Water splitting with silicon p–i–n superlattices suspended in solution

Teitsworth, Taylor S.; Hill, David J. T.; Litvin, Samantha R.; Ritchie, Earl T.; Park, Jin-Sung; Custer, James; Taggart, Aaron D.; Bottum, Samuel R.; Morley, Sarah E.; Kim, Seokhyoung; McBride, James R.; Atkin, Joanna M.; Cahoon, James F.

doi:10.1038/s41586-022-05549-5

Cited by 51 publications

(25 citation statements)

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“…From an analytical point of view, although we have demonstrated it on these specifically tailored Au-pnn ++ Si-Pt devices, this strategy should be also effective with other photoelectrochemical devices, such as nanostructured photoelectrodes, 49−51 semiconductor photocatalysts, 52,53 or artificial leaves, 54,55 and can play a relevant role in elucidating energy conversion mechanisms at the nanoscale. Finally, due to its alloptical nature, the simplicity and versatility of the reported approach should extend this powerful technique to nonspecialists.…”

Section: Discussionmentioning

confidence: 99%

All-Optical Electrochemiluminescence

et al. 2023

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Electrochemiluminescence (ECL) is widely employed for medical diagnosis and imaging. Despite its remarkable analytical performances, the technique remains intrinsically limited by the essential need for an external power supply and electrical wires for electrode connections. Here, we report an electrically autonomous solution leading to a paradigm change by designing a fully integrated alloptical wireless monolithic photoelectrochemical device based on a nanostructured Si photovoltaic junction modified with catalytic coatings. Under illumination with light ranging from visible to nearinfrared, photogenerated holes induce the oxidation of the ECL reagents and thus the emission of visible ECL photons. The blue ECL emission is easily viewed with naked eyes and recorded with a smartphone. A new light emission scheme is thus introduced where the ECL emission energy (2.82 eV) is higher than the excitation energy (1.18 eV) via an intermediate electrochemical process. In addition, the mapping of the photoelectrochemical activity by optical microscopy reveals the minority carrier interfacial transfer mechanism at the nanoscale. This breakthrough provides an all-optical strategy for generalizing ECL without the need for electrochemical setups, electrodes, wiring constraints, and specific electrochemical knowledge. This simplest ECL configuration reported so far opens new opportunities to develop imaging and wireless bioanalytical systems such as portable point-of-care sensing devices.

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Section: Discussionmentioning

confidence: 99%

All-Optical Electrochemiluminescence

et al. 2023

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“…Moreover, the Si NW GSLs demonstrated herein offer a versatile platform for the design of more complex structures and active electronic devices using a bottom-up growth process. For example, p – i – n superlattices can be encoded within a Si NW GSL, , enabling photodetection and static electric field effects − to be explored on conjunction with quasi -BIC resonances. We believe that this study represents a meaningful step toward the development of nonlinear subwavelength light sources.…”

Section: Discussionmentioning

confidence: 99%

Optical Nonlinearity in Silicon Nanowires Enabled by Bound States in the Continuum

Park

Kim

et al. 2023

ACS Nano

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Intense electromagnetic fields localized within resonant photonic nanostructures provide versatile opportunities for engineering nonlinear optical effects on a subwavelength scale. For dielectric structures, optical bound states in the continuum (BICs, resonant nonradiative modes that exist within the radiation continuum) are an emerging strategy to localize and intensify fields. Here, we report efficient second and third harmonic generation from Si nanowires (NWs) encoded with BIC and quasi-BIC resonances. In situ dopant modulation during vapor−liquid−solid NW growth was followed by wet-chemical etching to periodically modulate the diameter of the Si NWs and create cylindrically symmetric geometric superlattices (GSLs) with precisely defined axial and radial dimensions. By variation of the GSL structure, BIC and quasi-BIC resonant conditions were created to span visible and near-infrared optical frequencies. To probe the optical nonlinearity of these structures, we collected linear extinction spectra and nonlinear spectra from single-NW GSLs, demonstrating that quasi-BIC spectral positions at the fundamental frequency are directly correlated with enhanced harmonic generation at second and third harmonic frequencies. Interestingly, we find that deliberate geometric detuning from the BIC condition leads to a quasi-BIC resonance with maximal harmonic generation efficiency by providing a balance between the capacity to trap light and the capacity to couple to the external radiation continuum. Moreover, under focused illumination, as few as 30 geometric unit cells are required to achieve more than 90% of the approximate maximum theoretical efficiency of an infinite structure, indicating that nanostructures with projected areas smaller than ∼10 μm 2 can support quasi-BICs for efficient harmonic generation. The results represent an important step toward the design of efficient harmonic generation at the nanoscale and further highlight the photonic utility of BICs at optical frequencies in ultracompact one-dimensional nanostructures.

