Magnetron sputtered Cu doped SnS thin films for improved photoelectrochemical and heterojunction solar cells

Pati

Marathey

et al. 2016

J. Electrochem. Soc.

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Tenorite CuO thin films have been synthesized via spray pyrolysis of aqueous copper(II) chloride solution followed by heat-treatment, exhibited a photocurrent density of 24 mA cm −2 at 0.25 V vs. RHE under AM 1.5G solar irradiation in alkaline electrolyte. This large photocurrent density has been attributed to a drift assisted transport of photo-generated electrons across the semiconductor/electrolyte interface in the annealed films. The tendency of photo-corrosion from the surface of CuO has been reduced substantially without any extra protective layer, simply by adding K 3 Fe(CN) 6 in the electrolyte, which acts as a sacrificial excess-electron scavenging agent. The fabricated electrode exhibited a positive onset potential at 0.25 V vs. RHE even after the electrolyte modification and a stable photocurrent density of more than 40% has been retained after 20 minutes of continuous illumination. The processed photocathode showed a solar to chemical conversion efficiency of 7.85% and 21.5% with and without using an electron scavenging agent, respectively. It holds the promise of using this photocathode in PEC energy conversion, photocatalysis and solar water splitting.In the exploration of terrestrially employable carbon-free energy sources, materials play a central role in the generation and storage of electrical as well as chemical energies. 1,2 Semiconducting materials are especially important to harvest the solar energy due to their bandgap energies matching to that of the visible photons. Photovoltaic (PV) and photoelectrochemical (PEC) methods are the two solar energy conversion modes those utilize semiconductor materials. In order to apply semiconductors in PEC applications, three important aspects must be satisfied: first, capability of providing large photocurrent density; second, a long term stability; and third, the scalability. 3 Several semiconductors, such as have been explored in the PEC applications with majority as catalysts for water splitting. The hunt for novel structure and materials design thus continues to set off the above requirements. Oxides of copper (CuO and Cu 2 O) have recently drawn special attention due to their relative abundance on the earth crust. Majority of the recently reported investigations are focused on Cu 2 O. [25][26][27][28][29][30][31][32] Due to the chemical instability and poor electron transfer, its nano-composites with other oxides or metal catalysts have been attempted. [33][34][35] On the other hand, CuO is chemically more stable than Cu 2 O but there are only few studies on the PEC response of CuO have been reported so far. 36 Among various oxides of copper (viz. Cu 2 O, CuO and Cu 4 O 3 ), tenorite CuO is a chemically stable p-type semiconductors having an indirect bandgap in the range of 1.3-1.7 eV. 37-42 This property makes CuO a promising candidate for solar to chemical energy conversion with maximum possible theoretical photocurrent density in the range of 22-35 mAcm −2 under standard AM 1.5G solar irradiance corresponding to its high and low bandgap values, ...

Section: Resultsmentioning

confidence: 99%

Highly Photoactive and Photo-Stable Spray Pyrolyzed Tenorite CuO Thin Films for Photoelectrochemical Energy Conversion

Pati

Marathey

et al. 2016

J. Electrochem. Soc.

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“…The NiO material was found to have cubic crystal symmetry with space groups of Fm‐3m (225) according to COD‐AMSCD 9008693. The XRD data were processed as described elsewhere . The background‐corrected XRD pattern of all NiO films revealed 2 θ peaks at 37.35°, 43.4°, 63.06°, 75.5°, and 79.55°, corresponding to the (111), (002), (022), (113), and (222) planes.…”

Section: Resultsmentioning

confidence: 99%

All Transparent Metal Oxide Ultraviolet Photodetector

Kim

2015

Adv Elect Materials

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141

A high‐performing UV photodetector that uses large energy bandgap materials of p‐type NiO and n‐type ZnO without an opaque metal electrode is reported. A quality heterojunction is formed by large‐area applicable sputtering deposition method that has an extremely low saturation current density of 0.1 μA cm−2. This abrupt p‐NiO/n‐ZnO heterojunction device is visible‐light transparent and shows the fastest photoresponse time of 24 ms among NiO‐based UV photodetectors, along with the highest responsivity (3.85 A W−1) and excellent detectivity (9.6 × 1013 Jones) properties. Structural, physical, optical, and electrical properties of nanocrystalline NiO are systematically investigated. Mott–Schottky analyses are applied to develop the interface of NiO and ZnO by establishing energy diagrams. Defects existing inside the nanocrystalline NiO film enhance the UV detection performance by defect‐assisted carrier transportation. The results provide a solid scheme of manipulation of NiO defects for functional photoelectric device applications.

“…However, many synthetic methods produce mixtures of SnS particles in different phases such as zinc‐blend, cubic and orthorhombic structures, which fact explains an inherent complexity associated with the Sn and S chemistry . Purification and crystallization of the pristine SnS particles require additional post‐processes such as post‐annealing, elemental sulfurization and H 2 S treatments . Post‐treated commercial SnS powder based solar cell exhibited the power conversion efficiency of 3.88 % .…”

Section: Introductionmentioning

confidence: 99%

“…[31] Purification and crystallization of the pristine SnS particles require additional post-processes such as post-annealing, elemental sulfurization and H 2 St reatments. [7,29,32,33] Post-treated commercial SnS powderb ased solar cell exhibited the powerc onversion efficiency of 3.88 %. [7] Even higher efficiency of 4.4 %h as been obtained from aS nS-based solar cell prepared by atomicl ayer deposition (ALD).…”

Section: Introductionmentioning

confidence: 99%

Facile Formation of Nanodisk‐Shaped Orthorhombic SnS Layers from SnS₂ Particles for Photoelectrocatalytic Hydrogen Production

Kim

et al. 2017

ChemNanoMat

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SnS has a great potential for use as a photocatalyst for the production of chemical fuels out of sunlight. For the use of it as a photocatalyst, a fast and reliable method of fabricating pure layered crystalline SnS is required. Here, we present a simple and efficient method of fabricating high‐quality SnS layers as a thin film on various substrates such as Si, quartz, glass and FTO. The nanodisk‐shaped p‐type SnS films are obtained starting from SnS2 via a one‐step process involving phase dissociation and sulfur reduction. The prepared SnS films show interesting thickness‐dependent physical properties such as optical band gap, absorption coefficient and flat band potential, which suggest the possibility of tuning its property by controlling the thickness. Especially, the SnS films with the thickness of 20 nm or less show an enhanced absorption above the band gap and an increased free carrier concentration. With such advantageous photoresponsive properties, we observed a good hydrogen production activity (order of 100 μmol h−1 cm−2) from the thin SnS films under photoelectrocatalytic reaction conditions. The measured efficiency in hydrogen evolution is explained from a favorable band alignment as well as the good photoresponse of the film. Combined with the facile fabrication of high‐quality thin SnS films, our analysis shows that nanodisk‐shaped SnS is a promising material for a future development of photocatalytic production of hydrogen as a chemical fuel.