Role of Quantum Mechanics and Thermodynamics in solar cell?

[says]

What is the role of Quantum Mechanics and Thermodynamics in solar cell operation?

Is quantum mechanics the photovolatic effect, and thermodynamics the cell efficiency?

 

[Simon Bridge]

These are fields of physics: they have no special role in the photocell but they do provide models for understanding it's operation.
The cell, as does everything, has to obey the associated laws.

The photovoltaic effect is quantum mechanical - well done.
http://solarwiki.ucdavis.edu/The_Science_of_Solar/Solar_Basics/A._Introductory_Physics_for_Solar_Application/I._Atoms_and_Materials/1._Basics_of_Quantum_Theory

Thermodynamics is about heat: the cell heats up when it is used.
Even without this, the efficiency would be smaller than 1... but the laws of thermodynamics do set the efficiency limits.
http://link.springer.com/chapter/10.1007/978-3-662-09115-9_14#page-1

It would help you get better replies if you provided some context.