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Diffustion length

Diffustion length. http://www.pveducation.org/pvcdrom/solar-cell-operation/collection-probability. the cell's spectral response (SR) is determined by dividing the short-circuit current at each wavelength by the light power incident on the cell. E ffect of temperature.

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Diffustion length

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  1. Diffustion length

  2. http://www.pveducation.org/pvcdrom/solar-cell-operation/collection-probabilityhttp://www.pveducation.org/pvcdrom/solar-cell-operation/collection-probability

  3. the cell's spectral response (SR) is determined by dividing the short-circuit current at each wavelength by the light power incident on the cell

  4. Effect of temperature

  5. Effect of temperature

  6. Effect of temperature

  7. Effect of temperature

  8. Experiment set up • The sensor of the camera is kept at 78K by a Stirlingcooler, which gives a noise level of k’20mK without any lock-in technique. The frames are collected by a frame grabber card (inside the computer). The subsequent two-channel lock-in calculation is performed by the computer, as well as various control functions. The computer is controlled by a self-developed software. • Feeding a temperature signal:

  9. Lock-in IR-Thermography - a novel tool for material and device characterization

  10. Comparison of a fast (2 s, left, ¼22 mK) and a high-quality (2 h, right, ¼0037 mK) LimoLITmeasurement of a 125*125 cm screen-printed industrial mc Si solar cell. Modulation frequency was 75 Hz. All major shunts are visible in the fast measurement

  11. Vomo-Limo comparison

  12. WAVELENGTH-DEPENDENT GENERATION AND THERMALIZATION

  13. Peltier effect Assuming Eg 1.1 eV, UD 720mV, and U 320mV, the maximum LimoLIT signal is double the Vimo signal. For the shunts marked in Figure 2 the signal strength in the LimoLIT measurement is increased by about 50%.

  14. Figure 3. Conventional VomoLIT measurement of the solar cell shown in Figure 2 in forward direction with a constant-bias voltage applied (left). LimoLIT measurement of the same cell with a constant-bias light, realized with an adjustable light source (right). Measurement time was 10 h as in Figure 2

  15. QUANTITATIVE LOCK-IN THERMOGRAPHY INVESTIGATIONS • Local I–V characteristics measured thermally (LIVT) • Quantitative measurement of shunt currents

  16. FIGURE 4 Lock-in thermogram (amplitude image, scaled to 2 mK) of a multicrystallineEFG(edge-defined film-fed growth) solar cell measured at 0.5V with different averaging areas indicated

  17. Thermally measured I–V characteristic of the local shunt Measured dark I–V Characteristic of the complete cell and simulated cells without edge shunts and without any shunts

  18. What ARE TLCS? • thermochromic liquid crystals (TLCs). Fundamentally, a liquid crystal is a thermodynamic phase that is between the pure solid and pure liquid phases. • When a TLC is at its event temperature, illuminated by white light1 and viewed under fixed optical conditions, the TLC material will reflect a unique wavelength2 of visible light (i.e.,color). As the temperature rises through the TLC’s bandwidth, the reflected color of the TLC will change. Finally, when the temperature exceeds the TLC’s clearing point temperature, the material will enter the pure liquid state and will revert back to being transparent. This phenomenon is selective reflection and occurs in most TLCs both on heating and cooling and occurs with minimal hysteresis.

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