Thick TiO2 Research Articles

Study on Making a Prototype Dye Sensitized Solar Cell (DSSC) as an Alternative Electric Energy Source

Sunlight as a potential renewable energy source is an ideal solution to meet the increasing electricity needs. Dye Sensitized Solar Cell (DSSC) is an environmentally friendly solar cell because it uses dye organic matter. The purpose of this study was to make a DSSC prototype and examine the effect of dye types and the concentration and thickness of TiO2 layers on the DSSC voltage produced. Solar cells are devices that convert sunlight radiation into electrical energy. Solar cells use a photo-electric effect from semiconductor materials so they can collect solar radiation and convert it into electrical energy. Today, one of the solar cells developed is DSSC which uses electrolytes as an electron transportation medium. DSSC consists of TiO2 nanopores, dye molecules adsorbed on the surface of TiO2, and electrolyte solutions which are all deposited between two conductive glass. In this study, a prototype of DSSC was carried out using organic materials from the extraction of dragon fruit, orange fruits and darker colored mustard greens. Dye extract is adsorbed by TiO2 nanopores which have been deposited into conductive glass (TCO). Carbon is used as a counter-electrode, then an electrolyte solution is added when both conductive glass has been assembled in the form of a sandwich. Based on the experimental results, the greater the concentration of TiO2, the greater the power obtained. The greater the thickness of TiO2, the greater the power obtained, and the variable type of dye that has been studied obtained greater power found in the type of dye from dragon fruit.

A facile route of two-dimensional metal oxide nanosheets fabrication by atomic layer deposition

In this study, two-dimensional nanosheets are fabricated by atomic layer deposition with sacrificial polymers. This method enables to fabricate free thin nanosheets with thickness of nanoscale. In the preparation, TiO2 and ZrO2 metal oxides are deposited onto substrates of Polyacrylic acid and Polyvinyl alcohol acted as sacrificial substrates. By dissolving the substrate, free-thin sheets layer with a high aspect ratio can be achieved due to the exfoliation mechanism. It was shown that the 2D nanosheets can be successfully formed on the deposited ALD material layer which can withstand the emergence of interfacial stress in the region of ALD layer – sacrificial substrate. The achieved nanosheets are characterized by using AFM, which shows that the thickness of both TiO2 and ZrO2 nanosheets are ∼ 80 nm which formed with 1000 and 600 ALD cycles, respectively. The 2D nanosheets obtained in this study have potential applications for photocatalysis, water splitting, and lithium ion battery.

Synthesis of aluminum alloy (AA) based composites TiO2/Al5083 and porphyrin/TiO2/Al5083: Novel photocatalysts for water remediation in visible region

Al5083 is an aluminium alloy with magnesium and traces of manganese and chromium. It is exceedingly resistant to attack by seawater and manufacturing chemicals. In this work, the synthesis of aluminium alloy (AA) based composites TiO2/Al5083 and Porphyrin/TiO2/Al5083 (Porphyrin = Tetrakis(4-carboxyphenyl) porphyrin (TCPP)) has been reported. We employed a chemical etching approach to activate the surface of AA. After the etching process, we successfully coated the TiO2 substrate on the Al5083 surface. In order to investigate the role of TiO2 thickness on photocatalytic efficiency, one, two and three layers of TiO2 were deposited on AA surface and three composites TCPP/TiO2(1)/Al5083, TCPP/TiO2(2)/Al5083 and TCPP/TiO2(3)/Al5083 were produced. We used these AA-composites as the new photocatalysts for degradation of the organic chloride Rhodamine B (RhB) under visible light irradiation. The role of porphyrin sensitizer in the photocatalytic degradation of RhB was investigated as well. The results showed that employing TCPP as a photosensitizer caused the redshift in TiO2/Al5083 absorption spectra reinforcing the photodegradation of RhB. Moreover, TCPP/TiO2(3)/Al5083 composite with three-layers of TiO2 has the highest performance with 29.19 percent of photodegradation efficiency in the visible region.

