A thermodynamic cycle for the solar cell

TL;DR

This paper introduces a thermodynamic cycle model for solar cells, viewing them as heat engines with a gas of electrons and a self-oscillating interface acting as a piston, aligning solar energy conversion with thermodynamic principles.

Contribution

It proposes a novel thermodynamic cycle model for solar cells using electron gas and a self-oscillating interface, offering a new perspective on their operation.

Findings

Model predicts self-oscillation behavior of the p-n interface.

Suggests testable consequences for thermodynamic efficiency.

Provides hydrodynamical analogy with toy boat engines.

Abstract

A solar cell is a heat engine, but textbook treatments are not wholly satisfactory from a thermodynamic standpoint, since they present solar cells as directly converting the energy of light into electricity, and the current in the circuit as maintained by an electrostatic potential. We propose a thermodynamic cycle in which the gas of electrons in the p phase serves as the working substance. The interface between the p and n phases acts as a self-oscillating piston that modulates the absorption of heat from the photons so that it may perform a net positive work during a complete cycle of its motion, in accordance with the laws of thermodynamics. We draw a simple hydrodynamical analogy between this model and the "putt-putt"' engine of toy boats, in which the interface between the water's liquid and gas phases serves as the piston. We point out some testable consequences of this model.