Functionalized pentacenes for dye-sensitized solar cells

Li, Zhong; Shankar, Karthik; Mor, Gopal K.; Grimminger, Robert A.; Lin, Chih-Min; Anthony, John E.; Grimes, Craig A.

doi:10.1117/1.3553781

Cited by 12 publications

(13 citation statements)

References 42 publications

(40 reference statements)

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Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4] DSSCs consist of four main parts, that is, a wide band gap metal-oxide semiconductor deposited on top of a fl uorine-doped tin oxide (FTO) electrode, a dye anchored to the surface of the semiconductor electrode, a liquid or solid electrolyte, and a platinized counter-electrode. [2][3][4] As the cornerstone of DSSCs, the optimization of the semiconductor electrode that consists of n-type materials like titanium dioxide (TiO 2 ) or zinc oxide (ZnO), on one hand, or of p-type materials like nickel oxide (NiO) or copper oxide (CuO), on the other hand, is still one of the major research targets. [2][3][4] As the cornerstone of DSSCs, the optimization of the semiconductor electrode that consists of n-type materials like titanium dioxide (TiO 2 ) or zinc oxide (ZnO), on one hand, or of p-type materials like nickel oxide (NiO) or copper oxide (CuO), on the other hand, is still one of the major research targets.…”

Section: Introductionmentioning

confidence: 99%

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Binary Indium–Zinc Oxide Photoanodes for Efficient Dye‐Sensitized Solar Cells

Kunzmann

Stanzel

Costa

et al. 2015

Advanced Energy Materials

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typically made from TiO 2 , [ 3,6 ] ZnO photoanodes have emerged, in recent years, as a viable alternative. [ 7,8 ] First, ZnO fi lms feature higher electron mobilities (155 cm 2 V −1 s −1 at 300 K) and a wider band gap (3.4 eV) relative to TiO 2 fi lms. [ 7 ] Second, the ease of preparation of ZnO nanostructures compared to TiO 2 is a further asset. [ 7 ] Third, the electron injection and recombination dynamics under comparable operation conditions are similar for both types of electrodes.The most signifi cant drawbacks of ZnObased DSSCs are, however, their low stability under working conditions in acidic environments and their prominent electron loss processes. For example, injected conduction band (CB) electrons tend to recombine with either the oxidized dye or the electrolyte in close proximity to the electrode surface. In addition, low injection yields lead to relaxation processes, in which the excited dye relaxes to the ground state. The earlier and the latter, which impact the electron lifetime and the effective electron diffusion length throughout the electrode, result in poor charge collection effi ciencies. [ 9 ] Hence, research toward more effi cient and stable ZnO-based electrodes is at the forefront of investigations. [ 6 ] To tackle these aspects, different groups have demonstrated the potential of n-or p-type doping of ZnO electrodes in the context of reducing charge recombination rates-arsenic, aluminum, carbon nanotubes, gallium, graphene, lithium, potassium, tin, etc., as well as nitrogen and phosphorous are the most commonly employed doping reagents. [ 8,[10][11][12] To this end, most of the efforts have focused on zinc stannate (SZO), [ 13,14 ] reaching maximum effi ciencies of as high as 6%. [ 14 ] SZO-based devices feature high stability, good fi ll factors (FF), and high open circuit voltages ( V oc ). [ 14 ] The limiting factor is, however, the moderate short-circuit current density ( J sc ) of around 15 mA cm −2 . To achieve high effi ciencies in binary metal oxide electrodes in DSSCs, the latter calls for improvement by means of optimizing the overall charge collection effi ciency. To this end, the current work documents the optimization of indium-zinc oxide (IZO) as photoanode materials that could compete with the state-of-the-art SZO devices. Our choice of IZO is based on the fact that their fi lms feature higher electron conducting properties than SZO, [ 15 ] from which longer electron lifetimes and higher charge collection effi ciencies are expected to amplify J sc .The benefi ts of incorporating binary metal-oxide electrodes en route toward effi cient dye-sensitized solar cells (DSSCs) have recently emerged. The current work aims at realizing effi cient indium-doped zinc oxide based DSSCs by means of enhancing charge transport processes and reducing recombination rates. Electrochemical impedance spectroscopic assays corroborate that low amounts of indium reduce charge transport resistances and increase electron recombination resistances. The latter are in concert with a remark...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Binary Indium–Zinc Oxide Photoanodes for Efficient Dye‐Sensitized Solar Cells

Kunzmann

Stanzel

Costa

et al. 2015

Advanced Energy Materials

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“…The J-V characteristics of the fabricated TiO 2 nanotube array-polymer solar cells under AM 1.5 global illumination are shown in Figure 4(a). The short circuit density is 12.43 mA/cm 2 , the open circuit potential was 641 mV, and the fill factor was 0.511, resulting in an overall conversion efficiency of 4.07%. We surmise that the coiling of the polymer chains inside the nanotube pores, as manifested by the blue shift in the absorption peak relative to the neat unannealed film, may be responsible for relatively poor hole transport thus negatively impacting the fill factor.…”