Controllable Architecture of Mesoporous Double-Nanoshell SiO2/TiO2 Hollow Tube Based on Layer by Layer Method

Double-shell tubular on-dimensional structure can be fabricated through a layer by layer method, in which the core template was removed to create the tubular shape. In this paper, we report, for the first time, the double nanoshell SiO2/TiO2 hollow tubes prepared through a layer-by-layer deposition method involving the sol-gel process for the SiO2 and TiO2 generation. During TEOS and TEOT hydrolysis/condensation for the SiO2 and TiO2 shell layer formation, cetyltrimethylammonium bromide (CTAB) is adopted both as the structure-directing template and as the mesopore-channel template distributing around the shell. The obtained double-nanoshell hollow tubes illustrate a large surface area and high pore volume. Also, mesoporous double-nanoshell SiO2/TiO2 hollow tubes have the inner and outer shell thickness of about 80 nm and 120 nm, respectively. Plus, the shell thickness of SiO2 and TiO2 is controllable depending on the used concentration of TEOS and TEOT during their sol-gel process. Therefore, the technique for the preparation of SiO2/TiO2 mesoporous double-nanoshell hollow tubes could provide new insights into the construction of mesoporous double-shell and hollow structure for other multicomponent and hierarchical hybrid systems.

Optical bandgap control in Al2O3/TiO2 heterostructures by plasma enhanced atomic layer deposition: Toward quantizing structures and tailored binary oxides

Atomically thin heterostructures and superlattices are promising candidates for various optoelectronic and photonic applications. Different combinations of Al2O3/TiO2 composites are obtained by plasma enhanced atomic layer deposition (PEALD). Their growth, composition, dispersion relation, and optical bandgap are systematically studied by means of UV/VIS spectrophotometry, spectroscopic ellipsometry (SE), x-ray reflectometry (XRR), scanning transmission electron microscopy(STEM) and x-ray photoelectron spectroscopy (XPS). Besides, an effective medium approximation (EMA) approach is applied to model the heterostructures theoretically. The refractive index and the indirect bandgap of the heterostructures depend on the ratio of the two oxides, while the bandgap is very sensitive to the thicknesses of the barrier and quantum well layers. A large blue shift of the absorption edge from 400 nm to 320 nm is obtained by changing the TiO2 (quantum well) thickness from ~2 nm to ~0.1 nm separated by ~2 nm of Al2O3 (barrier) layers. PEALD unfolds the possibility of achieving optical quantizing effects within complex heterostructures enabling control of their structures down to atomic scale. It enables a path towards atomic scale processing of new ‘artificial’ materials with desired refractive indices and bandgap combinations by precise control of their compositions.

Constructing ultrathin TiO2 protection layers via atomic layer deposition for stable lithium metal anode cycling

Uncontrollable dendrite growth during the repeated plating/stripping of Li ions induces short cycle life and safety issues, which has severely impeded the practical application of lithium metal battery. It is acknowledged that the solid electrolyte interphase (SEI) is pivotal for Li metal anode stabilization. Here, a lithium metal anode coated with an artificial SEI film as the working electrode is applied. The TiO2 coating layer is firstly demonstrated for the lithium metal anode protection via atomic layer deposition (ALD) method. Thanks to the ultrathin TiO2 layer, dendritic growth is suppressed and the cycling lifetime is significantly improved. Additionally, the thickness of TiO2 protective layer has been further optimized. Comparing with other different thickness TiO2 layer, 5 nm TiO2 layer is found to be the optimized parameter toward capacity, cycling stability and rate capability in both symmetric battery system and full-cell system. The TiO2 layer promoted uniform deposition of Li+ and effectively inhibited the growth of lithium dendrites. Symmetric Li/50TiO2||Li/50TiO2 battery could cycle stably for more than 1600 h at 1 mA cm−2, and more than 500 h at 3 mA cm−2 and 10 mA cm−2 current density. The Li/50TiO2||NCM622 full-cell exhibited better rate performance and long-cycle performance, which capacity retention was increased by 23.3% compared to bare electrode after 100 cycles at 0.5C charge-discharge current density. Furthermore, the inherent working mechanism of TiO2 artificial SEI film has been proposed. This work provides an effective and new alternative method for lithium metal anodes protection, which is critical for the future design of next-generation Li metal batteries under safe operation.

