In this work are presented the results obtained with solar cells sensitized with quantum dots of cadmium sulphide (CdS) incorporating luminescent materials (NaYF4:Yb/Er). The study revealed that through using a bifunctional layer of NaYF4:Yb/Er submicron rods, the infrared radiation is absorbed in 980nm to generate luminescence in the visible region to 530nm, under the UP-conversion process, in the same way simultaneously, NaYF4:Yb/Er layer causes scattering toward the quantum dots, the emission and scattering generated by this material is reabsorbed by the QD-CdS, and these in turn are absorbing in its range of solar radiation absorption, Thus generates an increase in the electron injection into the semiconductor of TiO2. The results of a cell incorporating NaYF4: Yb/Er at 0.07M shown photoconversion efficiencies of 3.39% improving efficiency with respect to the reference solar cell without using NaYF4: Yb/Er of 1.99%. The obtained values of current and voltage showed a strong dependence of the percentage of NaYF4 Yb/Er, and the mechanism of incorporation of this material.
Solar energy systems use concentrating optics with photovoltaic cells for optimizing the performance. Advanced
concentrators are designed to maximize both the light collection and the spatial uniformity of radiation. This is important
because irradiance uniformity is critical for all types of photovoltaic cells. This is difficult to achieve with traditional
concentrators, which are built with polished optical surfaces. In this work we propose a new concept of solar
concentrator which uses small diffuser segments in key points to increase the irradiation uniformity. We experimentally
demonstrate this new concept by analyzing the effects on both efficiency and irradiance uniformity due to the
incorporation of scattering ribbons in a compound parabolic concentrator.
There is an enormous range of possible color distributions that may be created with a light cone when the primary source
is an array of multicolor light-emitting diodes (LEDs). If one looks through a lightpipe toward an LED array, multiple
images of the color LEDs can be observed as in a kaleidoscope. A tapered lightpipe behaves as a three-dimensional
kaleidoscope, and then, by changing the position and orientation of the red-green-blue LEDs can produce a plenty of
amazing illumination patterns. We analytically calculate this color spatial distribution of the illumination pattern
produced by a tapered lightpipe. Moreover, we simulate these color illumination patterns, and analyze their structure and