Chemical Vapor Deposition of Perovskites for Photovoltaic Application

Abstract

just a couple of years, suggesting a bright future for PV application. [15][16][17] To date, a number of processing technologies have been developed to fabricate perovskites, such as solution process, [2,3,[18][19][20][21] thermal evaporation, [22,23] flash evaporation, [24] atomic layer deposition (ALD), [25] doctor-blade coating, [26] slot-die coating, [27] spray deposition, [28] and ink-jet printing, [29] etc. Among various approaches, the most studied solution method not only achieves highly efficient PSCs but also owns cost advantage. However, the uncontrolled over-rapid liquid reaction often generates rough and porous films with incomplete conversions, resulting in large variations on film morphology and PV response. [18][19][20][21] Inversely, thermal evaporation can generate high-quality films with smooth and pinhole-free morphologies, in which the moderate gas-phase reaction characteristic effectively relieves the reaction rate. Nevertheless, there are a few of disadvantages in vacuum process, for instance, low material utilization, high equipment investment and energy consumption, hampering its further application. [22][23][24][25] The rest technologies often produce poor film quality, and are also difficult to scale up. [26][27][28][29] Therefore, development of a new class of advanced fabrication technology shall be critical for the future commercialization of PSCs.In 2013, a radically different technology, that is, vapor-assisted solution process (VASP), is invented by Yang and coworkers. [30] This method combines the advantages of gas-phase deposition and solution process. Concretely speaking, PbI 2 films are first spin-coated as the precursors, and then reacted with MAI vapor in a closed room. The attraction of this work is that film growth via in situ gas-solid (G-S) reaction, which is considered as a fruitful way for preparing perovskites. Subsequently, similar G-S crystallization and other modified VASP approaches are reported. [31][32][33] However, VASP methods require manipulations in glove box or protecting atmosphere, and show poor controllability and versatility, unsuitable for their mass production. Soon after, as an evolution of VASP, more convenient tubular CVD technology is successively developed by independent groups. [34][35][36] This simple and low-cost film growth method provides excellent controllability and repeatability for batch processing, which has been regarded as a cost-effective road for fabricating high-quality perovskites. Subsequently, an array of CVD techniques, such as in situ tubular CVD (ITCVD), [37] one-step tubular CVD, [38] aerosol-assisted CVD (AACVD), [39][40][41][42] hybrid physical-chemical vapor deposition (HPCVD), [43] modified chemical vapor transport (mCVT), [44] and so on, are consecutively invented, and remarkable achievements of PSCs by In recent years, high-efficient and low-cost perovskite solar cells (PSCs) have triggered a strong interest in the photovoltaic (PV) field. However, it is still challenging to develop cost-effective perovskite fabricatio...

Near‐Infrared‐Transparent Perovskite Solar Cells and Perovskite‐Based Tandem Photovoltaics

“…However, the high vapor pressure of organic halide component such as MAI, makes it challenging to attain a precise control over the evaporation rates of the precursors. [ 137 ] This can be circumvented by decoupling the deposition of the organic and inorganic precursors through adopting to a sequential deposition process.…”

Characterization of Methylammonium Lead Iodide Thin Films Fabricated by Exposure of Lead Iodide Layers to Methylammonium Iodide Vapor in a Closed Crucible Transformation Process

“…For all substrate temperatures working solar cells could be produced. However, with about 2.5%, even the best efficiencies are small compared to MAPI solar cells produced with comparable vapor deposition techniques with varying contact materials . Thereby, with V oc ≈0.95 V, J sc ≈76 A m −2 and a fill factor in the range of 0.31 for the best solar cells, the most severe problems appear to be low photo current densities and low fill factors.…”

“…Although the highest efficiencies are achieved with wet chemical methods, gas phase deposition methods provide interesting features. Those are, for example, good process control, uniform large area films, upscalability, and precise control of the layer thickness and layer properties . In addition, multilayer stacks are possible without restrictions to orthogonal solvents .…”

A Review of Perovskite Photovoltaic Materials’ Synthesis and Applications via Chemical Vapor Deposition Method

“…It should be pointed out that, the diffusion rate can be varied over a wide range by controlling its gas pressure when the growth temperature is limited to reasonable value for the HPCVD system. Thus, high-quality perovskite films with fully covered, smooth surfaces are achieved by using the HPCVD method [37,79]. A hybrid CVD with cation exchange method is developed for preparation of Cs-substituted mixed cation perovskite films [80,81,82].…”

“…Soon after, as an evolution of VASP, an array of CVD techniques [2,34,35,36,37,38,39]—such as one-step and two-step tubular CVD, in situ tubular CVD (ITCVD), aerosol-assisted CVD (AACVD), hybrid physical-chemical vapor deposition (HPCVD), plasma-enhanced CVD (PECVD), and so on—were developed to grow high-quality PPMs. At present, CVD of perovskites is a promising alternative to solution based methods of fabrication due to the relative ease of patterning, the ability to batch process, the wide range of material compatibility, and the potential for uniform large-area deposition.…”