Production of green electricity from strained BaTiO3 and TiO2 ceramics based hydroelectric cells

Electricity generation from water molecules dissociation instantly without use of any chemical/light by invented hydroelectric cell (HEC) has emerged a new field of green energy generation without disturbing the environment. Specially engineered nanoporous and oxygen deficient metal oxides have already shown drastic capability of water dissociation at room temperature. In this direction we have heat treated TiO2 (TO) and synthesized BaTiO3 (BTO) in which oxygen defect induced strain through processing has been obtained. Oxygen vacancies produced in TO and BTO have been confirmed by Photoluminescence spectroscopy (PL). The cation-oxygen vacancy pairs (Ti+3-Vo) on the BTO surface provide acid-base pair to attract polar water molecules to get chemidissociated into OH− and H3O+ ions. Further chemisorbed surface hydroxyl ions provide high surface charge potential to physisorbed multilayer of water molecules dissociation and some of H3O+ ions get trapped inside the nanopores. The trapped ions inside nanopores generate enough charge potential to further physi-dissociate adsorbed water molecules. Titanium dioxide samples exhibit increase in strain that has been estimated from the X-ray diffraction results. Bond length and bond angle in both of TiO2 (TO) and BaTiO3 (BTO) decrease while strain increases in their lattice structure. A circular disc of 2 cm diameter and 1 mm thickness of TiO2 and BaTiO3 have been fabricated as hydroelectric cell. BTO based HEC of area 3.14 cm2 generated maximum current 3.66 mA and voltage 0.975 V. Varying the synthesis parameters to produce more defects in the compound may further increase electricity generation. Perovskite based HEC is very stable, repetitive and eco-friendly technique for portable green electricity generation.

A simple method for synthesizing VO2 with almost coincident hysteresis loops on Si substrate containing TiO2 buffer layer

The overlapped degree of hysteresis loops is critically important for the accurate response of vanadium dioxide (VO2)-based optoelectronics devices. Generally, the hysteresis loops width is not less than 10 ℃ for VO2 thin films deposited on amorphous SiO2/Si or Si substrates. In this work, the almost coincident hysteresis loops of VO2 thin films including a TiO2 buffer layer was synthesized successfully on Si substrate by a simple and controllable method. Here, the thickness of VO2 and TiO2 were 60 nm and 100 nm, respectively. XRD patterns show that the peak of rutile phase TiO2 begin to appear while the thickness of buffer layer increases to about 65 nm, which is more compatible with the lattice structure of VO2. Combined with the XPS spectra, it is found that the VO2 thin films formed on different substrates include quite a few V5+ and relatively few V3+ impurity phases. In addition, theoretical analysis indicates that an inversely proportional relationship exists between the hysteresis loops width and the average grain size of VO2 thin film, The SEM images confirm this point well revealing the average grain size of VO2 thin film does increase with the thickness increase of TiO2 buffer layer.

Nanoscale TiO2 and Ta2O5 as efficient antireflection coatings on commercial monocrystalline silicon solar cell

In this paper, we report the enhancement of photon to electron conversion efficiency of commercial monocrystalline silicon solar cells after deposition of nanoscale TiO2 and Ta2O5 as an antireflection coating. The nanoscale TiO2 and Ta2O5 ARC’s remarkably enhanced PEC efficiency of m-Si solar cells from 17.18% to 17.87% and 18.8% respectably. The enhancement in PEC efficiency is predominantly attributed to the increase in fill factor from 36.8% to 36.9% and 37.2% after deposition of nanoscale TiO2 and Ta2O5 as ARCs respectively. The reflectance of nanoscale TiO2 ARCs increased from 27% to 43% within the wavelength range from to 530 nm and decreases to 34% with increasing wavelength. However, for Ta2O5 the reflectance was 11% at 370 nm and increased up to 29% in the studied wavelength range. The reduced magnitude of reflectance for Ta2O5 throughout the studied wavelength resulted in notable improvement of PEC efficiency compared to TiO2. The phase formation of nanoscale TiO2 characterized by x-ray diffraction reviles the presence of both anatase and rutile phase TiO2 whereas Ta2O5 displays amorphous nature. The oxidation state of titanium (Ti) and tantalum (Ta) was evaluated from x-ray photon emission spectroscopy and observed to be in the form of Ti4+ and Ta5+ chemical state. The nanoscale thickness of both TiO2 and Ta2O5 ARCs was acquired by variable angle spectroscopic ellipsometry and found to be 55.2 nm and 70.8 nm respectively, and the same was confirmed by measuring cross-section thickness of ARCs using a scanning electron microscope.

