Design and simulation of n-type solar cells based on an iodine-doped CdTe absorber using SCAPS-1D

The performance of conventional p- type CdTe solar cells has plateaued in recent years, motivating exploration of n- type absorbers. Here, we evaluate a homojunction solar cell employing iodine-doped CdTe (CdTe:I) as the absorber in a Ti 3 C 2 T x MXene/ p -CdTe:As/ n- CdTe:I/indium structure through SCAPS-1D simulations and prototype devices. Optimized simulations predict efficiencies above 25% for thin CdTe:I absorbers (∼0.7 μm). In contrast, the first prototype achieved only ∼1.36% efficiency with V OC = 0.48 V, J SC = 6.45 mA/cm 2 and FF = 43.8%. When the simulation is adjusted to match the actual device structure, and the effective illumination is reduced to account for front-side light loss, the predicted V OC (0.48 V) and J SC (6.74 mA/cm 2 ) closely reproduce the experimental values. This suggests that the device performance is primarily limited by reduced front-side photon transmission and other material non-idealities. These results highlight the promise of iodine-doped n -type CdTe and identify clear pathways for further efficiency improvement.