Search

In this work, we describe the formation of a reduced bandgap CeNiO3 phase, which, to our knowledge, has not been previously reported, and we show how it is utilized as an absorber layer in a photovoltaic cell. The CeNiO3 phase is prepared by a combinatorial materials science approach, where a library containing a continuous compositional spread of CexNi1–xOy is formed by pulsed laser deposition (PLD); a method that has not been used in the past to form Ce–Ni–O materials. The library displays a reduced bandgap throughout, calculated to be 1.48–1.77 eV, compared to the starting materials, CeO2 and NiO, which each have a bandgap of ∼3.3 eV. The materials library is further analyzed by X-ray diffraction to determine a new crystalline phase. By searching and comparing to the Materials Project database, the reduced bandgap CeNiO3 phase is realized. The CeNiO3 reduced bandgap phase is implemented as the absorber layer in a solar cell and photovoltages up to 550 mV are achieved. The solar cells are also measured ...

Objective: To evaluate the feasibility and effectiveness of a wearable robotic device in guiding isometric torque generation and passive-active movement training for ankle motor recovery in children with acute brain injury. Participants/setting: Ten inpatient children with acute brain injury being treated in a rehabilitation hospital. Design: Daily robot-guided ankle passive-active movement therapy for 15 sessions, including isometric torque generation under real-time feedback, stretch-ing, and active movement training with motivating games using a wearable ankle rehabilitation robot. Main measures: Ankle biomechanical improvements induced by each training session including ankle range of motion (ROM), muscle strength, and clinical (Fugl-Meyer Lower-Extremity (FMLE), Pediatric Balance Scale (PBS)) and biomechanical (ankle ROM and muscle strength) outcomes over 15 training sessions. Results: As training progressed, improvements in biomechanical performance measures followed logarithmic curves. Each training session increased median dorsiflexion active range of motion (AROM) 2.73° (standard deviation (SD) 1.14), dorsiflexion strength 0.87 Nm (SD 0.90), and plantarflexion strength 0.60 Nm (SD 1.19). After 15 training sessions the median FMLE score had increased from 14.0 (SD 10.11) to 23.0 (SD 11.4), PBS had increased from 33.0 (SD 19.99) to 50.0 (SD 23.13) (p

We investigate the significance of indium (In) doping of Co3O4 in the operation of TiO2|Co–In–O|RuO2 all-oxide solar cells by employing combinatorial experiments and density functional theory (DFT) calculations. We observed an increase in the open-circuit voltage, Voc, of more than 240 mV with an enhancement by a factor of 4 in the short-circuit current, Jsc, in the low-doping range. This constitutes a maximum power that is five times greater than that of pure Co3O4-based photovoltaic (PV) devices. Surprisingly, a concurrent marginal change in the band gap and a decrease in the optical absorption coefficient as a function of indium concentration was observed, contrary to what has been assumed previously. Using DFT in conjunction with joint density of states calculations, we show that with increasing amounts of In, there is a reduction in the low-energy photon absorption due to disallowed electronic transitions. Moreover, we show that emergence of In 5s states results in a free-electron-like band in the co...

Recently, metal oxides have been gaining large interest in the field of renewable energy. This fact is mostly related to their properties which make them suitable for long lasting, cost efficient and environmentally friendly devices. Dimanganese trioxide (Mn2O3) was investigated in the past in different fields, yet, the fabrication of the film in most cases is not straightforward and requires several steps, consequently there is insufficient data provided in literature regarding this material. This paper presents a single step deposition of dimanganese trioxide (Mn2O3) thin films by spray pyrolysis on glass substrates at temperatures lower than 450 °C. The process was conducted under atmospheric conditions, making it an ideal and cost effective fabrication technique for large scale manufacture. The obtained Mn2O3 film was characterized chemically and physically. The film X-ray diffraction analysis reveals a crystalline phase of α-Mn2O3 in a bixbyite-like structure. Physical characterization included optical absorptance, band gap analysis, energy band diagram, and four-point probe resistivity measurement. The film exhibits a band gap of 1.4 eV making it a good candidate for applications such as solar cells.

Here we investigate the impact of four different metal back contacts on the photovoltaic (PV) performance of Co3O4 thin film all-oxide photovoltaic cells. A combinatorial TiO2|Co3O4 heterojunction thin film device library was made with thickness gradients for both metal oxide layers. Grids of four different metal back contacts were then deposited on top of these layers. A significant effect of the metal back contacts on the final photoconversion performance has been observed by combinatorial PV measurements. We analyze these results via advanced numerical simulations and different scenarios in order to explain the recombination mechanisms at the different back contacts. We conclude that the nature of the back contact material controls the density of surface states and, therefore, the undesirable surface recombination at the absorber–back contact interface. This project has received funding from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement No 309018. Funding from the European Union Seventh Framework Program [FP7/2007-2013] under grant agreement 316494 is also acknowledged.

