SCAPS-1D simulation of perovskite solar cells with hydroxyapatite scaffold for lead encapsulation and performance optimization

Perovskite-based solar cells are the leading candidates in the next-generation of photovoltaic technologies because of their high-power conversion efficiency (PCE) that they possess and their ease of fabrication. Most of the highly efficient perovskite-based solar cells have lead (Pb) in their absorber layer which raises environmental, and health concerns should the device undergo degradation or Pb leakage. In this study we employ lead encapsulation techniques by incorporating a hydroxyapatite (HAP) scaffold layer into the device structure aiming at preventing the Pb leakage while maintaining the performance and the high PCE of the device. The influence of the key HAP parameters including the thickness of the layer, donor concentration, defect density and the bandgap on the device is systematically analyzed and simulated using SCAPS – 1D. In addition, the impact of aluminum-doped zinc oxide (AZO), which will be the devices electron transport layer, and the bottom electrodes, specifically copper nanowires (CuNWs) and indium-doped tin oxide (ITO), were assessed to give the optimized parameters that could be used in experimental fabrication of the device. The optimized device configuration includes an AZO layer (2.3 μm), a HAP scaffold (0.25 μm) with a defect density of 10 ¹ ⁵ cm⁻³ , donor concentration of 10²¹ cm⁻³ , and a bandgap of 1.46 eV, alongside a perovskite absorber (CH3NH3PbI3) layer of 0.8 μm, simulated at 300 K. Under these conditions, the simulated device reached a PCE of 25.08 %, a fill factor (FF) of 87.05 %, a short circuit current (Jsc) of 26.39 mA/cm2, and an open-circuit voltage (Voc) of 1.09 V demonstrating the potential of HAP as a functional scaffold in perovskite solar cell designs with the potential of preventing any lead leakage as well as improving the efficiency of the cell. This work is the first of its kind to simulate the usage of HAP in a solar cell device.