Pressing challenges of halide perovskite thin film growth

Abstract

The adoption of new thin-film materials in high-end technologies, such as monolithic tandem solar cells and integrated circuits, demands fabrication processes that allow a high level of control over film properties such as thickness, conformality, composition, and crystal structure. Achieving this with traditional optoelectronic materials, such as silicon, indium phosphide, gallium arsenide, silicon nitride, and several metal oxides, has opened the way for applications such as high-efficiency photovoltaics, light emitting devices, and integrated photonics. More recently, halide perovskites have demonstrated huge potential in optoelectronic applications, showing exceptional photovoltaic properties, light emission, and lasing performance. Common growth techniques for these halide perovskites have been solution-based methods. Optimized solution-based processes yield high quality thin films well-suited for applications, such as single-junction solar cells, but remain incompatible with integration into complex devices such as monolithic tandem photovoltaics and photonic circuits. Therefore, new fabrication methods allowing atomic, structural, and compositional precision with the conformal growth of hybrid and multi-compound halide perovskite thin films are of utmost importance for material exploration and for their application in complex devices. This Perspective reviews the progress on synthesis methods of halide perovskite thin films, discusses pressing challenges, and proposes strategies for growth control, versatile film deposition, monolithic device integration, epitaxial growth, and high-throughput synthesis to discover novel and non-toxic stable metal halide compositions.

Review of Interface Passivation of Perovskite Layer

“…A one- ( Figure 2 a) or two-step ( Figure 2 b) method is typically used to prepare high-performance PSCs [ 23 , 24 , 25 ]. Furthermore, the dual-source vapor deposition method, two-step continuous solution-vapor assisted deposition method, and other approaches have been applied to the optimization of perovskite films for improving the PCE of PSCs [ 15 , 26 , 27 ].…”

Progress and challenges on scaling up of perovskite solar cell technology

“…About the deposition of organic-inorganic hybrid PVKs, another method named resonance infrared matrix-assisted pulsed laser evaporation 107 should be mentioned, showing low laser-induced damage of organic material. A detailed description of the new pulsed laser-based method can be found in Soto-Montero's review 108 . Based on the film quality as well as stability mentioned above, PLD has a potential application for scalable deposition of PVKs, especially in terms of fully inorganic PVK deposition.…”

Scalable Production of Ambient Stable Hybrid Bismuth‐Based Materials: AACVD of Phenethylammonium Bismuth Iodide Films**

“…In addition, while spray coating has been utilized on large‐scale substrates, excessive variables in the coating process such as droplet size, substrate wettability and solvent boiling point make it challenging, [53,54] as well as crystallization conditions for materials with large organic cations [47,55] . Solvent‐free techniques such as thermal co‐evaporation and high‐low vacuum deposition can produce high quality and pin‐hole free films with large crystallites due to achievement of a slower rate, however the demand of high vacuum makes them energy consuming and pricey, [22,56] and high deposition temperatures in vacuum‐based methods have a high requirement on thermal stability of precursors [57] . The need for a simple and low‐cost method to produce thin films of hybrid perovskite or perovskite‐derived materials requires the development of solution‐based methods beyond spin‐coating or spray coating.…”

“…[ 47 , 55 ] Solvent‐free techniques such as thermal co‐evaporation and high‐low vacuum deposition can produce high quality and pin‐hole free films with large crystallites due to achievement of a slower rate, however the demand of high vacuum makes them energy consuming and pricey,[ 22 , 56 ] and high deposition temperatures in vacuum‐based methods have a high requirement on thermal stability of precursors. [57] The need for a simple and low‐cost method to produce thin films of hybrid perovskite or perovskite‐derived materials requires the development of solution‐based methods beyond spin‐coating or spray coating. Aerosol‐assisted chemical vapor deposition (AACVD) represents an attractive alternative, as its solution‐based methodology adds versatility to the CVD process allowing the use of relatively large organometallic precursors carried in small droplets by a stream of inert gas.…”