Intrinsic losses, including below-band gap, thermalization, mismatch angle, Carnot, and emission, are investigated in a structure of quantum dot intermediate band solar cells (QD-IBSCs). Owing to the excellent irradiance resistance of III-nitride material and reduction of Auger recombination processes, diluted nitride of InAsN is considered as quantum dot (QD) material. Then, AlPSb is considered as the barrier material according to the principles of intermediate band operation and the band structures of InAsN and AlPSb in which phosphorous molar fraction is optimized by the minimizing of total intrinsic losses. The engineering of QD size and period offers a way to engineer the confined energy levels within the QDs and ultimately the intrinsic losses. This was carried out with the help of a finite element model in the context of a three-dimensional Schrödinger equation created by means of MATLAB software and tight binding method, resulting in the minimum intrinsic loss of 55.18% for the InAs_0.995N_0.005  /  AlP_0.7 Sb_0.3 QD-IBSC at 1-sun concentration.

The uses of solar energy instead of fossil fuels to supply the global energy demand demonstrate the importance of developing solar cells. Among all solar cells, colloidal quantum dot solar cells have attracted particular attention due to their easy fabrication, size control, low cost, and flexibility. The depleted heterostructure solar cell is introduced and simulated using quantum dots of CdS and TiO₂ layers. Then, the Schrödinger equation is solved in the spherical polar coordinate and using the obtained eigenfunctions and eigenvalues, the absorption coefficient of other structural parameters are obtained by finite-difference time-domain method. Then solving Maxwell and Poisson equations using the electric field emitted from sunlight radiation, the generation rates of carriers and the current density and other characteristics of the solar cell based on introduced structure are obtained. For studied structures, the obtained optimum results are J_sc  ≈  15  mA  /  cm² and η  ≈  7  %  . The obtained values are relatively good in comparison with the experimental results for similar materials.