Interface Engineering for High‐Performance Photoelectrochemical Cells via Atomic Layer Deposition Technique

Cao, Shiyao; Zhang, Zheng; Liao, Qingliang; Kang, Zhuo; Zhang, Yue

doi:10.1002/ente.202000819

Cited by 5 publications

(2 citation statements)

References 128 publications

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“…Since this work, many protective insulators have been utilized in Si-based MIS photocatalysts, including Al 2 O 3 , − HfO 2 , − SiO 2 , − SrTiO 3 , TiO 2 , ,− and ZrO 2 . The widespread deployment of these insulators was enabled by atomic layer deposition (ALD), which is a layer-by-layer growth technique to deposit conformal and pinhole-free layers of materials with sub-nanometer precision. ,,,− …”

Section: Introductionmentioning

confidence: 99%

Design Principles for Efficient and Stable Water Splitting Photoelectrocatalysts

2021

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Conspectus Photoelectrochemical water splitting is a promising avenue for sustainable production of hydrogen used in the chemical industry and hydrogen fuel cells. The basic components of most photoelectrochemical water splitting systems are semiconductor light absorbers coupled to electrocatalysts, which perform the desired chemical reactions. A critical challenge for the design of these systems is the lack of stability for the majority of desired semiconductors under operating water splitting conditions. One strategy to address this issue is to protect the semiconductor by covering it with a stabilizing insulator layer, creating a metal–insulator–semiconductor (MIS) architecture, which has demonstrated improved stability. In addition to enhanced stability, the insulator layer may significantly affect the electron and hole transfer, which governs the recombination rates. Furthermore, the insertion of an insulator layer leads to the introduction of additional insulator/electrocatalyst and insulator/semiconductor interfaces. These interfaces can impact the system’s performance significantly, and they need to be carefully engineered to optimize the efficiencies of MIS systems. In this Account, we describe our recent progress in shedding light on the critical role of the insulator and the interfaces on the performance of MIS systems. We discuss our findings by focusing on the concrete example of planar n-type Si protected by a HfO2 insulator layer and coupled to a Ni or Ir electrocatalyst that performs the oxygen evolution reaction, one of the water splitting half-reactions. To improve our fundamental understanding of the insulator layer, we precisely control the HfO2 insulator thickness using atomic layer deposition (ALD), and we perform a series of rigorous electrochemical experiments coupled with theory and modeling. We demonstrate that by tuning the insulator thickness, we can control the flux and recombination of photogenerated electrons and holes to optimize the generated photovoltage. Despite optimizing the thickness, we find that the maximum generated photovoltage in MIS systems is often significantly lower than the upper performance limit, i.e., there are additional losses in the system that could not be addressed by optimizing the insulator thickness. We identify the sources of these losses and describe strategies to minimize them by a combination of improving the semiconductor light absorption, removing nonidealities associated with interfacial defects, and finding alternative insulators with improved charge carrier selectivity. Finally, we quantify the improvements that can be obtained by implementing these specific strategies. Our collective work outlines strategies to analyze MIS systems, identify the sources of efficiency losses, and optimize the design to approach the fundamental performance limits. These general approaches are broadly applicable to photoelectrochemical materials that utilize sunlight to produce value-added chemicals.

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Section: Introductionmentioning

confidence: 99%

Design Principles for Efficient and Stable Water Splitting Photoelectrocatalysts

2021

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“…The performance of nanoparticle electrocatalyst/semiconductor (np-EC/SC) photoelectrocatalysts is largely governed by the interface between the semiconductor and the electrocatalyst as it governs the transfer of photo-excited electrons and holes from the semiconductor to the electrocatalyst and therefore the generated photovoltage which is one of the key performance metrics for solar water splitting performance. [4][5][6][7][8][9] Despite the pivotal role of the np-EC/SC interface, its physical and chemical properties are poorly understood and difficult to characterize. The challenge is that the interface is complex on atomic scales and inaccessible to direct experimental probes.…”

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confidence: 99%

Characterizing the Geometry and Quantifying the Impact of Nanoscopic Electrocatalyst/Semiconductor Interfaces under Solar Water Splitting Conditions

Hemmerling

Mathur

Linic

2022

Advanced Energy Materials

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The materials that are receiving the most attention in photoelectrochemical water splitting are metallic nanoparticle electrocatalysts (np‐EC) attached to the surface of a semiconductor (SC) light absorber. In these multicomponent systems, the interface between the semiconductor and electrocatalysts critically affects performance. However, the np‐EC/SC interface remains poorly understood as it is complex on atomic scales, dynamic under reaction conditions, and inaccessible to direct experimental probes. This contribution sheds light on how the electrocatalyst/semiconductor interface evolves under reaction conditions by investigating the behavior of nickel electrocatalysts (as nanoparticles and films) deposited on silicon semiconductors. Rigorous electrochemical experiments, interfacial atomistic characterization, and computational modeling are combined to demonstrate critical links between the atomistic features of the interface and the overall performance. It is shown that electrolyte‐induced atomistic changes to the interface lead to (1) modulation of the charge carrier fluxes and a dramatic decrease in the electron/hole recombination rates and (2) a change in the barrier height of the interface. Furthermore, the critical roles of nonidealities and electrocatalyst coverage due to interfacial geometry are explored. Each of these factors must be considered to optimize the design of metal/semiconductor interfaces which are broadly applicable to photoelectrocatalysis and photovoltaic research.

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Particle‐Based Photoelectrodes for PEC Water Splitting: Concepts and Perspectives

Liu,

Kuang

2024

Advanced Materials

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This comprehensive review delves into the intricacies of the photoelectrochemical (PEC) water splitting process, specifically focusing on the design, fabrication, and optimization of particle‐based photoelectrodes for efficient green hydrogen production. These photoelectrodes, composed of semiconductor materials, potentially harness light energy and generate charge carriers, driving water oxidation and reduction reactions. The versatility of particle‐based photoelectrodes as a platform for investigating and enhancing various semiconductor candidates is explored, particularly the emerging complex oxides with compelling charge transfer properties. However, the challenges presented by many factors influencing the performance and stability of these photoelectrodes, including particle size, shape, composition, morphology, surface modification, and electrode configuration, are highlighted. The review introduces the fundamental principles of semiconductor photoelectrodes for PEC water splitting, presents an exhaustive overview of different synthesis methods for semiconductor powders and their assembly into photoelectrodes, and discusses recent advances and challenges in photoelectrode material development. It concludes by offering promising strategies for improving photoelectrode performance and stability, such as the adoption of novel architectures and heterojunctions.This article is protected by copyright. All rights reserved

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Interface Engineering for High‐Performance Photoelectrochemical Cells via Atomic Layer Deposition Technique

Cited by 5 publications

References 128 publications

Design Principles for Efficient and Stable Water Splitting Photoelectrocatalysts

Design Principles for Efficient and Stable Water Splitting Photoelectrocatalysts

Characterizing the Geometry and Quantifying the Impact of Nanoscopic Electrocatalyst/Semiconductor Interfaces under Solar Water Splitting Conditions

Particle‐Based Photoelectrodes for PEC Water Splitting: Concepts and Perspectives

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