Contribution of the solar effect in LEDs and spectral responses

. This experimental work describes our work on spectrometric measurements (spectral responses) and measurement of sensitivity of solar radiation by (simulating the solar to a powered lamp) on commercial light emitting diodes of different colors (LEDs). The first experiment was carried out at the electronics department in University of USTHB Bab Ezzouar (Laboratory of thin layers) which has a measurement bench allowing the relative spectral representation of the photo of the detector noted Vphot (λ).


Conventional low power LEDs are a very interesting alternative to traditional sources such as fluorescent, incandescent or discharge lamps
They offer many advantages; low power consumption, a very long lifespan and the possibility of selecting a precise color among many others. .The application that made LEDs known to the general public, Indeed, white LEDs are driving this market, Thanks to the development of blue LEDs Several studies in terms of scientific research have proven the potential of LEDs as an efficient light source for the development and growth of plants in controlled environments [1,2].Among the essential advantages of LEDs are the possibility of recomposing the ideal spectrum and the adjustment of light intensity necessary for photosynthesis at the plant level, in addition to their energy efficiency.
Moreover, the emission of a LED is not purely monochromatic [3], its width depends on the energy of gap as well as on the temperature.LED performance doubles every 3 years, with prices divided by 10 every 10 years [4].
Light emitting diodes are very small sources that emit a large flux at a reduced solid angle [5].

wavelengths specific to desired applications, eg plant responses., Heat in The residual LEDs are transmitted separately from the light-emitting surfaces through active heat sinks. The light source placed near the cultivation surfaces does not heat the plants there is no risk of stress, for high intensity LED
As for their solar effect, little work has been done in this direction.
In the near future (2022), LEDs are expected to be the most efficient and reliable light sources in the market.These LEDs open up an exceptional field of potential innovations.According to J. Nelson of Sandia Laboratories: "If all the incandescent lamps in the world were replaced by LEDs, we could save about 38 nuclear power plants."This perspective demonstrates the importance of research in this area.

Little work has been done on the effect of solar radiation.
u:arbitrary unit represents the relative ratio of light intensity

2-Measurement of the sensitivity of the different LEDs green, yellow.
We used the assembly shown in figure 2 .We attach an LED on a rod and we light up with a lamp placed at a hundred centimetres away The LED is excited by the The LEDs have many advantages for plant growth both in terms of energy efficiency and photo synthetics.In addition, with their long lifespan, they are able to ensure economic profitability for producers.

In this work, two measuring devices were installed to measure the spectral responses of three different light emitting diodes (LEDs) in emission and absorption
In addition, another experiment using a measurement bench to simulate sunlight with a spectral lamp.

Measurements of the sensitivity of various LEDs as a function of the power illumination of a light source show that the illumination is almost
proportional to the voltage across these.LEDs and that for the same voltage of the LED the lighting is different and that the green LED is the most sensitive, then the yellow, the less sensitive is the red.

This shows that the lamp light has an effect on these LEDs
The measurements were carried out on these LEDs and we determined the emission and absorption wavelengths as well as the maximum intensity Imax and the voltage Vsmax of each LED.This work allowed us to draw up a comparative assessment.The results obtained from the different emission and absorption spectra are considered quite interesting.
We also noticed that the graph of the illumination E (lux) = f (VLED) gives a response of the LED for each illumination of the lamp and we observe a difference in sensitivity, the green LED with an illumination of 135lux, then the yellow 80 lux and finally the red 50 lux.These results agree with the results of the measurements made on the part (radiometric measurements with pyranometer).This result validates our work on the effect of the light of the lamp or the photovoltaic effect of the sun.
The results obtained will of course validate our hypotheses, which has already been established, I willl also make it possible to assess the potential of LEDs in the photovoltaic field.