Two dimensional tin sulfide for photoelectric device

Malkeshkumar Patel,Joondong Kim 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.2

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

Patel, Malkeshkumar,Pati, Ranjan,Marathey, Priyanka,Kim, Joondong,Mukhopadhyay, Indrajit,Ray, Abhijit The Electrochemical Society 2016 Journal of the Electrochemical Society Vol.163 No.14

<P>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 AM1.5G 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 K3Fe(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. (C) 2016 The Electrochemical Society. All rights reserved.</P>

High-performing flexible and transparent photodetector by using silver nanowire-networks

Patel, Dipal B.,Patel, Malkeshkumar,Chauhan, Khushbu R.,Kim, Joondong,Oh, Min Suk,Kim, Jong-Woong Elsevier 2018 Materials research bulletin Vol.97 No.-

<P><B>Abstract</B></P> <P>Transparent and flexible photodetector was realized by effective interfacial design methods. Silver nanowires (AgNWs) were networked onto a colorless polyimide (cPI) substrate to ensure the transparent conductive front electrode of Ni/ZnO/AgNWs/cPI photodetector. Under UV illumination, remarkable performances were obtained for quick responses (rise time=0.987ms and fall time=2.49ms) and ultrahigh responsivity (1.46×10<SUP>4</SUP> A/W). Due to the merit of AgNW-networks, an enhanced interfacial surface was established for the ZnO film, simultaneously providing efficiently short pathways for the collection of photo-generated carriers. The AgNWs-embedding Schottky photodetector gave an excellent noise equivalent power of 4.38×10<SUP>−15</SUP> W/Hz<SUP>1/2</SUP>, which is suitable for femtowatt-level photodetection. We demonstrate that the active adoption of metallic nanowires would provide high-degree of freedom for high-performing photoelectric devices with satisfying flexible and transparent features.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Flexible and transparent Ni/ZnO/AgNWs/cPI photodetector was achieved. </LI> <LI> AgNW-networks provide the enhanced interfacial surface for effective charge collection. </LI> <LI> Ultrahigh responsivity (1.46×10<SUP>4</SUP> A/W) by using AgNW-networked photodetector. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nanostructured SnS with inherent anisotropic optical properties for high photoactivity

Patel, Malkeshkumar,Chavda, Arvind,Mukhopadhyay, Indrajit,Kim, Joondong,Ray, Abhijit The Royal Society of Chemistry 2016 Nanoscale Vol.8 No.4

<P>In view of the worldwide energy challenge in the 21<SUP>st</SUP>century, the technology of semiconductor-based photoelectrochemical (PEC) water splitting has received considerable attention as an alternative approach for solar energy harvesting and storage. Two-dimensional (2D) structures such as nanosheets have the potential to tap the solar energy by unlocking the functional properties at the nanoscale. Tin(ii) sulfide is a fascinating solar energy material due to its anisotropic material properties. In this manuscript, we report on exploiting the 2D structure modulated optical properties of nanocrystalline SnS thin film synthesized by chemical spray pyrolysis using ambient transport in the harvesting of solar energy. We obtained the nanostructured SnS with well-preserved dimensions and morphologies with one step processing. The work demonstrates that the intrinsically ordered SnS nanostructure on FTO coated glass can tap the incident radiation in an efficient manner. The structure-property relationship to explain the photo-response in nanocrystalline-SnS is verified experimentally and theoretically. The novel design scheme for antireflection coating along with the anisotropic properties of SnS is conceived for realizing a PEC cell. The developed PEC cell consists of a SnS photoanode which shows considerably high photocurrent density of 7 mA cm<SUP>−2</SUP>with aqueous media under AM 1.5G, 100 mW cm<SUP>−2</SUP>exposure with notably stable operation. Electrochemical impedance spectroscopy revealed that a non-ideal capacitive behavior as well as drift assisted transport across the solid-state interface is responsible for such a high photo-current density in the nanocrystalline-SnS photoanode.</P>

AgNWs networks for high-performing transparent heaters by using NiO window layer

Patel, Malkeshkumar,Chauhan, Khushbu R.,Kim, Joondong,Kim, Jong-Woong,Lim, Donggun Elsevier 2017 Sensors and actuators. A, Physical Vol.267 No.-