The Effect of Electrophoretic Deposition Parameters on the Microstructure and Adhesion of Zein Coatings to Titanium Substrates.

Zein coatings were obtained by electrophoretic deposition (EPD) on commercially pure titanium substrates in an as-received state and after various chemical treatments. The properties of the zein solution, zeta potential and conductivity, at varying pH values were investigated. It was found that the zein content and the ratio of water to ethanol of the solution used for EPD, as well as the process voltage value and time, significantly influence the morphology of coatings. The deposits obtained from the solution containing 150 g/L and 200 g/L of zein and 10 vol % of water and 90 vol % of ethanol, about 4–5 μm thick, were dense and homogeneous. The effect of chemical treatment of the Ti substrate surface prior to EPD on coating adhesion to the substrate was determined. The coatings showed the highest adhesion to the as-received and anodized substrates due to the presence of a thick TiO2 layer on their surfaces and the presence of specific surface features. Coated titanium substrates showed slightly lower electrochemical corrosion resistance than the uncoated one in Ringer’s solution. The coatings showed a well-developed surface topography compared to the as-received substrate, and they demonstrated hydrophilic nature. The present results provide new insights for the further development of zein-based composite coatings for biomedical engineering applications.

Photocorrosion of CdS nanorod arrays and fabrication of CdS@TiO2 core@shell nanorod arrays by atomic layer deposition for improved photostability

In this manuscript, an interesting phenomenon was found that partially or entirely hollow CdS nanotube arrays (PEH CdS NT) were obtained after photocorrosion of CdS nanorod arrays (NR). The forming process of PEH CdS NT was studied in detail. Afterwards, CdS@TiO2 core@shell NR with controllable TiO2 thickness onto CdS NR were preparated by atomic layer deposition (ALD), and the photostability of CdS@TiO2 core@shell NR was studied. Compared with unmodified CdS NR, the CdS@TiO2-1500 core@shell NR (the thickness of the TiO2 layer was 1500 ALD cycles) exhibited higher photostability within 300 s, which could be ascribed to the TiO2 nanolayer. TiO2 nanolayer can protect CdS NR from photocorrosion because it can effectually transfer the hole and the electron separation from photoluminescence (PL) characteristic. These results suggest that CdS@TiO2 core@shell NR fabricated by ALD are effective in protecting of CdS NR from photocorrosion.

Effect of Insertion of Dielectric Layer on the Performance of Hafnia Ferroelectric Devices

Hafnia-based ferroelectric (FE) devices have attracted significant attention as nonvolatile memory devices due to their compatibility with complementary metal–oxide–semiconductor processes. Among them, the FE tunnel junction (FTJ) has been considered as the next-generation of nonvolatile memory devices owing to its neuromorphic characteristics and nondestructive read operation as well as the high-density integration. However, degradation of ferroelectricity in a thin hafnia film causes a reduced tunneling electroresistance (TER) ratio. In this work, we inserted a TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer into the metal–FE–metal capacitor to provide an asymmetric structure for FTJ operations and recorded the enhanced remnant polarization with enhanced ferroelectricity. In this study, a high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2{P}_{r}$ </tex-math></inline-formula> value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$44.4~\mu \text{C}$ </tex-math></inline-formula> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a notable TER ratio of 11.6 were observed for 6-nm thick hafnia films with 1-nm thick TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> films.

