Majority carriers in an n-type material are electrons and its minority carriers are holes. Majority carriers in a p-type material are holes and therefore its minority carriers are electrons. The illuminated characteristics of the current are the same as the regular diode (or dark) characteristics, but shifted down by the current IL.Ī majority carrier is the charge carrier that determines current. Introduction Modeling PV Cells, Panels and Arrays General Equation of Solar-Induced Current (Output Current of Solar Cell) Temperature Dependence 5. IL is related to the photon flux incident on the cell and is dependent on the wavelength of the incident light. W is the width of the depletion region and is found by standard diode equations. Where Io is the same as in Equation 5.4 and IL is defined by the expression Adding Jh and Je gives the following result: Pn (x ) = Pno + gopTh + eXP – XĪgain, a similar expression defines Je. The particular solution to the equation is Where Th is the minority carrier lifetime. The general solution to this differential equation is The typical diode equations for determining the excess minority carrier concentrations include an additional term relating gop as follows:īecause g is constant, - is also constant. The assumption is made for solar cells that the generation rate of electron-hole pairs by the light (gop) is constant throughout the device. Q = the magnitude of the electronic charge (same as in Equation 5.2) kB = Boltzmann’s constant (kB) (can also simply use “k”) Na = the acceptor concentration in the p-region Nd = the donor concentration in the n-region П = intrinsic carrier concentration Dh = diffusion coefficient of the holes De = diffusion coefficient of the electrons Le = diffusion length (how far into the material before electrons diffuse) of the electrons Lh = diffusion length of the holes A = the cross-sectional area of the diode Where Io, the saturation current density, is given by The ideal diode law is expressed as the following equation: In order to derive the ideal current-voltage characteristics of a p-n junction diode when illuminated by light, mathematical results from the ideal diode equation are combined with the illuminated characteristics of the solar cell.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |