Understanding the Role of the Sulfide Redox Couple (S2–/Sn2–) in Quantum Dot-Sensitized Solar Cells

Chakrapani, Vidhya; Baker, David R.; Kamat, Prashant V.

doi:10.1021/ja203131b

Cited by 297 publications

(309 citation statements)

References 65 publications

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“…In n-type solar cells, the hole transfer from QDs to electrolyte is usually 2 to 3 orders of magnitude slower than the corresponding electron injection [45]. Thus, the hole dynamics becomes the limiting factor for the photo-conversion efficiency [46].…”

Section: Hole Trapping and Hole Injectionmentioning

confidence: 99%

Ultrafast photoinduced dynamics in quantum dot-based systems for light harvesting

et al. 2015

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KEYWORDScolloidal quantum dots, electron transfer, energy transfer, core shell quantum dots, quantum dot solar cell ABSTRACT Colloidal semiconductor nanocrystals, referred to as quantum dots, offer simple low-temperature solution-based methods for constructing optoelectronic devices such as light emitting diodes and solar cells. We review recent progress in the understanding of photoinduced processes in key components of a certain type of quantum dot solar cells where the dots sensitize a suitable metal oxide, such as ZnO or TiO 2 , for electron injection, and NiO for hole injection. The electron and hole injection dynamics are discussed in detail as a function of the quantum dot size and core-shell structure, the linker molecule type, and the morphology of the accepting metal oxide. Hole trapping is identified as a major factor limiting the performance of quantum dot-based devices. We review possible strategies for improvement that use core-shell structures and directed excitation energy transfer between quantum dots. Finally, the generation and injection of multiple excitons are revisited. We show that the assumption of a linear relationship between the intensity of transient absorption signal and the number of excitons does not generally hold, and this observation can partially explain highly disparate results for the efficiency of generating multiple excitons. A consistent calculation procedure for studies of multiple exciton generation is provided. Finally, we offer a brief personal outlook on the topic.

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Section: Hole Trapping and Hole Injectionmentioning

confidence: 99%

Ultrafast photoinduced dynamics in quantum dot-based systems for light harvesting

et al. 2015

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“…at the electrode/electrolyte interface. [28][29][30][31] Such dark current generation was also noticed with the CdS/TiO 2 photoelectrode, while the magnitude of the dark current in comparison with that of photocurrent was very small unlike the CdS/SnO 2 photoelectrode. This observation highlights that there is no direct correlation between electron transfer kinetics and photoelectrochemical performance, which is consistent with recent studies on CdSe QDs/C 60 and CdSe QDs/oxides photoelectrodes.…”

mentioning

confidence: 51%

Influence of Nanoporous Oxide Substrate on the Performance of Photoelectrode in Semiconductor-Sensitized Solar Cells

Bang¹

2012

Bulletin of the Korean Chemical Society

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Oxide substrates in semiconductor-sensitized solar cells (SSSCs) have a great impact on their performance. TiO 2 has long been utilized as an oxide substrate, and other alternatives such as ZnO and SnO 2 have also been explored due to their superior physical properties over TiO 2 . In the development of high-performance SSSCs, it is of significant importance to understand the effect of oxides on the electron injection and charge recombination as these two are major factors in dictating solar cell performance. In addition, elucidating the relationship between these two critical processes and solar cell performance in each oxide is critical in building up the basic foundation of SSSCs. In this study, ultrafast pump-probe laser spectroscopy and open-circuit decay analysis were conducted to examine the characteristics of three representative oxides (TiO 2 , ZnO, and SnO 2 ) in terms of electron injection kinetics and charge recombination, and the implication of results is discussed.

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“…Interestingly, these reactions yield nanocrystalline rutile, anatase and brookite phases of titania (all three phases of crystalline titania) at RT from the Zn 2 TiO 4 /H 2 Se, CdTiO 3 /H 2 S and CdTiO 3 / H 2 Se reactions, respectively. The meso -TiO 2 -CdSe shows photoactivity as good as any QD sensitized mesoporous titania solar cells [ 23 ] without optimization of the materials and under measurement conditions that can be further improved. The thicker automated gas adsorption analyzer (Micrometrics) in a relative pressure range, P / P 0 , from 0.01 to 0.99.…”

Section: Discussionmentioning

confidence: 99%

Molten‐Salt‐Assisted Self‐Assembly (MASA)‐Synthesis of Mesoporous Metal Titanate‐Titania, Metal Sulfide‐Titania, and Metal Selenide‐Titania Thin Films

Karakaya

Türker

Dag

2013

Adv Funct Materials

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New synthetic strategies are needed for the assembly of porous metal titanates and metal chalcogenite‐titania thin films for various energy applications. Here, a new synthetic approach is introduced in which two solvents and two surfactants are used. Both surfactants are necessary to accommodate the desired amount of salt species in the hydrophilic domains of the mesophase. The process is called a molten‐salt‐assisted self‐assembly (MASA) because the salt species are in the molten phase and act as a solvent to assemble the ingredients into a mesostructure and they react with titania to form mesoporous metal titanates during the annealing step. The mesoporous metal titanate (meso‐Zn2TiO4 and meso‐CdTiO3) thin films are reacted under H2S or H2Se gas at room temperature to yield high quality transparent mesoporous metal chalcogenides. The H2Se reaction produces rutile and brookite titania phases together with nanocrystalline metal selenides and H2S reaction of meso‐CdTiO3 yields nanocrystalline anatase and CdS in the spatially confined pore walls. Two different metal salts (zinc nitrate hexahydrate and cadmium nitrate tetrahydrate) are tested to demonstrate the generality of the new assembly process. The meso‐TiO2‐CdSe film shows photoactivity under sunlight.

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Understanding the Role of the Sulfide Redox Couple (S^2–/S_n^2–) in Quantum Dot-Sensitized Solar Cells

Cited by 297 publications

References 65 publications

Ultrafast photoinduced dynamics in quantum dot-based systems for light harvesting

Ultrafast photoinduced dynamics in quantum dot-based systems for light harvesting

Influence of Nanoporous Oxide Substrate on the Performance of Photoelectrode in Semiconductor-Sensitized Solar Cells

Molten‐Salt‐Assisted Self‐Assembly (MASA)‐Synthesis of Mesoporous Metal Titanate‐Titania, Metal Sulfide‐Titania, and Metal Selenide‐Titania Thin Films

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