hmmm... (1 Viewer)

[CoNFuSeD]

Is there actually any use of the photoelectric effect in solar cells??

from what i've read it points to no, but i have an assignment that wants 6 marks worth of explanation of how it is used...

any help much appreciated

 

[wahashtini]

A solar cell has a layer of n-type silicon overlaying a layer of p-type silicon. Some conduction electrons in the n-type material will be attracted to the positive holes in the p-type, setting up an electric field over the junction. Now, if a photon of light of suitable energy strikkes an atom by the photoelectric effect. This produces an extra free electron from the atom by the photoelectric effect. This produces an extra free electron and a positive hole. The electric field will sweep the electron to the n-type side, and the hole to the p-type side. The only way they can recombine (because of the electric field acroos the junction) is for the electron to go through an external circuit to the p-type side i.e. the cell has generated an external current.
I copy pasted this from a HSC trial solution, similar to ur question,
still CoNFuSeD

 

[t-i-m-m-y]

note: the photoelectric effect in its simplest form is no longer used in solar cells. what we do see is a n-p junction which acts to direct the current. altho light is still used to "exicte" the electroncs, as wahastini pointed out above

 

[kheir]

sorry to interupt but isnt it the other way round first a depletion zone occcurs so the n type develops a wall of positive cahrges and p type develops a wall of negative charges. this is before anything happens. then when sunlight hits an electon is excited from the p type negative wall and into the n type. it seems weird however the electron is a bsorbed by the n type because of the positive wall in the depletion zone. the electric current continues to flow because the rest of the n type is negative and pushes it to the external circuit , this negative charge in the external circuit is thne pulled towardas the p type and a cycle forms. plz consider this explanation and draw diagram to try an dunderstand its difficult to see wat im tlakin about however its the only explaantiaon i can think of that doeasnt allow a build up of cherges somewhere. if im wrong plz tell me

 

[ashtor]

nah mate...thats exaclty what wahashtini explained

 

[wahashtini]

WLEKKK HHHHHHHHHHHSSSSSSSSSSSSSSEEEEEEEEEEEENNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN,
sed boozak ya kheir, fahemmmm 3amoooo
wat a sad case, types up a whole paragraph, and gets hammered by ASHTOR, in half a line, A3AJEBIIIIII

 

[mr EaZy]

Originally posted by kheir
sorry to interupt
if im wrong plz tell me

Sure, a depletion zone does set up a potential as E =V/d i think.
Electrical charges like electrons receive a force E =f/q
-ve Cherges move to n type and forces electrons out
onto the wires

one photon releases one electron and hole

many photons trigger a whole chain of electron movement

 

[aloquacious]

lol... reading all that stuff made ME confused... if u want a quick explanation here goes...

photoelectric effect IS used in solar cells. Basically light acts like a particle. It strikes the surface of the cell, transfers energy, excites the electrons in the atoms of the cell.

Then the eletrons start a current.

Hope this is right/has helped. Good luck with ur assignment

~aloquacious