Susceptibility to environmental factors, such as moisture, humidity, oxygen, heat, and ultraviolet (UV) light (photoinstability), has affected perovskite solar cell (PSC) stability in practical applications. To overcome the instability and performance degradation due to oxygen, humidity, and moisture, different strategies and encapsulation schemes have been proposed, and promising results have been obtained. However, photostability remains a major hurdle because UV light is an inherent part of the standard incident spectrum of PSCs. To prevent photoinstability and increase quantum energy harvesting levels, cadmium chalcogenide (CC) photoluminescent (PL) filters for downconverting the UV part of the incident spectra obtained for PSCs are proposed in this work. The concept was illustrated by matching 500-nm-thick CC-PL filters to the front glass of a PSC to form a CC-PL/glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)/perovskite/Ag structure. Cadmium sulfide (CdS), cadmium selenide, and cadmium telluride were taken as the CC materials. Practical measurements confirmed that the PSC with the CdS-PL filter can maintain 92% of its initial value under continuous light soaking for more than 100 h. Furthermore, this PSC exhibited the best improvement in power conversion efficiency.
A complaint mechanism to extend resolution in the Fourier Transform Spectroscopy (FTS) technique has been designed,
fabricated and tested. The mechanism based on the complaint mechanical design strategy has not mobile parts and was
fabricated in MEMS technology in a Bosch Process. When this mechanism is used to displacing the mobile mirror in a
FTS setup, an extended range travel for the reference mirror is achieved; thus, the optical path difference and hence the
resolving power of the FTS system is increased.
The fabricated device has dimensions of 5400x4200x400 Microns at the large, width and thickness respectively, with an
aspect ratio about 10. Numerical simulations with ANSYS Software were developed to get the Stress limits and the input
and output displacements, the mechanical gain and the resonance frequency of the device.
Experimental results in both the forced and dynamical regime are presented. It is found that in the dynamical regime
when the device is operated at its resonance frequency it exhibits a higher mechanical gain several times its gain in the
forced regime.
Dynamic noise elimination in 2-D periodic structures is achieved with a liquid crystal display used as a 2-D incoherent reconfigurable source. The method, which is based on the Lau effect, shows that under certain conditions it can be used for correcting, in real time, defects dues to noise in 2-D periodic structures. Experimental verification of the noise elimination is presented.
Intrinsic properties of liquid crystals spatial light modulators, as sampling devices are commonly seen as disadvantages in opto-digital data processing; because the loss of light power due the replicated spectrum at the sampling process. We claim this apparent disadvantage can be seen as an advantage if we consider to filter Q replicates of the Sampled image Fourier spectrum. Moreover, we can use this technique to improve the signal to noise ratio (S/N), or to develop several operations in parallel over the same input data. In this work we are interestd in improving the S/N in opto-digital image substraction. Experimental results which reveal the advantage of this technique are shown.
We describe a novel spatial filter that produces a low-pass modulation transfer function (MTF), evenwhen the filter uses a high pupil aperture. Furthermore, we show that the filter's MTF has low sensitivity to focus errors. Numerical simulations are reported.
We present a family of apodizers with random transmittance for achieving high focal depth, without sidelobes along the optical axis. Numerical simulations illustrate the properties of these apodizers.
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