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Jessica Krueger

Bio: Jessica Krueger is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Dye-sensitized solar cell & Charge carrier. The author has an hindex of 3, co-authored 5 publications receiving 1057 citations.

Papers
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Journal ArticleDOI
TL;DR: A high surface area pn-heterojunction between TiO2 and an organic p-type charge transport material (spiro-OMeTAD) was sensitized to visible light using lead sulfide (PbS) quantum dots as mentioned in this paper.
Abstract: A high surface area pn-heterojunction between TiO2 and an organic p-type charge transport material (spiro-OMeTAD) was sensitized to visible light using lead sulfide (PbS) quantum dots. PbS quantum dots were formed in situ on a nanocrystalline TiO2 electrode using chemical bath deposition techniques.1 The organic hole conductor was applied from solution to form the sensitized heterojunction. The structure of the quantum dots was analyzed using HRTEM technique. Ultrafast laser photolysis experiments suggested the initial charge separation to proceed in the subpicosecond time range. Transient absorption laser spectroscopy revealed that interfacial charge recombination of the initially formed charge carriers is much faster than in comparable dye-sensitized systems.2,3 The sensitized heterojunction showed incident photon-to-electron conversion efficiencies (IPCE) of up to 45% and energy conversion efficiencies under simulated sunlight AM1.5 (10 mW/cm2) of 0.49%.

749 citations

Journal ArticleDOI
TL;DR: In this article, the onset wavelengths of the surface photovoltage (SPV) in dye-sensitized solar cells (DSSCs) with different mesoporous, wideband gap electron conductor anode materials, viz., TiO2 (anatase), Nb2O5 (amorphous and crystalline), and SrTiO3, using the same Ru bis-bipyridyl dye for all experiments, are different.
Abstract: The onset wavelengths of the surface photovoltage (SPV) in dye-sensitized solar cells (DSSCs) with different mesoporous, wide-band gap electron conductor anode materials, viz., TiO2 (anatase), Nb2O5 (amorphous and crystalline), and SrTiO3, using the same Ru bis-bipyridyl dye for all experiments, are different. We find a clear dependence of these onset wavelengths on the conduction band edge energies (ECB) of these oxides. This is manifested in a blue-shift for cells with Nb2O5 and SrTiO3 compared to those with TiO2. The ECB levels of Nb2O5 and SrTiO3 are known to be some 200−250 meV closer to the vacuum level than that of our anatase films, while there is no significant difference between the optical absorption spectra of the dye on the various films. We, therefore, suggest that the blue shift is due to electron injection from excited-state dye levels above the LUMO into Nb2O5 and SrTiO3. Such injection comes about because, in contrast to what is the case for anatase, the LUMO of the adsorbed dye in the s...

329 citations

Proceedings ArticleDOI
24 Feb 2003
TL;DR: The photovoltaic performance of solid-state dye-sensitized solar cells based on spiro-MeOTAD (2,2'7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene) has been improved to 3.2% overall conversion efficiency under air mass AM 1.5 illumination by performing the dye adsorption in the presence of silver ions in the dye solution.
Abstract: The photovoltaic performance of solid-state dye-sensitized solar cells based on spiro-MeOTAD (2,2'7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9'-spirobifluorene) has been improved to 3.2% overall conversion efficiency under air mass AM 1.5 illumination by performing the dye adsorption in the presence of silver ions in the dye solution. Different spectroscopic methods, such as X-ray photoelectron, Fourier-transform infrared and UV-visible spectroscopy have been employed to scrutinize the impact of the silver on the dye-sensitized device. From spectroscopic evidence it is inferred that the silver binds to the sensitizer mainly via the amphidentate thiocyanate, allowing the formation of ligand-bridged dye complexes. The enhancement in overall device efficiency is a result of increased open circuit potential and short circuit current. The increased open circuit voltage was explained by the blocking of the dark current as a result of a closer packed dye layer and/or the partial formation of a dye double layer upon silver coordination. The increased short circuit current corresponds to the higher amount of ruthenium dye units adsorbed to the TiO 2 surface.

4 citations

Proceedings ArticleDOI
05 Feb 2001
TL;DR: A dye-sensitized mesoporous films of TiO2 are low cost alternatives to inorganic semiconductor devices as mentioned in this paper, and solar energy conversion efficiencies of up to 10% have been achieved with such films when used in conjunction with liquid electrolytes.
Abstract: Solar cells based on dye-sensitized mesoporous films of TiO2 are low cost alternatives to inorganic semiconductor devices. Solar energy conversion efficiencies of up to 10% have been achieved with such films when used in conjunction with liquid electrolytes. Practical advantage may be gained by the replacement of the liquid electrolyte with a solid charge transport material and various concepts have been proposed in literature to realize such solid-state dye-sensitized heterojunctions. Recently high incident photon to electric current conversion efficiencies have been achieved with a cell consisting of a dye-derivatized mesoporous TiO2 film contacted by a new organic hole conductor. Photoinduced charge carrier generation shows to be very efficient in such devices, while interfacial charge recombination during charge collection can be revealed as the major loss mechanism. Surface treatments with pyridine derivatives proved to significantly improve the energy conversion efficiency of the device.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

