Paper-Thin Al-Catalyzed Si Nanowire Solar Cells and Efficiency Enhancement by Hybrid Nanostructures with Mn-Doped Perovskite Nanocrystals

The use of thin silicon (Si) wafers and streamlined fabrication methods that can be scaled up without compromising device efficiency is a key strategy for realizing low-cost and flexible solar cells. Herein, aluminum (Al)-catalyzed Si nanowires (NWs) formed by vapor–liquid–solid growth on paper-thin polished and etched Si(111) wafers of 100 and 60 μm thickness with high proficiency for minimizing interfacial defects and light absorption loss have been accomplished. Successfully addressing the major challenge of rapid Al catalyst oxidation by ex situ and uncomplicated growth conditions allows for the potential to scale up the process while preventing the formation of deep-level traps resulting from catalyst contamination. The Si NWs formed on the nanowave surface of a thin etched Si wafer evidence comparable light absorbance and low interfacial defects to those grown on thin polished and traditional Si wafers. Fabrication of thin Si NW solar cells with a homojunction p+–p–n–n+ structure toward the enhanced power conversion efficiency (PCE) by hybrid nanostructures with manganese-doped cesium lead chloride (CsPb0.81Mn0.19Cl3) perovskite nanocrystals (NCs) using a simple drop-casting method has been explicitly explained. The precise tuning of the energy band and NC size enabled a significant radiative energy transfer by matching the light absorption range of NCs with a high Stokes shift in the luminescence spectrum and the spectral response range of underlying Si solar cells. The nonradiative energy transfer efficiency of NCs and an NC amount infiltration on homojunction Si NW solar cells for maximizing PCE enhancement were examined. The effective photon-harvesting architectures of NWs and NCs together with efficient energy transfers and surface passivation from NCs to the underlying homojunction Si NW solar cells could capably enhance PCE up to a 9% level. These results exhibited the potential for feasible low-cost and large-scale fabrication techniques with lower consumption of raw materials for future photovoltaic applications.