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

Theuse of thin silicon (Si) wafers and streamlined fabricationmethods that can be scaled up without compromising device efficiencyis a key strategy for realizing low-cost and flexible solar cells.Herein, aluminum (Al)-catalyzed Si nanowires (NWs) formed by vapor-liquid-solidgrowth on paper-thin polished and etched Si(111) wafers of 100 and60 & mu;m thickness with high proficiency for minimizing interfacialdefects and light absorption loss have been accomplished. Successfullyaddressing the major challenge of rapid Al catalyst oxidation by exsitu and uncomplicated growth conditions allows for the potentialto scale up the process while preventing the formation of deep-leveltraps resulting from catalyst contamination. The Si NWs formed onthe nanowave surface of a thin etched Si wafer evidence comparablelight absorbance and low interfacial defects to those grown on thinpolished and traditional Si wafers. Fabrication of thin Si NW solarcells 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 significantradiative energy transfer by matching the light absorption range ofNCs with a high Stokes shift in the luminescence spectrum and thespectral response range of underlying Si solar cells. The nonradiativeenergy transfer efficiency of NCs and an NC amount infiltration onhomojunction Si NW solar cells for maximizing PCE enhancement wereexamined. The effective photon-harvesting architectures of NWs andNCs together with efficient energy transfers and surface passivationfrom NCs to the underlying homojunction Si NW solar cells could capablyenhance PCE up to a 9% level. These results exhibited the potentialfor feasible low-cost and large-scale fabrication techniques withlower consumption of raw materials for future photovoltaic applications.