Efficient photovoltaic devices for InP semiconductor/liqud junctions

Heben, Michael J.; Kumar, Amit; Zheng, Chong; Lewis, Nathan S.

doi:10.1038/340621a0

Cited by 21 publications

(18 citation statements)

References 25 publications

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“…This is consistent with the n-InP/KCl(aq)–Fe(CN) 6 3‑/4‑ junction . Compared to the data on n-InP/CH 3 OH–Me 2 Fc +/0 contacts studied previously, the low current density indicates that the hole transfer was very slow at the n-InP/Na 2 S–Na 2 SO 3 interface. This may be due to a small potential barrier formed at the n -InP/polysulfide electrolyte interface.…”

Section: Resultssupporting

confidence: 88%

“…It is widely used as photocathodes for PEC hydrogen production attributing to its favorable conduction band position for water reduction and its low surface-recombination velocity. − Recently, p-InP photocathode has achieved a benchmark solar-to-hydrogen efficiency of approximately 15.8% . The PEC properties of n-type InP has also been intensively studied but mainly using sacrificial-reagent-containing electrolytes due to its poor stability for water oxidation. − Recently, InP photoanodes with effective protective coatings have shown excellent PEC performances for water oxidation in 1.0 M KOH solution. , However, most of these studies were conducted with planar InP that has relatively small surface areas. Our group and other groups have demonstrated that 2D InP NP photoanodes exhibited superior PEC performances compared to their planar counterparts. , However, the photocurrent density is still low mainly attributed to high surface recombination at surface states .…”

Section: Introductionmentioning

confidence: 99%

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Unique Three-Dimensional InP Nanopore Arrays for Improved Photoelectrochemical Hydrogen Production

Zheng

et al. 2016

ACS Appl. Mater. Interfaces

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Ordered three-dimensional (3D) nanostructure arrays hold promise for high-performance energy harvesting and storage devices. Here, we report the fabrication of InP nanopore arrays (NPs) in unique 3D architectures with excellent light trapping characteristic and large surface areas for use as highly active photoelectrodes in photoelectrochemical (PEC) hydrogen evolution devices. The ordered 3D NPs were scalably synthesized by a facile two-step etching process of (1) anodic etching of InP in neutral 3 M NaCl electrolytes to realize nanoporous structures and (2) wet chemical etching in HCl/H3PO4 (volume ratio of 1:3) solutions for removing the remaining top irregular layer. Importantly, we demonstrated that the use of neutral electrolyte of NaCl instead of other solutions, such as HCl, in anodic etching of InP can significantly passivate the surface states of 3D NPs. As a result, the maximum photoconversion efficiency obtained with ∼15.7 μm thick 3D NPs was 0.95%, which was 7.3 and 1.4 times higher than that of planar and 2D NPs. Electrochemical impedance spectroscopy and photoluminescence analyses further clarified that the improved PEC performance was attributed to the enhanced charge transfer across 3D NPs/electrolyte interfaces, the improved charge separation at 3D NPs/electrolyte junction, and the increased PEC active surface areas with our unique 3D NP arrays.

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Unique Three-Dimensional InP Nanopore Arrays for Improved Photoelectrochemical Hydrogen Production

Zheng

et al. 2016

ACS Appl. Mater. Interfaces

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“…Figure displays the J − E data for n-InP anodes in contact with KCl(aq)−0.100 M Fe(CN) 6 4- −0.100 M Fe(CN) 6 3- . When compared to data on n-InP/CH 3 OH−Me 2 Fc +/0 contacts studied previously and reevaluated in the course of this work (Figure a), the current densities in Figure b were extremely small at low forward bias. Even at an electrode potential of −1.0 V vs E (A/A - ), the current density at the n-InP/KCl(aq)−Fe(CN) 6 3-/4- junction was only on the order of 10 -3 A cm -2 .…”

