Short Circuit Current Density

The is the photocurrent density generated by a PV device under illumination at short circuit condition. It is dependent on the intensity of incident and absorption spectrum of photoactive material (donor/acceptor) by the relation  

Once we obtain the erternal quantum efficiency of polymer solar cells, the value of Jsc can be calculated from the overlap between the absorption spectra of the materials and the sunlight AM 1.5 G spectrum. 

Type Material Thickness (nm) Material Thickness (nm) Area (cm ) Quoted Corrected (mA.cm ) Reference 

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PV current-voltage and power-voltage characteristics of a standard GaInP2/GaAs tandem cell were measured under 100 mW/cm2 illumination. The PV parameters under illumination were an open-circuit voltage Vroc = 2.32 V, a short-circuit current density Jsc = 13.4 mA/cm2, a fill factor FF = 0.88, and a PV conversion efficiency of 28.5%. Under the... 

The PV characteristics of the CIGS2 thin-film solar cell on opaque Mo back contact, as measured at the NREL under AM 1.5 conditions, were as follows short-circuit current density sc of 20.88 mA/cm2, open-circuit voltage 1% of 830.5 mV, fill factor FF of 69.13%, and PV conversion efficiency // of 11.99%. 

He, I. Zhong, C. Huang, X. Wong, W.-Y. Wu, H. Chen, L. Su, S. Cao, Y., Simultaneous enhancement of open-circuit voltage, short-circuit current density, and fill factor in polymer solar cells. Adv. Mater. 2011, 23, 4636-4643. 

Fig. 10 Simulated solar cell electrical behavior in the dark dotted traces) and under illumination (solid traces) comparing the effect of the saturation current parameter 7 on Foe- The black traces represent a device with /g x 10 that of the device represented by the red traces. The sharp inflection points in the semilog plots (upper panel) are the points where the current switches from positive to negative. Also illustrated in the linear representation (lower panel) are the short circuit current density, J c, and the maximum output power, Fmax. given by the product of current and voltage. The blue arrows represent the point at which the dark current and the current under illumination are equal in magnitude. The corresponding potential marked in blue on the voltage axis is Foe for the black trace...

Koyama has examined the sensitization behavior of a series of pheophorbide sensitizers (112-117) with similar structure. The results indicate that the short-circuit current density as well as the overall solar energy-to-electricity conversion efficiency increased with the increasing Qy absorption and with the decreasing one electron-oxidation potential. Two empirical models are built based on the experimental results. One model suggests a parallel electron injection from both excited and ground states to the conduction band of Ti02 whereas the other one supports an electron injection via the excited state only, in which both the Qy absorption and the Qy-state one electron-oxidation potential can contribute [110]. 

Fig. 8.2. J/V-curve with description of solar cell parameters efficiency /, fill factor FF, open circuit voltage Voc, and short circuit current density Jsc- The photogenerated current density Jph is indicated by the dotted line. More details of these and all other parameters are given in the text...

Table 8.1. Surface properties of the etched ZnO Al films shown in Fig. 8.8. Root mean square roughness (ArrrlK), haze at a wavelength of 700 nm, and resulting short circuit current density, when applied in 1.1pm thick pc-Si I1 solar cells...

Fig. 8.9. Measured quantum efficiency (QE) and cell absorption (1 — R) of pc-Si H solar cells on the RF sputtered ZnO Al front contacts shown in Fig. 8.8 smooth (dashed), after a short etching step (solid), and after optimized etch duration (dotted). Resulting short circuit current densities are 16.3, 19.8, and 23.4mAcm-2, respectively...

As already mentioned in Sects. 6.3.1.2 and 8.2.3, ZnO can be used as an intermediate reflector in a-Si H/ j,c-Si H tandem solar cells between top and bottom cell to increase the current in the thin amorphous silicon top cell [14,15]. As a result, the thickness of the a-Si H top cell can be reduced to improve the stability of the cell upon light induced degradation. Recent progress has even lead to improved light utilization and higher short circuit current density by an optimized intermediate reflector [16]. However, this intermediate reflector might consist of another material than ZnO. 

Fig. 4.8. Efficiency rj, open-circuit voltage Voc, and short-circuit current density jsc as a function of the band gap a of a 2-band system illuminated by blackbody radiation at 5 800 K with an incident energy current density of 1.39 kW/m2...

A plot of the current density versus voltage for the two devices is shown in Fig. 5.22. The open-circuit voltages of the cells are identical (0.82 V). However, the chlorobenzene-based device exhibits a more than twofold increase in the short-circuit current density as compared to the toluene-based... 

A useful convention is the fill factor FF. It is related to the maximum quantity of electrical energy extracted from the solar cell, characterised by an open-circuit photovoltage of Voc and a short-circuit current density Jsc. The fill factor for a device is described by... 

Deckman et al. (1983) have shown that the long-wavelength response of a-Si H solar cells can be increased by using textured surfaces to promote a light-trapping effect. They demonstrated that texturing can enhance the short-circuit current density of p-i-n cells by —25%. 

FF(0) Fill factor of cell with short-circuit current density extrapolated to zero... 

Here Jo is the dark saturation current density, Rs is the series resistance, A is the area and Rp is the shunt resistance. When a voltage V exists on the junction, the output current of the illuminated solar cell has two components, (1) the junction current density 7j (illumination) due to injection of carriers and (2) the short circuit current density Jsc due to light generated carriers. Therefore the output current density J v of the illuminated solar cell is given by,... 

Power conversion efficiency— is the ratio between output power and input power of a device. In - photovoltaic devices it denotes the ratio between the maximum electrical power supplied by a device and the incident radiant power. In this case it is given by rj = l7, " X, XFF, where Doc is the - open-circuit potential, Jsc is the - short-circuit current density, FF is the - fill factor, and E is the -y irradiance. 

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