Pengukuran Daya Keluaran DSSC Terhadap Ketebalan Titanium Dioksida Berbasis Internet of Things

Topography and geographical conditions in Indonesia are very supportive in the effort to use solar energy as a producer of electrical energy. In this research, Dye Sensitized Solar Cell (DSSC) was fabricated using the doctor blading deposition method for coating TiO2 onto the substrate. The research focused on the effect of varying TiO2 thickness. TiO2 as an electron jumping pathway and binders for dye molecules, dye to absorb photons which will help generate electricity. the iodide / triiodide redox pair as electrolyte, and carbon as the counter electrode on the DSSC. TiO2, organic dyes, electrolytes, and counter electrodes are arranged and combined with a layered structure as a donor-acceptor layer. In testing the output power measurement using the Internet of Things, where testing cells at a thickness of 292 micrometers using a 7 watt LED lamp produces the maximum power reaches 4429.8 x 10-9 W.

A 2D Model for Interfacial Recombination in Mesoscopic Perovskite Solar Cells with Printed Back Contact

A physical model to explain the 2D charge recombination in mesoscopic graphite‐based perovskite solar cells (PSCs) having a highly selective front electrode and a nonselective back electrode is presented. Steady‐state photovoltage and photoluminescence (PL) as well as transient PL are studied for a wide range of device configurations, providing insights in the interface recombination at the front and back contact, namely, the mesoporous titania (m‐TiO2) and the graphite layer. Combining experimental evidence with the first 2D simulation of a perovskite solar cell, it is found that the characteristic thick absorber layer of mesoscopic graphite‐based PSC is a necessity to enhance the photovoltage. This is because the interface recombination at the back contact is a diffusion‐limited process. The electrode spacing should, however, not be enhanced by increasing the perovskite/m‐TiO2 thickness as this increases surface recombination losses at this interface. The study determines design rules for the optimal geometry of the mesoporous layers and helps to identify the limiting recombination pathways for an improvement of future device architectures.

Design and Synthesis of Novel NIR Dyes with Phosphonic Acid Derivative Anchoring Groups Aiming Towards Stable Dye-Sensitized Solar Cells

Introduction: The solar energy is a promising solution to the sustainable energy supply and the relevant environmental concerns. Production of the traditional solar cells is expensive and this poses difficulty for the mass-level implementation of this kind of solar cells. So, there has been a lot of effort and interest to propose cost-effective and efficient solar cells, where dye-sensitized solar cells (DSSCs) are one of the potential candidates. DSSCs have emerged due to their good photo conversion efficiency (PCE) beyond 12 % in spite of photon harvesting window mainly in the visible region (400-700 nm). Dyes are the “Heart” of the solar cells and anchoring group present in it not only controls the overall PCE but also stability of photo anode, which ultimately controls the stability of DSSCs. Amongst various anchoring groups, phosphonic acid has been widely reported to give improved stability to the DSSCs as compared to their most commonly used carboxylic acid anchoring group counterparts. Owing to huge possibilities of molecular structures, quantum chemical (QC) calculations have emerged as one of the potential tools for the prediction of their energetics and spectral behavior. The goal of this research is to propose and develop of novel near infrared (NIR) dyes bearing phosphonic acid groups having the capability of improved stability as well as PCE focusing on Donor-Acceptor-Donor framework bearing squaraine dyes. Experimental: In this work, a series of unsymmetrical squaraine (SQ) dyes such as SQ-143, SQ-148, SQ-151, SQ-157, SQ-159 bearing different phosphonic acid anchoring groups with the molecular structure as shown in the Fig. 1 were logically designed and subjected to QC calculations using 6-311G/DFT/B3PW91 and PCM model using ethanol solvent to judge their suitability as sensitizer before the synthesis. Some of the suitable dyes having favorable energetics have been synthesized by multistep synthetic route. Structural characterization and confirmation have been done by 1H NMR and Fab Mass techniques followed by their Photophysical characterizations in 5 µM ethanolic solution for electronic absorption spectral behavior. Adsorption behavior of these dyes on the mesoporous TiO2 has been investigated by adsorbing the respective dyes from their 0.1 mM solution in ethanol. Photovoltaic characterization was also performed after fabricating DSSCs based on 10-12 µm thick mesoporous TiO2 with adsorbed dyes from their 0.2 mM solution as photo anode, catalytic amount of Pt coated conductive glass as counter electrode and I-/I3 - as redox electrolyte. Results and Discussion: After the successful synthesis and structural characterizations, SQ dyes under investigation were subjected to their photophysical characterizations. It can be clearly seen from the solution as well as solid-state absorption spectra shown in the Fig. 1 that due to extended p-conjugation in SQ-148 and SQ-157, exhibit bathochromically shifted absorption maxima as compared to their SQ-143 and SQ-151 dye counterparts. At the same time, in spite of having two free –OH groups in the dyes SQ-148 and SQ-143, former exhibited less extent of the dye aggregation. A swift dye adsorption in combination with reduced aggregated species are highly desired for commercial applications. Investigation pertaining to the dye adsorption behavior on the TiO2 reveals the trend of SQ-143>SQ-148>SQ-157>SQ-151 suggesting that less aggregation tends to the relatively higher rate of dye adsorption. This can be attributed to the swift diffusion of the dye molecules in the nanopores of the mesoporous TiO2 during the dye adsorption process. Stability of the adsorbed dyes on the mesoporous TiO2 is another important parameter responsible to impart the stability to the DSSCs. This was conducted by investigating the dye binding strength based on dye desorption studies. Apart from their synthesis and photophysical characterizations, dyes were also used as sensitizer to fabricate the DSSCs and implication of the nature anchoring groups on photon harvesting and overall PCE was also investigated. Results on the photovoltaic performance revealed that newly designed dye SQ-159 makes a good compromise imparting improved stability as well as PCE amongst the dyes under investigation. Acknowledgement: SSP would like to express sincere thanks to the Japan Society for Promotion of Science for the financial support by Grant-in-Aid for scientific research (C) [Grant No.-18K05300] to carry out the research Figure 1

