Single-Source Vapor Deposition of Quantum-Cutting Yb³⁺:CsPb(Cl_1–xBr_x)₃and Other Complex Metal-Halide Perovskites

Abstract

Metal-halide semiconductors exhibit attractive properties for a host of applications including photovoltaics, solid-state lighting, and photodetection. Among the remarkable recent developments is the discovery of extraordinarily high photoluminescence quantum yields in Yb3+-doped inorganic lead-halide perovskites. Although all previous research and development of such quantum-cutting materials has involved solution-phase preparation, particularly as colloidal nanocrystals, such methods can introduce both processing and technical challenges that limit the scope of accessible compositions, morphologies, and scaled-up applications. Here, we demonstrate a scalable single-source vapor deposition (SSVD) method for depositing high-quality conformal thin films of complex metal-halide perovskites, including doped perovskites, over large areas at high deposition rates. Focusing on quantum-cutting Yb3+:CsPb­(Cl1–x Br x )3, we demonstrate large-area deposition of films with photoluminescence quantum yields as high as 183%, starting from single-source powders prepared mechanochemically from solid ionic precursors. We also prepare thin films of the solar absorber material (FA0.81MA0.14Cs0.05)­Pb­(Cl0.02Br0.14I0.84)3 to illustrate the generality of this SSVD method. These results demonstrate a promising approach to high-throughput vapor processing of metal-halide coatings for photonic and optoelectronic applications.

Controllable deposition of organic metal halide perovskite films with wafer-scale uniformity by single source flash evaporation

“…The pre-synthesized MAPbI 3 single crystal powder was used as the source instead of PbI 2 and MAI precursors (see the inset of Fig. 1 b) in order to obtain better quality films owing to an exact stoichiometric ratio between the different ionic components of MAPbI 3 within the single crystal 30 , 45 . The exact amount of single crystal powder was loaded on the tungsten boat which is located inside of vacuum chamber.…”

“…The evaporation method, on the other hand, has a potential for uniform large-area film deposition 28 , 29 , conformal film deposition on uneven surfaces 30 , as well as a simple patterning with shadow masks 31 . Additionally, since it is a solvent-free process, there is no need to consider surface tension or solubility of the underlying layer.…”

“…Flash evaporation method has gained attention as a candidate for evaporating two or more precursors from a single thermal source by rapidly raising the temperature in a very short time 20 , 30 , 31 , 38 – 41 . In principle, the rapid vaporization of the precursors induces complete and uniform evaporation of the precursors, while maintaining the same ratio between the different components in OHP.…”

“…Solar cells with flash evaporated OHP films have exhibited over 10% of power conversion efficiency 39 , 41 , which is comparable to the early stage spin-coated OHP films 17 , 42 . Furthermore, the flash evaporation method has been expanded to deposit OHP films with mixed cation and halide species 30 , which is challenging for the aforementioned other evaporation methods 28 . Although this aspect of flash evaporation presents a prospect of exploring a diverse compositional range of OHPs, there has been relatively a few reports which have systematically studied the controllability of the flash evaporation method and the uniformity of OHP films produced by this method.…”

Tunable Wide‐Bandgap Monohalide Perovskites

“…Therefore, we decided to attempt the preparation of thin films by single-source vacuum deposition of the mechanochemicallysynthesized powders. [21,35,36] This technique allows for the processing of solid state materials in a simple and fast procedure that does not involve additional solvents or other chemicals. However, to limit possible thermal degradation of the material during the short heating phase, fully-inorganic compounds are preferred.…”