J. Plá

SAC-A satellite: first experiment of Argentine solar cells in space

On December 1998, the Endeavour space shuttle launched the Argentine satellite SAC-A. Among several technological experiments, this satellite included a set of crystalline silicon solar cells fabricated in Argentina to test them in the space environment. In this paper, we describe the experiments associated with these solar cells and analyze the corresponding telemetry data received from January to July 1999. Simultaneously, several radiation damage experiments using 10 MeV protons supplied by a cyclotron accelerator were performed. The variation of the electrical characteristics of the irradiated cells are also presented.

Impact of the titania nanostructure on charge transport and its application in hybrid solar cells

Porous titania films are widely studied in a number of optoelectronic applications due to its favorable optical and electronic characteristics. Mesoporous titania thin films (MTTFs) with tunable pore size, pore order, accessibility and crystallinity are of interest in electronic devices due to the potential for optimization of the desired characteristics for charge separation and carrier transport. In this work, several MTTFs were prepared by sol–gel chemistry with different structural properties tuned by post-synthesis thermal treatment. The effect of the structural properties (pore diameter, order and accessibility) on the electrical properties of the material was studied by films fabrication onto a transparent conducting electrode, ITO, such that it enables optoelectronic applications. The performance as photoanode was explored by the fabrication of hybrid polymer (P3HT): titania solar cells. Not only does structural properties affect polymer impregnation inside the titania pores as expected and hence impacts charge separation at the interface, but also the thermal treatment affects crystallinity and the films electronic properties. A more complete picture about the electronic properties of the different MTTFs prepared in this work was studied by mobility measurement by space charge limited current and impedance spectroscopy.

A new method for the determination of the minority carrier lifetime based on a biased OCVD technique [solar cells]

A new simple method for the determination of the solar cell minority carrier lifetime (/spl tau/), based on a biased OCVD technique, is analyzed. In this case, the excitation is given by a pulsed light source (time dependent contribution) plus a continuous illumination (continuous forward bias). Under appropriate conditions, this configuration produces an exponential decay with a time constant which depends on the bias. This constant decreases monotonously as a function of bias and allows one to determine an effective /spl tau/ for the base region. Inexpensive test equipment has been developed which basically consists of two sets of high-efficiency GaAs LEDs, which provide both light contributions. Measurements have been performed on crystalline silicon solar cells elaborated in the Argentine Atomic Energy Commission. Experimental results show good agreement with the theoretical model and with numerical PC-1D simulations.