Section: Use Of 1d Nanomaterials In Bulk Heterojunction Ordered Hetementioning

confidence: 99%

“…Third-generation photovoltaics encompass a variety of designs including liquid-based dye-sensitized (Gråtzel) solar cells, solid-state bulk heterojunction solar cells [1][2][3][4][5][6], ordered heterojunction solar cells [7,8], Förster resonance energy transfer-(FRET-) based solar cells [9][10][11][12][13][14], and organic solar cells [15,16]. Liquid-based dye-sensitized solar cells (DSSCs) utilizing for a photoanode a dye-coated layer of TiO 2 nanoparticles have reached efficiencies of over 11% [17], but there are concerns with respect to manufacturing photovoltaic panels with a liquid redox electrolyte.…”

Section: Introductionmentioning

confidence: 99%

“…(a) shows that a 1 μm long TiO 2 nanotube array yields a short circuit photocurrent density of 10.1 mA/cm2 , an open circuit potential of 743 mV, and a fill factor of 0.55 resulting in an overall conversion efficiency of 4.1%.Figure 23(b) presents the performance of a similar solar cell constructed by sensitizing a TiCl 4 -treated 1 μm long transparent nanotube array with N-719. While the use of N-719 results in slightly larger values of the open circuit potential, the short circuit photocurrent density J sc is nearly half that obtained with Ru-TPA-NCS sensitization because of the smaller amount of light harvested.…”

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confidence: 99%

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Self-Organized One-DimensionalTiO2Nanotube/Nanowire Array Films for Use in Excitonic Solar Cells: A Review

Bao

Feng²,

Grimes

2012

Journal of Nanotechnology

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Synthesis of Unsymmetrical Derivatives of Pentacene for Materials Applications

Tykwinski

2019

Acc. Chem. Res.

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Conspectus Pentacene shows unique electronic properties that have long been appreciated and exploited. Over the past 20 years, new synthetic schemes have been developed to address some of the problems encountered with pristine pentacene (e.g., stability and solubility), and pentacene derivatives have become a mainstay in the realm of organic semiconductors in applications such as organic light-emitting diodes, organic field-effect transistors (OFETs), and organic photovoltaics. At the onset of our work, the vast majority of known pentacene derivatives featured a symmetrical structure, often as the result of synthetic protocols that rely on nucleophilic additions to 6,13-pentacenequinone (PQ). The assembly of pentacenes featuring an unsymmetrical framework held great appeal, but the stepwise formation of derivatives, in which a specific function might be incorporated through each individual addition step, did not exist. This Account presents contributions from our lab and others to the synthesis and study of unsymmetrical pentacene derivatives. PQ offers an ideal platform for desymmetrization through the sequential addition of nucleophiles to each of the two ketone groups. Addition can be completed in a one-pot protocol, or through individual steps in which the product of the first addition is isolated and used as a precursor in the divergent synthesis of a series of structurally related molecules. This general approach has been used to assemble pentacene derivatives appended with alkynyl/aryl/alkyl groups, polarized frameworks via substitution with donor and/or acceptor groups, and conjugated oligomers linked by butadiynyl moieties. Stepwise substitution also provides derivatives with remarkable functionality, including pentacene–porphyrin dyads, pendent TEMPO free radicals, cyanoacrylic acid anchor groups (for incorporation into dye-sensitized solar cells), and derivatives with ambipolar behavior for OFET devices. The study of intramolecular singlet fission (iSF) has emerged as one of the most fruitful applications of unsymmetrical pentacene derivatives. SF involves the spontaneous splitting of a photoexcited singlet state (S1) in one chromophore into a pair of triplets (T1) shared with a neighboring chromophore. Pentacene derivatives are particularly well suited for this since E(S1) ≥ 2E(T1) satisfies the thermodynamic requirements for SF, and they have the additional feature that two chromophores can be tethered together by a “spacer” that allows spectroscopic studies of iSF to be done in dilute solution. From a synthetic perspective, the major advantage of the dimeric structure is the ability to modify the spacer, which allows for control over the distance, geometric relationship, and electronic coupling between the two pentacene groups. Dimeric pentacenes are central to providing an in-depth understanding of the molecular mechanism of SF, often providing advances not possible from measurements in the solid state.

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Functionalized pentacenes for dye-sensitized solar cells

Cited by 12 publications

References 42 publications

Binary Indium–Zinc Oxide Photoanodes for Efficient Dye‐Sensitized Solar Cells

Binary Indium–Zinc Oxide Photoanodes for Efficient Dye‐Sensitized Solar Cells

Self-Organized One-DimensionalTiO2Nanotube/Nanowire Array Films for Use in Excitonic Solar Cells: A Review

Synthesis of Unsymmetrical Derivatives of Pentacene for Materials Applications

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