Surface Photovoltage Spectroscopy Resolves Interfacial Charge Separation Efficiencies in ZnO Dye-Sensitized Solar Cells

Rodríguez-Pérez, Manuel; Canto-Aguilar, Esdras J.; García-Rodríguez, Rodrigo; Denko, Alexandra T. De; Oskam, Gerko; Osterloh, Frank E.

doi:10.1021/acs.jpcc.7b11727

Cited by 28 publications

(16 citation statements)

References 57 publications

(87 reference statements)

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“…[42c], In particular, Co(II)/Co(III) complexes with the TCB ion have drawn attention as redox shuttle for DSSCs in recent years. [56f], [57d], [57g], The application of IL‐based electrolytes in photovoltaic devices was reviewed, recently. [55v], [57j], [60h], Further information on selected properties and applications of tetracyanoborate ionic liquids can be found in recent review articles[52a], [53g], [58b], and a monograph…”

Section: Tetracyanoborates (Kttcb)mentioning

confidence: 99%

Cyanoborates

Ignat’ev

Finze

2019

Eur J Inorg Chem

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Cyanoborate chemistry has emerged to an important topic during the last two decades, beginning with two independent reports on the successful synthesis of the tetracyanoborate anion [B(CN) 4 ]in 2000. A wealth of cyanoborate anions with different substituents in addition to CN group(s) bonded to boron, i.e. hydrogen, halogen, aryl, alkenyl, alkyl, perfluoroalkyl, and alkoxy, have been developed, which enable the tuning of properties of compounds and materials based on them. The readily accessible alkali metal cyanoborates are convenient starting materials for the preparation of cyanoborates with various organic, inorganic, and metal cations as well as cyanoborate coordination compounds. A focus has been on low-[a] Julius-Maximilians-Universität Würzburg,

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Section: Tetracyanoborates (Kttcb)mentioning

confidence: 99%

Cyanoborates

Ignat’ev

Finze

2019

Eur J Inorg Chem

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“…As can be seen in Figure , the conduction band edges of both SrTiO 3 and TiO 2 lie above the conduction band edges of FTO and ITO, allowing photochemical charge transfer from the ETL to the TCO. From the band edge offset, the theoretical photovoltage can be calculated, as shown previously. , This yields −0.7 V (TiO 2 /FTO) and −0.46 V (TiO 2 /ITO), slightly larger than the experimental values of −0.3 to −0.4 V for TiO 2 /FTO and −0.25 to −0.3 V for TiO 2 /ITO in Figures , S2, and S3. For SrTiO 3 , the theoretical photovoltage values (−1.5 V for SrTiO 3 /FTO and −1.26 V for SrTiO 3 /ITO) are somewhat smaller than the experimental values (−1.5 to −2.2 V for SrTiO 3 /FTO and −1.0 to −1.7 V for SrTiO 3 /ITO).…”

Section: Resultsmentioning

confidence: 60%

“…The former is a measure of the experimental electron transfer, while the latter is a measure of the thermodynamic driving force for electron transfer. Thus, the ratio between these two parameters allows a comparison of the electron transfer efficiency of the dyes, independent of the driving force …”

Section: Resultsmentioning

confidence: 99%

“…While KFM uses fixed illumination, in SPS, the wavelength of the illumination is varied. The measured surface photovoltage (ΔCPD under illumination) then provides information about the effective band gap of the absorber, defect states, the majority carrier type, and the efficiency of charge transfer. − For DSSCs derived from the organic fluorenyl-thiophene dye (OD-8), we recently used SPS to confirm the importance of the dye regeneration reaction for achieving good charge separation at dye. Additionally, the formation of Zn 2+ –dye aggregates was observed in ZnO-sensitized films .…”

Section: Introductionmentioning

confidence: 99%

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Photochemical Charge Separation and Dye Self-Oxidation Control Performance of Fluorescein, Rose Bengal, and Triphenylamine Dye-Sensitized Solar Cells

et al. 2020

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The charge transfer kinetics between the dye, metal oxide film, and the transparent conductive oxide substrate are key to the optimization of dye-sensitized solar cells (DSSC). Here, we use surface photovoltage spectroscopy (SPS) to analyze photochemical charge separation and transfer in DSSCs made from D35, fluorescein, or Rose Bengal organic dyes, using either titanium dioxide or strontium titanate as electron transfer layers (ETL) and fluorine-doped tin oxide (FTO) or indium-doped tin oxide (ITO) as transparent conductive substrates. DSSC efficiencies range from 4.612% for D35/TiO2/FTO to 0.0003% for fluorescein/SrTiO3/ITO and are generally higher for the TiO2- and FTO-based devices. According to SPS, electron transfer from the dye into the SrTiO3 ETL is less reversible and accompanied by self-oxidation of the dyes. Electron transfer to FTO is more efficient than to ITO, which is attributed to the improved conductivity of the FTO/ETL configuration resulting from a higher annealing temperature and also to the higher work function of FTO. For FTO/TiO2-based devices, power conversion efficiencies correlate well with the surface photovoltage data. Overall, these results show that both efficiency and reversibility of electron transfer at the conductive substrate–ETL–dye interface are essential for DSSC performance. Additionally, we demonstrate that SPS can identify efficient dye/ETL combinations for application in improved DSSC and detect unstable dyes.

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“…Surface photovoltage (SPV) spectroscopy is a powerful technique for understanding the influence of surface electronic states on the photoresponse of materials , and has been used extensively to understand charge dynamics in a variety of semiconductor materials. − This technique involves illuminating a semiconductor material and measuring the resulting surface photovoltage, typically using a metal–insulator–semiconductor configuration. A limitation of this technique, however, is its inability to measure spatial variation, which makes it impractical for studying individual nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Surface Photovoltage Mapping of 2D Materials and Heterostructures by Illuminated Kelvin Probe Force Microscopy

Shearer

et al. 2018

J. Phys. Chem. C

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Nanomaterials are interesting for a variety of applications, such as optoelectronics and photovoltaics. However, they often have spatial heterogeneity, i.e. composition change or physical change in the topography or structure, which can lead to varying properties that would influence their applications. New techniques must be developed to understand and correlate spatial heterogeneity with changes in electronic properties. Here we highlight the technique of surface photovoltage-Kelvin probe force microscopy (SPV-KFM), which is a modified version of noncontact atomic force microscopy capable of imaging not only the topography and surface potential, but also the surface photovoltage on the nanoscale. We demonstrate its utility in probing monolayer WSe 2-MoS 2 lateral heterostructures, which form an ultrathin p-n junction promising for photovoltaic and optoelectronic applications. We show surface photovoltage maps highlighting the different photoresponse of the two material regions as a result of the effective charge separation across this junction. Additionally, we study the variations between different

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Surface Photovoltage Spectroscopy Resolves Interfacial Charge Separation Efficiencies in ZnO Dye-Sensitized Solar Cells

Cited by 28 publications

References 57 publications

Cyanoborates

Cyanoborates

Photochemical Charge Separation and Dye Self-Oxidation Control Performance of Fluorescein, Rose Bengal, and Triphenylamine Dye-Sensitized Solar Cells

Nanoscale Surface Photovoltage Mapping of 2D Materials and Heterostructures by Illuminated Kelvin Probe Force Microscopy

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