Question

3- Draw a typical JV curve of a solar cell in the dark and under illumination condition. Specify open circuit voltage and short circuit current. Draw the generated power by that cell under illumination condition. [5 marks] 4- A solar cell has a dark saturation current density of jo = 10-18 A/cm². If the photo-current is 0.024 A/cm² what is the open circuit voltage of the solar cell at room temperature? What happens to open circuit voltage as the solar cell gets warmed up when exposed to sun light? (does it go up or down?) [3 Marks]

Answer 1

dark and And :-3) Typical IV curve of a solar cell in under illumination condition: Dark Um I Voc L v Illuminated Im .. . - Iscy Here, Voc represent & Isc represent & shaded portion by solar cell open circuit voltage short circuit cursent represent generated power 19. dark saturation current density, jo=10 A/cm² photo current, j = 0.024 A1 cm² Voc at room temp (T- 200 1 ) Voc = nkt ln ( 11 ) assuming n=1 Voc = 1X 0.0258 en 1 0.07%+) = 0.0258% 34.71696 = 0.97309 V CS Scanned with Cams.canner

As, Voc = nkt en ( 3 ) The open circuit voltage decreases with temperative, because of dominent temperatue dependence of 'Jo'. The Jo from one side of pn junction dan Jo= q Dni? . q = electronic charge - A = area LNO D = diffusivity of minority I carriers L = minority carrier diffusion l length No = dloping concentration - ni intrinsic carrier whentration ni increases with increase in temperatue, so Jo te also increases which leads to decrease in open circuit voltage of solar cell. cs Scanned with CamScanner