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“…Although the electric field set up in the system is critical to achieve spatial separation of photoexcited charges, the obtained STH efficiency is still much lower than that of recent progress in photocatalytic systems comprising high-quality p–n homo- and heterojunctions. , In these systems, besides the built-in electric fields, the wide-spectrum absorption of light absorbers in tandem with high-quality interfaces is another key factor to achieve high efficiency.…”

Section: Conclusion and Perspectivementioning

confidence: 98%

PbTiO₃ Based Single-Domain Ferroelectric Photocatalysts for Water Splitting

et al. 2023

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Metrics & MoreArticle Recommendations CONSPECTUS: Solar-driven photocatalytic water splitting paves a way to produce green hydrogen for building a sustainable clean energy system, particularly within the framework of the carbon-neutral initiative. However, to date, the solar-to-hydrogen (STH) conversion efficiency of particulate photocatalysts falls far short of the demand of over 10% for industrial applications. Single-domain ferroelectric semiconductor materials with amazing unidirectional spontaneous polarization penetrating the bulk are promising candidates as photocatalysts for water splitting. Their existing inherent internal field set up by polarization can cause both two oppositely charged surfaces (namely, polar surfaces) and spatial separation of photogenerated charge carriers between them upon light excitation. These unique properties provide sufficient new room for flexibly engineering of bulk and surface/interface structures to enhance photocatalytic water splitting.In this Account, we offer a systematic overview of the exploration of PbTiO 3 based singledomain ferroelectric photocatalysts for efficient solar water splitting. In detail, the controlled growth, surface modification, heterostructures, and Z-scheme system of single-domain PbTiO 3 ferroelectrics are discussed by considering polar surfaces, spatial separation of the photoexcited charges, selective distribution of defects, and selective adsorption of reactive species. We start with the controlled synthesis of single-domain ferroelectric PbTiO 3 nanoplates to realize the opposite directional transport of photoexcited charges driven by the polarized internal electric field, which can be verified by the fact that photochemical reduction/oxidation deposits occur on opposite polar surfaces. Then, we move to the selective modification of the specific polar surface to promote the transfer of photoexcited charges by applying the spatial separation effect of photoexcited charges and defects related internal screening mechanism. Furthermore, asymmetric heterostructures and Z-scheme systems are rationally designed by selective adsorption of reactive species on charged surfaces to promote charge separation and suppress redox mediator side reactions, respectively. Although significant advances have been achieved, many efforts remain needed toward the industrial production target. Based on single-domain ferroelectric photocatalysts, we present the following perspectives on the utilization of a wide solar spectrum for improving solar energy conversion efficiency. First, proper dopants can be incorporated homogeneously in the bulk to reduce the bandgap without obviously weakening ferroelectricity. Second, the epitaxial growth of narrow bandgap semiconductors on the ferroelectrics is feasible to induce additional polarization in the region close to their interface. These two aspects are anticipated to enable strong visible light absorption and charge separation efficiency. Third but not least, the assembly of Z-scheme systems with two narrow bandgap ferroel...

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Water splitting with silicon p–i–n superlattices suspended in solution

Cited by 51 publications

References 40 publications

All-Optical Electrochemiluminescence

All-Optical Electrochemiluminescence

Optical Nonlinearity in Silicon Nanowires Enabled by Bound States in the Continuum

PbTiO₃ Based Single-Domain Ferroelectric Photocatalysts for Water Splitting

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Water splitting with silicon p–i–n superlattices suspended in solution

Cited by 51 publications

References 40 publications

All-Optical Electrochemiluminescence

All-Optical Electrochemiluminescence

Optical Nonlinearity in Silicon Nanowires Enabled by Bound States in the Continuum

PbTiO3 Based Single-Domain Ferroelectric Photocatalysts for Water Splitting

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Product

Resources

About

PbTiO₃ Based Single-Domain Ferroelectric Photocatalysts for Water Splitting