Summary
To improve the light‐harvesting properties of dye‐sensitized solar cells (DSSCs), light from the ultraviolet (UV), visible, and infrared (IR) regions of the solar energy should be effectively harvested. Ru(II)‐based dyes play a key role in harvesting energy from parts of the UV and visible regions but cannot absorb IR light. A strategy for improving the DSSC efficiency is to employ upconversion phosphors (UCPs) that can convert IR into visible light. In this study, using TiO2:Er3+, Yb3+ UCPs fabricated via a simple aerosol process and calcination, we examine the effects of upconversion and light scattering of UCPs added into the TiO2 thin‐film‐based photoelectrode on DSSC efficiency. Under IR irradiation, the fabricated TiO2:Er3+, Yb3+ UCPs emit visible light with emission peaks at 529, 550, and 650 nm. The power conversion efficiency (PCE) of the DSSCs is significantly improved by adding the optimized amount of UCPs with the average size of 500 nm in the TiO2 nanoparticles (NPs) matrix with the average size of 25 nm due to light upconversion and scattering effects. However, the addition of excess UCPs deteriorates the DSSCs efficiency owing to the rapid recombination between photogenerated electrons and holes and the increased interfaces between UCPs and TiO2. These results suggest that the light‐harvesting efficiency of DSSCs in the IR region can be enhanced by employing the optimal amount of large‐sized UCPs as light upconversion and scattering medium in the TiO2 thin‐film‐based photoelectrode.
Purpose The aim of this study was to find effect of task oriented training including aftereffect after applying low frequency (1Hz) or higt frequency (10Hz) repetitive transcranial magnetic stimulation (rTMS) on hand spasticity in stroke patients. Methods Forty patients with history of stroke and upper limb hemiparesis (age at intervention: 51.3 years, time after stroke onset: 11.3 months) were studied. Forty patients were divided into four groups; task oriented training including aftereffect after applying high frequency (10Hz) rTMS (TIAH, n=10), task oriented training excluding aftereffect after applying high frequency (10Hz) rTMS (TEAH, n=10), task oriented training including aftereffect after applying low frequency (1Hz) rTMS (TIAL, n=10), task oriented training excluding aftereffect after applying low frequency (1Hz) rTMS (TEAL, n=10). The intervention was performed for four times a week, for four weeks. Results As shown by the result of the Modified Tardieu Scale (MTS), there were significant differences on follow up test in the hand spasticity of the TIAH group, wheras there was a significant difference on during intervention (between baseline and 4 weeks) in those of the TEAL group. Furthermore, results of motor evoked potentials (MEPs) showed significant differences in all four groups. Conclusion The 4 weeks protocol of TIAH seems effective in improving hand spasticity in upper limb hemiparesis after stroke.
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