The progression of the chemical redox was tracked by using electrochemical analysis of the redox shuttles in a custom electrochemical cell, and rate constants for chemical redox were extracted from using two different models. This study provides evidence that redox shuttle-particle interactions play a role in the overall reaction rate, and more broadly support that this experimental method dependent on electrochemical analysis can be applied for comparison of redox shuttles reacting with solid electroactive materials.
-
The high bond dissociation energy of C–C σ-bonds presents a challenge to chemical conversions in organic synthesis, polymer degradation, and biomass conversion that require chemoselective C–C bond cleavage at room temperature. Dye-sensitized photoelectrochemical cells (DSPECs) incorporating molecular organic dyes could offer a means of using renewable solar energy to drive these types of energetically demanding chemoselective C–C bond cleavage reactions. This study reports the solar light-driven activation of a bicyclic aminoxyl mediator to achieve C–C bond cleavage in the aryl-ether linkage of a lignin model compound (LMC) at room temperature using a donor–π-conjugated bridge–acceptor (D–π–A) organic dye-based DSPEC system. Mesoporous TiO 2 photoanode surfaces modified with 5-[4-(diphenylamino)phenyl]thiophene-2-cyanoacrylic acid (DPTC) D–π–A organic dye were investigated along with a bicyclic aminoxyl radical mediator (9-azabicyclo[3,3,1]nonan-3-one-9-oxyl, KABNO) in solution with and without the presence of LMC. Photophysical studies of DPTC with KABNO showed intermolecular energy/electron transfer under 1 sun illumination (100 mW cm −2 ). Under illumination, the D–π–A type DPTC sensitized TiO 2 photoanodes facilitate the generation of the reactive oxoammonium species KABNO+ as a strong oxidizing agent, which is required to drive the oxidative C–C bond cleavage of LMC. The photoelectrochemical oxidative reaction in a complete DSPEC with KABNO afforded C–C bond cleavage products 2-(2-methoxyphenoxy)acrylaldehyde (94%) and 2,6-dimethoxy-1,4-benzoquinone (66%). This process provides a first report utilizing a D–π–A type organic dye in combination with a bicyclic nitroxyl radical mediator for heterogeneous photoelectrolytic oxidative cleavage of C–C σ-bonds, modeled on those found in lignin, at room temperature.more » « less