<P><B>Abstract</B></P> <P>We demonstrate the high-performing silver nanowire (AgNW) networks for transparent heaters by using a NiO window layer. The colorless polyimide (cPI) was used as a substrate in order to configure the transparent heater of NiO/AgNWs/cPI, having over 77% transmittance at a wavelength of 550nm. AgNWs networks were formed on the cPI substrate and the NiO layer was reactively sputtered onto AgNWs at a room temperature. Due to the NiO capping layer onto AgNWs, the electrical and optical properties of AgNW networks were preserved. An extremely high-performing AgNWs-based transparent heater was achieved by utilizing NiO protective. The NiO window layer provides an excellent atmospheric isolation for partially-embedded silver nanowires and makes the heater operation to be stable at high temperatures of 185.5°C with a relatively small bias of 7V. The excellent performances are attributed to the Schottky barrier formed between the NiO window and AgNW networks. The efficient exploitation of capping layers, such as NiO in this study will boost the viability of AgNW-based heaters and electronic devices for commercial applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High-performing transparent heater was formed by AgNWs and NiO layer. </LI> <LI> NiO layer efficiently protected AgNWs from deformation. </LI> <LI> NiO functional window effectively controlled the electrical and thermal properties. </LI> <LI> 200°C was reached by applying 7V for stable operation. </LI> </UL> </P>

Proximity Vapor Transfer for Wafer-Scale SnS Semiconductors for Transparent Photovoltaics

PATEL MALKESHKUMAR PRAVINBHAI,김준동 한국진공학회 2021 한국진공학회 학술발표회초록집 Vol.2021 No.2

The 2D semiconductors, enhanced light absorption and fast speed of charges, can be applied to transparent photovoltaics (TPV). We explored the wafer-scale 2D-SnS in nanoplatelets geometry to TPV and broadband photodetector. Confined tin and sulfur vapors between a solid SnS source and variable substrates in close proximity originate the S-rich SnS nanoplatelets. The TPV cell with SnS via proximity vapor transfer demonstrates stable and balanced light-matter interaction, a visible transmission of 60%, an open-circuit voltage of 0.7 V, and output power of 6 mW by a 60mW light.

Transparent NiO/ZnO heterojunction for ultra-performing zero-bias ultraviolet photodetector on plastic substrate

Patel, Malkeshkumar,Kim, Joondong Elsevier 2017 Journal of alloys and compounds Vol.729 No.-

<P><B>Abstract</B></P> <P>All transparent photoelectric devices were achieved for the highly-performing photodetectors. The high transparent heterojunction photodetector of the configuration of NiO/ZnO/ITO/PET was realized by using the solid-state sputtering method. All metal oxide layers were formed at room temperature to be applied on the plastic substrate. The ITO layer was directly coated on the PET substrate to work as a transparent conductor. To form the transparent p/n junction, p-type NiO was reactively sputtered following by n-type ZnO deposition onto the ITO. This high visible-range transparent (74.8%) photodetector is extremely sensitive to detect the tiny UV light density of 10 μW/cm<SUP>2</SUP> with the ultra-fast photoresponse time (19 μs) and high-photoresponse ratio (1944) due to the merit of excitonic absorption. The design scheme of zero-bias operating transparent heterojunction can be applied for visible electronic devices and solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> High transparent (74.8%) and ultra-performing photodetector was achieved. </LI> <LI> All metal oxides were deposited on a plastic substrate at room temperature. </LI> <LI> Heterojunction photodetector is configuring of p-type NiO and n-type ZnO. </LI> <LI> Record-fast photoresponse 19 μs was achieved by self-operating mode. </LI> </UL> </P>

Photoelectrocatalytic sea water splitting using Kirkendall diffusion grown functional Co₃O₄ film

Patel, Malkeshkumar,Park, Wang-Hee,Ray, Abhijit,Kim, Joondong,Lee, Jung-Ho North-Holland 2017 Solar Energy Materials and Solar Cells Vol. No.