Controlling the Nucleation Morphology of Lithium Using ALD-Grown TiO2

Lithium (Li) metal batteries are desirable as rechargeable storage devices due to their high energy density; however, their practical implementation is hindered by the difficulty in controlling the Li metal plating microstructure. Artificial solid-electrolyte interphases (SEIs) have shown the potential to curtail the electrochemical instabilities of lithium, and atomic layer deposition (ALD) is commonly employed for the synthesis of thin-film artificial SEIs such as Al2O3 and alucone. However, these films quickly become delaminated as a result of their innate resistance to the cyclic shuttling of Li ions, resulting in marginal improvements in cell performance.Herein, we detail the use of ALD-grown TiO2 as a nucleation layer, rather than as an artificial SEI. We show that by depositing TiO2 directly on the Cu current collector, we can control the deposition morphology of Li in the widely studied ether-based electrolyte - 1M LiTFSi in an equal volume mixture of 1,3 dioxolane and 1,2 dimethoxyethane, with 1 weight percent of lithium nitrate as an additive. By optimizing the thickness of TiO2, we reveal that lithium nucleates into large deposits atop the TiO2 film under significantly reduced overpotential, resulting in a reduction in contact surface area with the electrolyte and an increase in cell performance. We report substantial improvements in cycling efficiency with an average Coulombic efficiency of 96% after 150 cycles at a current density of 1 mA cm-2 in Li/Cu cells. In comparison to the pristine cells, voltage profiles for the champion TiO2-modified cell display negligible loss in charge capacity in the mid and late-stage electrochemical cycles, indicating an improvement in the reversibility of lithium stripping and plating. Using X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS), we establish that lithium plates atop TiO2, rather than beneath it, suggesting that the presence of TiO2 supports the enhanced reversibility of Li stripping and plating. Also, we utilize coulometry and transmission electron microscopy (TEM) measurements to establish the effects of the TiO2 film. All performance and characterization data will be presented and discussed.

The Effect of Particle Size and Thickness on Nanocrystalline TiO2 Films on Dye-Sensitized Solar Cells for Indoor Application

Dye-sensitized solar cell has a unique property such as transparent, colorful characteristics and good performance under low/diffused light intensities, compared to other type of solar cells. Here, we have investigated effects of TiO2 particle size(14, 22, 50nm) and the thickness(2 to 20 μm) on nanocrystalline TiO2 films on photovoltaic performance in dye-sensitized solar cell under 1 sun, compact fluorescent lamp (CFL) and light-emitting diode (LED 3200K, 5000K) at 200 to 1000 lux. Further, the DSSCs fabricated using a TiO2 (22nm) film of 13.73 μm thickness at 1sun condition exhibited the best photovoltaic performance with highest power conversion efficiency (7.22%). However, the DSSC efficiency essentially follows the same trend with TiO2 film thickness, exhibiting the maximum efficiency value of 13.26 % for the 16.72 μm thickness of TiO2 (50nm) film at LED 3200K (1000 lux).

