Multijunction solar cell spectral response determination at radiation damage study

This paper discusses multijunction solar cells with optically coupled p-n junctions under radiation exposure photosensitivity spectral response study. It is shown that if the measurement technique does not consider the luminescent coupling and does not track the optical coupling degradation, then instead of a decrease (which is a natural response of a photoconverter to radiation damage), an abnormal increase in the narrow-bandgap photoresponse (receiving luminescent radiation) subcell due to radiation damage can be observed. Accordingly, with an increase in the irradiation dose, an increase in the subcell photocurrent forming a “negative” degradation dependence of MJ SC being used in space applications is recorded.

Effect of spectral composition of light on the production characteristics of Arthrospira (Spirulina) platensis

The study of the growth of the batch culture of Spirulina platensis with different spectral composition of LED and luminescent radiation in plane-parallel photobioreactors was carried out. In the experiments, we used LED lamps LCD Feron LB-213 10 W, as well as fluorescent lamps TDM Electric 18 W. It has been shown that the maximum productivity of A. platensis does not depend on the radiation spectrum and is 0,25 g·l-1·day-1 at an energy of 45 W·m-2. In the linear phase of growth, the efficiency of light energy conversion (efficiency of photobiosynthesis) was calculated, taking into account that the culture absorbs 90% of the incident light: the maximum value was obtained for LED and fluorescent lighting (23 W·m-2 and 17 W·m-2 respectively), which turned out to be the same and amounted to about 3,78 %. The minimum efficiency of 2,69% is obtained with fluorescent lighting at 34 W·m-2.

Photoluminescent Control Ripeness of the Seeds of Plants

The development of technology for objectively determining the ripeness of plant seeds is an urgent task of modern agricultural production. An alternative to existing methods is optical photoluminescent technology, which is characterized by high accuracy, selectivity, expressiveness, as well as being remote and non-destructive. The spectral characteristics of excitation and photoluminescence of wheat, oat, and corn seeds during their maturation were measured using a spectrofluorometer using a previously developed technique. It was found that during maturation, the short-wave component of the excitation spectra decreases (λs=362 nm) and the long-wave component increases (λl=485 nm). After measuring the luminescence spectra, the integral photoluminescence fluxes for long-wave and short-wave excitation, as well as their ratio, were determined. We have obtained statistically reliable linear regression models of the dependence of long-wave and short-wave photoluminescence flows on the maturation time. Based on the obtained dependencies, a technology was developed for determining the degree of physiological maturation and making decisions about harvesting ripe seeds. It includes sample preparation, excitation and registration of luminescent radiation, amplification of the received signals and their relations, obtaining information about the degree of ripeness taking into account a priori dependencies.

Change of silica luminescence due to fast hydrogen ion bombardment

This paper deals with the luminescence of silica (KV-type) induced by beam of hydrogen ions with the energy of 210 keV per nucleon. An average implantation dose of up to 3.5 × 1021cm−3(5 × 1010Gy) was accumulated during irradiation over an extended period. The luminescent spectra consisted of the blue band (maximum at 456 nm) and the red band (650 nm) in the visible range. It was shown that increase in the absorption dose had an effect on the silica luminescence. It was found that the most significant changes in the spectrum occurred during the dose accumulation in the region of 550–700 nm. The shape of the spectrum of the luminescent radiation in this wavelength range was affected both by the oxygen deficient centres (blue band) and non-bridging oxygen hole centers (red band). Mathematical processing of the experimental spectra permitted to identify contributions to the luminescent radiation coming from both types of defects.