Question

Example 1 Calculate the energy transferred by photon (Eph or E) for a monochromatic radiation with wavelength of: Photon Energy hc E = a h is planck constant, C velocity of light in vaccum (m/s) and is wavelength of radiation (m) 0.4 um 1.08 um 1.8 um a) b) c) [Assume that h = 4.1358 x 10-15 eV and C = 3 x 108 m/s] Example 2 Consider a 100 cm2 photovoltaic cell with reverse saturation current lo= 10-12 A/cm2. In full sun, it produces a short-circuit current of 40 mA/cm2 at 25 C°. a) Find the open-circuit voltage at full sun and again for 50% sunlight. b) Plot the results. KT Voc = - In (1+1) = 0.0257 In (1 + :) 9 K = 273 + Cº Isc = 40mA/cm2x 100 cm2 = 4000 mA = 4A Full sun = 100% Example 3 An array of solar cells is to be connected to deliver 4 Amperes at 12 Volts under a typical light intensity. If each cell delivers 0.8 Amperes at 0.6 Volts: . Calculate the number of cells. With the aid of a schematic diagram, discuss in brief how the cells should be connected.

Answer 1

0.0257 Innlit 4000 8103 Solution 1) E = he i h= 4.1358.910-92 15 ev. C = 30/08 ms X = 0.4 pm E- (41358710-15)(31108) ale = 3.101850V (0.4810-6) E = (4.1358 X10-15) (3108) ::x= 1:08pm ? Cl. D.8 x 10-6) EFT. 149 ev c ) a = 1.8 spm E = 4.135.8 110 016-5)/3 * 903) (1.87106) E=0.6893pv 2 Given, Area (A = 100cm 2 10 = 10-12 A/com Isc A =.400 Alcom? 9). Full-Sun (100%) ISC = (4001A) (100) 4000 mA Voca 10-12 X 100 Voc 0.6274 V Half-Sun (50%) Isc = (0.5) (40mA) (100)= 2mA. 0.0257 10 / 1+ endir 2 10-12*100 VOC Voc = 0.60960