Abstract
A mathematical model of quantum dot intermediate band solar cells (QDIBSCs) is investigated using two intermediate bands (IBs). These two IBs arise from the quantum dot (QD) semiconductor material within the bandgap energy. Some parameters such as the width of the QD (W-QD) and the barrier thickness or the inter-dot distances between the QDs (B-T) are studied to show their influence on the performance of the QDIBSC. The time-independent Schrodinger equation, which is solved using the Kronig-Penney model, is used to determine the position and bandwidth energies of the two IBs. In our proposed model, the cubic shape of the QDs from InAs0:9N0:1 and the barrier or host semiconductor material from GaAs0:98Sb0:02 are utilized. It is shown from the results obtained that changing the parameters W-QD and B-T has more influence on the bandwidth energy for the first IB, Delta 1, than in the case of the second IB, Delta(2). The optimum power conversion efficiencies (PCEs) of the QDIBSCs with two IBs for the model under study are 58.01% and 73.55% at 1 sun and maximum solar concentration, respectively. One can observe that, in the case of the two IBs, an improvement of the PCE is achieved.