Section: Resultsmentioning

confidence: 55%

“…Figure 7 displays the J-E data for n-InP anodes in contact with KCl(aq)-0.100 M Fe(CN) 6 4--0.100 M Fe(CN) 6 3-. When compared to data on n-InP/CH 3 OH-Me 2 -Fc +/0 contacts studied previously 69 and reevaluated in the course of this work (Figure 7a), the current densities in Figure 7b were Although the short-circuit current density was zero at n-InP/ CH 3 OH/Me 2 Fc +/0 contacts, a nonzero short-circuit current density of 0.5 µA cm -2 was observed for n-InP/KCl(aq)-Fe-(CN) 6 3-/4-junctions. The presence of a finite current density at short circuit indicated the presence of a chemical passivation or corrosion reaction at the n-InP/KCl(aq)-Fe(CN) 6 3-/4-contact.…”

Section: Barrier Height Measurements and Upper Bounds On K Et For mentioning

confidence: 99%

Theoretical and Experimental Upper Bounds on Interfacial Charge-Transfer Rate Constants between Semiconducting Solids and Outer-Sphere Redox Couples

1996

Self Cite

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Theoretical expressions for the charge-transfer rate constant at a semiconductor/liquid junction have been modified to include the effects of adiabaticity and the existence of a Helmholtz layer at the solid/liquid interface. These expressions have yielded an estimate of the maximum interfacial charge-transfer rate constant, at optimal exoergicity, for a semiconductor in contact with a random distribution of nonadsorbing, outer-sphere redox species. An experimental upper bound on this interfacial charge-transfer rate constant has been obtained through the determination of key energetic and kinetic properties for stable semiconductor electrodes in contact with outer-sphere redox species. For this purpose, n-Si/CH 3 OH-dimethylferrocenium-dimethylferrocene, n-GaAs/CH 3 CN-ferrocenium-ferrocene, and p-InP/CH 3 CN-cobaltocenium-cobaltocene contacts were investigated using a combination of current density-potential and differential capacitance-potential methods. The upper limits for the interfacial charge-transfer rate constant at these semiconductor/liquid contacts were found to be consistent with the upper limits predicted by theory. The current density-potential behavior of n-InP and p-InP/Fe(CN) 6 3-/4-(aq) junctions was also examined in order to assess the validity of prior kinetic measurements on these interfaces.

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“…17 In fact, the early studies that characterized electron transfer across the Si-solution interface required dry, non-aqueous solvents and many were performed in inert atmospheres. [18][19][20] A number of approaches have been developed to protect the interface including employing ultrathin oxides, [21][22][23][24] 1-and 2D materials, [25][26][27] wet-chemical functionalization, 28 and continuous thin metal films. [29][30][31] A second major barrier for LAES is that close electronic coupling between the Si surface and the redox couple is required for efficient electron transfer.…”

Section: Methodsmentioning

confidence: 99%

Light-Addressable Electrochemical Sensing of Dopamine Using on N-Silicon/gold Schottky Junctions

Rodríguez¹,

Borrill²,

O’Neil

2019

Preprint

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Here, we report the use of semiconductor/metal (Schottky) junctions as light-addressable electrochemical sensors (LAES). We employ an n-Si/Au Schottky junction prepared by electrodeposition of Au nanoparticles (NPs) on a freshly etched n-Si photoelectrode. The sensors demonstrate near reversible electrochemical behavior for the oxidation of ferrocene methanol and potassium ferrocyanide. Moreover, n-Si/Au LAES were stable for 1000 cyclic voltammetry cycles in an aqueous electrolyte – even though the n-Si surface was only partially covered with Au NPs. We also challenged the LAES to detect the neurotransmitter dopamine and found that the sensors were quantitative over the range from 15-500 µM in buffer. We used local illumination to generate a virtual array of electrochemical sensors for dopamine as a strategy for circumventing sensor fouling.

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Efficient photovoltaic devices for InP semiconductor/liqud junctions

Cited by 21 publications

References 25 publications

Unique Three-Dimensional InP Nanopore Arrays for Improved Photoelectrochemical Hydrogen Production

Unique Three-Dimensional InP Nanopore Arrays for Improved Photoelectrochemical Hydrogen Production

Theoretical and Experimental Upper Bounds on Interfacial Charge-Transfer Rate Constants between Semiconducting Solids and Outer-Sphere Redox Couples

Light-Addressable Electrochemical Sensing of Dopamine Using on N-Silicon/gold Schottky Junctions

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