<P><B>Abstract</B></P> <P>Earth-abundant, non-toxic, and stable porous Co<SUB>3</SUB>O<SUB>4</SUB> film grown by Kirkendall-diffusion is developed for efficient photoelectrocatalytic seawater splitting. Semitransparent Co<SUB>3</SUB>O<SUB>4</SUB> films are found highly active hydrogen evolution reaction (HER) photocatalyst with stable performances. Dual band gap (1.5eV and 2.3eV) p-type Co<SUB>3</SUB>O<SUB>4</SUB> samples exhibiting photo induced HER current density of 25mA/cm<SUP>2</SUP> is obtained with overpotential of 0.83V in the sea-water. Our Co<SUB>3</SUB>O<SUB>4</SUB> sample possesses Tafel slope of 20mV/dec, incident photon to the current conversion efficiency of > 8%, and charge transfer resistance of 3.4Ω/cm<SUP>2</SUP>. Photo induced Mott-Schottky analysis was applied to find the flat band potential corresponding to the lower band gap value and exhibited strong influence on the majority carrier concentrations and shifting of flat band potential. Electrical properties of Co<SUB>3</SUB>O<SUB>4</SUB> material and losses associated in seawater splitting were carefully studied using the Mott-Schottky and electrochemical impedance spectroscopy. Present studies on seawater splitting using Co<SUB>3</SUB>O<SUB>4</SUB> not only suggest photoelectrocatalytic hydrogen generation but also usefulness for efficient sea salts formation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Semitransparent Co<SUB>3</SUB>O<SUB>4</SUB> film is grown by the Kirkendall-diffusion. </LI> <LI> Co<SUB>3</SUB>O<SUB>4</SUB> is capable to photoinduced seawater splitting for hydrogen generation. </LI> <LI> Porous Co<SUB>3</SUB>O<SUB>4</SUB> film to enable IPCE more than 8% at over potential of 0.83V. </LI> <LI> Dual energy gaps of Co<SUB>3</SUB>O<SUB>4</SUB> are determined using Mott-Schottky analysis. </LI> <LI> Stable photoelectrolysis seawater splitting (J = 25mA/cm<SUP>2</SUP>, η = 0.8V) is exhibited. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Transparent all-oxide photovoltaics and broadband high-speed energy-efficient optoelectronics

Patel, Malkeshkumar,Ban, Dong-Kyun,Ray, Abhijit,Kim, Joondong Elsevier 2019 Solar energy materials and solar cells Vol.194 No.-

<P><B>Abstract</B></P> <P>Heterostructure of wide-bandgap materials have great potential for use in transparent optoelectronics for examples ultraviolet photodetectors, transparent solar cells, and transparent electronics. This study demonstrates the exciton, band-to-band and intermediate-band optical transitions in a ZnO/NiO heterostructure at room temperature. This heterostructure exhibits Ohmic current-voltage characteristics close to that of various metal contacts such as Ag, C, Ni, and Au. Temperature-dependence studies revealed that the open-circuit voltage (V<SUB>OC</SUB>) of ZnO/NiO heterostructure is limited by the charge-transfer potential, analogous to excitonic solar cells. A negligibly small dark current of 1.6 × 10<SUP>−8</SUP> A, a large V<SUB>OC</SUB> of 675 mV and a photoresponse speeds of 9.4 μs make it promising for high-speed energy-efficient optoelectronics. The optoelectronic performances of the ZnO/NiO/Ag microink suggest that broadband photons can be utilized with incident photons to current conversion efficiencies (IPCEs) of 2% and 39% in the visible and ultraviolet regions, respectively which demonstrate that the ZnO/NiO heterostructure can acts as a broadband quantum optoelectronic device.</P> <P><B>Highlights</B></P> <P> <UL> <LI> All transparent oxide photovoltaic is realized by ZnO/NiO heterostructure. </LI> <LI> Optical transitions found in a ZnO/NiO heterostructure at room temperature. </LI> <LI> ZnO/NiO heterostructure can acts as a broadband quantum optoelectronic device. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Transparent Photovoltaic System for Efficient Energy Management

Malkeshkumar Patel(말케시 쿠마 파텔),Joondong Kim(김준동) 한국태양에너지학회 2021 한국태양에너지학회 학술대회논문집 Vol.2021 No.11