4 citations

Proceedings ArticleDOI
06 Feb 2004
TL;DR: Reference LPI-CONF-2004-021View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12 as mentioned in this paper, created on 2016
Abstract: Reference LPI-CONF-2004-021View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

1 citations


Cited by
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Journal ArticleDOI
TL;DR: Two organolead halide perovskite nanocrystals were found to efficiently sensitize TiO(2) for visible-light conversion in photoelectrochemical cells, which exhibit strong band-gap absorptions as semiconductors.
Abstract: Two organolead halide perovskite nanocrystals, CH3NH3PbBr3 and CH3NH3PbI3, were found to efficiently sensitize TiO2 for visible-light conversion in photoelectrochemical cells. When self-assembled on mesoporous TiO2 films, the nanocrystalline perovskites exhibit strong band-gap absorptions as semiconductors. The CH3NH3PbI3-based photocell with spectral sensitivity of up to 800 nm yielded a solar energy conversion efficiency of 3.8%. The CH3NH3PbBr3-based cell showed a high photovoltage of 0.96 V with an external quantum conversion efficiency of 65%.

16,634 citations

Journal ArticleDOI
TL;DR: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency as mentioned in this paper, and many DSC research groups have been established around the world.
Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

8,707 citations

Journal ArticleDOI
TL;DR: The use of a solid hole conductor dramatically improved the device stability compared to (CH3NH3)PbI3 -sensitized liquid junction cells.
Abstract: We report on solid-state mesoscopic heterojunction solar cells employing nanoparticles (NPs) of methyl ammonium lead iodide (CH3NH3)PbI3 as light harvesters. The perovskite NPs were produced by reaction of methylammonium iodide with PbI2 and deposited onto a submicron-thick mesoscopic TiO2 film, whose pores were infiltrated with the hole-conductor spiro-MeOTAD. Illumination with standard AM-1.5 sunlight generated large photocurrents (JSC) exceeding 17 mA/cm2, an open circuit photovoltage (VOC) of 0.888 V and a fill factor (FF) of 0.62 yielding a power conversion efficiency (PCE) of 9.7%, the highest reported to date for such cells. Femto second laser studies combined with photo-induced absorption measurements showed charge separation to proceed via hole injection from the excited (CH3NH3)PbI3 NPs into the spiro-MeOTAD followed by electron transfer to the mesoscopic TiO2 film. The use of a solid hole conductor dramatically improved the device stability compared to (CH3NH3)PbI3 -sensitized liquid junction cells.

6,751 citations

Book
03 Aug 2010
TL;DR: The dye-sensitized solar cells (DSC) as discussed by the authors provides a technically and economically credible alternative concept to present day p-n junction photovoltaic devices, where light is absorbed by a sensitizer, which is anchored to the surface of a wide band semiconductor.
Abstract: The dye-sensitized solar cells (DSC) provides a technically and economically credible alternative concept to present day p–n junction photovoltaic devices. In contrast to the conventional systems where the semiconductor assume both the task of light absorption and charge carrier transport the two functions are separated here. Light is absorbed by a sensitizer, which is anchored to the surface of a wide band semiconductor. Charge separation takes place at the interface via photo-induced electron injection from the dye into the conduction band of the solid. Carriers are transported in the conduction band of the semiconductor to the charge collector. The use of sensitizers having a broad absorption band in conjunction with oxide films of nanocrstalline morphology permits to harvest a large fraction of sunlight. Nearly quantitative conversion of incident photon into electric current is achieved over a large spectral range extending from the UV to the near IR region. Overall solar (standard AM 1.5) to current conversion efficiencies (IPCE) over 10% have been reached. There are good prospects to produce these cells at lower cost than conventional devices. Here we present the current state of the field, discuss new concepts of the dye-sensitized nanocrystalline solar cell (DSC) including heterojunction variants and analyze the perspectives for the future development of the technology.

4,159 citations

Journal ArticleDOI
TL;DR: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each that are among the hottest research topics of the last decades.
Abstract: Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each. Their size ranges from 2-3 to about 20 nm. What is special about this size regime that placed NCs among the hottest research topics of the last decades? The quantum mechanical coupling * To whom correspondence should be addressed. E-mail: dvtalapin@uchicago.edu. † The University of Chicago. ‡ Argonne National Lab. Chem. Rev. 2010, 110, 389–458 389

3,720 citations