In this work, we describe the formation of a reduced bandgap CeNiO

Oxide materials have been widely investigated for use as absorber layers in high-performance solar cells, and in this study combinatorial methods were used to specifically investigate cobalt–iron (Co–Fe) oxide composites. Structural inversion of Co–Fe oxides from a normal to an inverse spinel structure occurs at the critical composition of approximately 33 % Fe added to Co, causing changes in the crystallinity, symmetry, sub-lattice vibrational modes, optical bandgap, and electrical resistivity. When used as an absorber layer in all-oxide solar cells with the multi-layered geometry of glass|FTO|TiO2|Co–Fe–O|Au, enhanced photovoltaic performance was observed, with a maximum Voc of 534 mV at a composition of approximately 45 % Fe and a 200 % improvement in Pmax compared to cobalt-rich devices. Using combinatorial data maps of the various material properties, a significant correlation between the solar cell properties and the chemical composition of the Co–Fe–O layer was revealed. This correlation allows for a better understanding of the Co–Fe–O system, which is a necessary step towards the development of Co–Fe–O-based all-oxide solar cells.

The high open-circuit potential (Voc) achieved by perovskite solar cells (PSCs) is one of the keys to their success. The Voc analysis is essential to understand their working mechanisms. A large number of CH3NH3PbI3-xClx PSCs were fabricated on single large-area substrates and their Voc dependencies on illumination intensity, I0, were measured showing three distinctive regions. Similar results obtained in Al2O3 based PSCs relate the effect to the compact TiO2 rather than the mesoporous oxide. We propose that two working mechanisms control the Voc in PSCs. The rise of Voc at low I0 is determined by the employed semiconductor n-type contact (TiO2 or MgO coated TiO2). In contrast, at I0 close to AM1.5G, the employed oxide does not affect the achieved voltage. Thus, a change of regime from an oxide-dominated EFn (as in the dye sensitized solar cells) to an EFn, directly determined by the CH3NH3PbI3-xClx absorber is suggested.

Growth in energy demands, coupled with the need for clean energy, are likely to make solar cells an important part of future energy resources. In particular, cells entirely made of metal oxides (MOs) have the potential to provide clean and affordable energy if their power conversion efficiencies are improved. Such improvements require the development of new MOs which could benefit from combining combinatorial material sciences for producing solar cells libraries with data mining tools to direct synthesis efforts. In this work we developed a data mining workflow and applied it to the analysis of two recently reported solar cell libraries based on Titanium and Copper oxides. Our results demonstrate that QSAR models with good prediction statistics for multiple solar cells properties could be developed and that these models highlight important factors affecting these properties in accord with experimental findings. The resulting models are therefore suitable for designing better solar cells.

Data mining tools have been known to be useful for analyzing large material data sets generated by high-throughput methods. Typically, the descriptors used for the analysis are structural descriptors, which can be difficult to obtain and to tune according to the results of the analysis. In this Research Article, we show the use of deposition process parameters as descriptors for analysis of a photovoltaics data set. To create a data set, solar cell libraries were fabricated using iron oxide as the absorber layer deposited using different deposition parameters, and the photovoltaic performance was measured. The data was then used to build models using genetic programing and stepwise regression. These models showed which deposition parameters should be used to get photovoltaic cells with higher performance. The iron oxide library fabricated based on the model predictions showed a higher performance than any of the previous libraries, which demonstrates that deposition process parameters can be used to model photovoltaic performance and lead to higher performing cells. This is a promising technique toward using data mining tools for discovery and fabrication of high performance photovoltaic materials.

Background Recent advancement in the technology of virtual reality (VR) has allowed improved applications for cognitive rehabilitation. Objectives The aim of this review is to facilitate comparisons of therapeutic efficacy of different VR interventions. Methods A systematic approach for the review of VR cognitive rehabilitation outcome research addressed the nature of each sample, treatment apparatus, experimental treatment protocol, control treatment protocol, statistical analysis and results. Using this approach, studies that provide valid evidence of efficacy of VR applications are summarized. Applications that have not yet undergone controlled outcome study but which have promise are introduced. Results Seventeen studies conducted over the past eight years are reviewed. The few randomized controlled trials that have been completed show that some applications are effective in treating cognitive deficits in people with neurological diagnoses although further study is needed. Conclusion Innovations requiring further study include the use of enriched virtual environments that provide haptic sensory input in addition to visual and auditory inputs and the use of commercially available gaming systems to provide tele-rehabilitation services. Recommendations are offered to improve efficacy of rehabilitation, to improve scientific rigor of rehabilitation research and to broaden access to the evidence-based treatments that this research has identified.