(581e) A General Processing Method for the Low-Cost Deposition of Quantum-Cutting and Metal-Halide Thin Films for High Efficiency Photovoltaics

The remarkable and highly tunable optoelectronic properties of metal-halide perovskites have driven extensive academic and industrial interest due to metal-halide perovskite’s exceptional performance in photovoltaics, light-emitting diodes, x-ray scintillators, photodetectors, etc. One uniquely promising material is Yb³⁺-doped CsPb(Cl_1-xBr_x)₃, which exhibits photoluminescent quantum yields approaching 200% via a quantum-cutting mechanism. Because the near-infrared emission from the Yb³⁺ dopant is well-matched to the bandgaps of silicon and CIGS, Yb³⁺:CsPb(Cl_1-xBr_x)₃ nanocrystals or thin films can act as a highly efficient quantum-cutting downconversion material to significantly boost the power conversion efficiency of commercial photovoltaic modules. Due to the low cost margins for utility-scale solar, the ability to solution process these materials has often been touted as an advantage. However, solution-processing has severe reliability challenges due to pinhole formation, poorly soluble precursors, inability to coat textured substrates, and substrate-solvent limitations.

Here, we present vapor-based single-source flash sublimation as a promising, general alternative to solution-based metal halide processing. We demonstrate the successful deposition of a wide range of different materials for a range of optoelectronic applications, including photovoltaics and quantum-cutting downconversion. In light of the tunable optoelectronic properties of Yb³⁺:CsPb(Cl_1-xBr_x)₃, we optimize deposition of this downconversion material for different photovoltaic technologies. We conclude with some initial device results, illustrating the versatility of flash sublimation and the high optoelectronic quality of metal-halide films it produces.