22-11-2018 Experiment 9 to do list:
Tested solar cell with an area of approx. 0.5 cm2 it is mounted on the stage that can be heated in the range of 0 - 90ºC. The cell's lighting is a white diode LED, which power can be adjusted using a potentiometer. Maximum light power corresponds to approximately 1000 W / m2. The cell is in contact with the external circuit in the form of a computer controlled "black box", which produces the desired voltage in the range of -1 V to +1 V and at the same time measures the current flowing through the cell.
- Perform measurements of the current-voltage characteristics of the cell at maximum current supplying the LED diode at temperatures from 5 to 60ºC with a jump of 10ºC.
- Determine the parameters Voc, Isc, FF and η for all characteristics. Observe how they change as a function of temperature, perform their graphs and draw conclusions.
- For 25ºC, perform a series of characteristics for different light intensities, changing them so that the short-circuit current decreases by more or less factor 2 and measure the dark characteristics
- Calculate cell performance for different light intensities, assuming proportionality between Isc and the intensity of light. Draw conclusions about operation of the cell in low light conditions.
- Compare the dark characteristics with the clear ones and draw conclusions about "Rules of superposition" for the tested cell.
The measuring system containing the monochromator will be used to measure the distribution spectral quantum efficiency. We will use the previously determined distribution spectral spectrum of light emitted by the halogen lamp used in experience.
- Measure the photocurrent generated in the cell as a function of wavelength in the 4000-1200 nm. Adjust the wavelength values so that the measuring points are uniform and sufficiently dense (not less than 0.05 eV) distributed on an energy scale.
- Using the photon flux file containing the spectral distribution of incident light for a sample, make a graph of the photocurrent distribution as a function of the energy of incident photons normalized to one photon falling (because we do not know the exact number photons falling on the structure, we can only determine this distribution in units any)
- Determine the value of the absorber's energy break using the "in half the edge. "
- Determine the energy corresponding to the high-energy edge of the distribution. Why there’s a response?
- Compare the Voc (T) value for T-> 0 with the energy gap value received from extrapolation of Voc (T) to 0oK, draw conclusions.
19-11-2018 The last meeting will take place on Dec 3
12-11-2018 has been announced a bank holiday this year. We are awaiting for the statement from the WUT officials on the way we tackle the teaching on that day.
Final report structure
1. Introduction - brief introduction to the topic, decription of technology being investigated, description of physical and chemical processes, working principles.
2. Results - collected data presented in the plots (scattered plots), processing of the data, description of methodology and analysis, calculations.
3. Conclusions - calculated values, comparison with state of the art, discussion of the results