In this article, we propose a modelling and optimization of an InxGa1-xN based PV solar cell in the frequency-dynamic regime under monochromatic illumination. We first elaborated a mathematical model of the InxGa1-xN based solar cell in order to study its behaviour when subjected to monochromatic illumination in the frequency-dynamic regime. We were able to establish the electrical parameters as a function of the pulsation and wavelength of the illumination. Next, we optimized the indium proportion as a function of the nature of the illumination by simulating the efficiency of the PV solar cell, for different wavelength of the illumination and values of the pulsation, as a function of the indium fraction. This enabled us to obtain, for an illumination pulsation ranging from 0 to 106 rad. s−1, the optimum values for the indium fraction, which are xop = 0.28 and xop = 0.26 respectively for wavelengths of 0.5 µm and 0.9 µm, corresponding to optimum efficiencies of 28.7% and 26.6% respectively. Above a pulsation of 106 rad. s−1, the increase in pulsation leads to an increase in the indium fraction, resulting in a decrease in efficiency for both short and long wavelengths.