(Invited) C-14 Powered Dye-Sensitized Betavoltaic Cells: Next Generation Battery

A dye sensitized betavoltaic cell has been developed for the first time, which utilizes radioisotopic carbon, composed of nano-sized quantum dots, and ruthenium-based dye sensitized TiO2 as electrodes. The dye-sensitized betavoltaic cell (DSBC) is an energy generating device with a MLCT-based ruthenium ligand complex dye and a C-14 as a beta radiation source and a counter electrode. This combination allows for relatively efficient electron harvesting for improved performance in a betavoltaic device. The DSBC system using the Ru-N719 dye had an energy efficiency of 0.48%. If some problems are improved, DSBC can be used as a semi-permanent battery.We opened the new horizon that is explored first time in the field of betavoltaic. We believe it has potential to show higher efficiency through modifications such as optimization of TiO2 thickness, dye loading and energy control of beta radiation. The use of dye-sensitized semiconductor anodes in modified betavoltaic cells will create new opportunities in the field of nuclear batteries. The figure below shows an illustrated mechanism for dye-sensitized betavoltaic cell. Figure 1

Numerical simulation and proof of concept for performance assessment of cesium based lead-free wide-bandgap halide solar cells

Abstract Perovskite solar cells (PSCs) which utilize hybrid lead halide perovskite (CH3NH3PbI3) as a light absorber layer and exhibit some unique optoelectronic properties so have been emerging as fast-growing photovoltaic technology. However, lead halide-based perovskite has some challenges like stability and toxicity, which create an opportunity to investigate new materials. Lead-free halide perovskite remains a top contender for a possible replacement for these lead halide perovskites. Accordingly, this work mainly focusses on cesium (Cs) based lead-free halide perovskite solar cells which contain two different lead-free halides namely Cs2AgBi0·75Sb0·25Br6 wide bandgap halide 1 (WBH1) and Cs2AgBiBr6 wide bandgap halide 2 (WBH2). The bandgap of WBH1 and WBH2 is 1.82eV and 2.01eV, respectively. Detailed investigation of WBH1 and WBH2 based perovskite solar cells have been carried out to explore the efficiency potential of these devices. As a part of the complete research effort, device performance is optimized in terms of absorber layer thickness variation and by using different electron transport layer (ETL) and hole transport layer (HTL). During absorber layer thickness optimization, Spiro-OMeTAD and TiO2 are used as HTL and ETL respectively for both WBH1 and WBH2 based PSCs. Both WBH1 and WBH2 based solar cell with 300 nm absorber layer thickness reflected peak PV performance. WBH1 and WBH2 based solar cells reflected 12.39% and 8.43% conversion efficiency with TiO2 (ETL)/Cu2O (HTL) and MZO (ETL)/Cu2O (HTL), respectively. Results are analyzed using the energy band diagram, the current density-voltage (J-V) curve and external quantum efficiency (EQE). Studies carried out over here in this work may open up the window for the development of non-toxic, lead-free perovskite-based solar cell and help in exploring this field even more deeply.

Corrosion of Al2O3/Cr and Ti2O3/Cr composites in flowing air and CO2 at 750°C

Hot-pressed Al2O3/Cr and Ti2O3/Cr composites were exposed to synthetic air or CO2 at 750 °C. The Al2O3/Cr composites formed external Cr2O3 scales, and exhibited slow parabolic oxidation kinetics, in both gases. The Cr2O3 scales formed in CO2 possessed finer grains, and thickened at a faster rate, than Cr2O3 scales formed in air. The Ti2O3/Cr composites formed thick external TiO2 scales with internal oxidation zones that also contained Cr2O3 scales on subsurface Cr grains. After 20 h at 750 °C, the Ti2O3/Cr composites exhibited parabolic oxidation kinetics in both gases, although the oxidation rates were significantly higher than for the Al2O3/Cr composites.