Hierarchical i–p and i–n porous heterojunction in planar perovskite solar cells

Liao, Hsueh-Chung; Tsao, Cheng‐Si; Jao, Meng‐Huan; Shyue, Jing‐Jong; Hsu, Chun‐Hua; Huang, Yu‐Ching; Tian, Kuo-Yo; Chen, Charn-Yin; Su, Chun‐Jen; Su, Wei‐Fang

doi:10.1039/c5ta02184g

Cited by 15 publications

(19 citation statements)

References 59 publications

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“…We also apply a kinetic model to GIWAXS measurements on representative perovskite films to extract the activation energy for the formation of CH 3 NH 3 PbI 3‐ x Cl x . Our work advances upon existing X‐ray diffraction measurements on CH 3 NH 3 PbI 3‐ x Cl x and CH 3 NH 3 PbI 3 films by providing detailed access to the dynamics of structural changes during film processing over three orders of magnitude in length scale.…”

Section: Introductionmentioning

confidence: 91%

“…In contrast, in the two‐step process, a perovskite film is formed via the initial deposition of a film of a lead salt followed by its exposure to an organic halide, either in a vapor or a solution phase . Because both one‐step and two‐step procedures have been used to produce high performance PSCs, both continue to be investigated in order to understand the basic mechanisms of perovskite formation and thus identify routes for further improvements in PSC efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…We note that the first use of GISAXS for the investigation of organometal halide perovskite films was made by Schlipf et al, who undertook a detailed investigation of two‐step fabrication of planar CH 3 NH 3 PbI 3‐ x Cl x films and concluded that the length scales present in the final perovskite films were very similar to those observed in the initial PbI 2 film, suggesting that control of PbI 2 morphology is critical in controlling the morphology of the final perovskite film . Liao et al have also used ex situ GISAXS to investigate CH 3 NH 3 PbI 3 deposited via both one‐step and two‐step methods . Here, evidence of pores was observed within the perovskite crystal grains, with such pores being subsequently filled by the electron or hole transporting material that was deposited onto the perovskite film.…”

Section: Introductionmentioning

confidence: 99%

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Monitoring the Formation of a CH₃NH₃PbI_3–_xCl_x Perovskite during Thermal Annealing Using X‐Ray Scattering

Barrows

Lilliu

Pearson

et al. 2016

Adv Funct Materials

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These materials were fi rst explored in solar cells as recently as 2006 [ 1,2 ] and in solidstate solar cells as recently as 2012, [ 3,4 ] and have since seen an unprecedented increase in power conversion effi ciency (PCE). Building upon the initial results through device optimization and materials purifi cation, perovskite solar cells (PSCs) can now exhibit unstabilized PCEs in excess of 20%, signifi cantly outperforming competing classes of next generation photovoltaics. [ 5 ] In parallel with these developments, there has been a signifi cant improvement in the understanding of the physical properties of these materials. This not only includes the operating principles of different PSC architectures, but also fabrication methods compatible with large scale and low cost manufacturing. [6][7][8] Combining these factors, it is clear that organometal halide perovskites have signifi cant promise as a family of semiconductors for solar energy harvesting in commercial applications.To fabricate PSCs, a range of techniques have been employed for the deposition and formation of the light harvesting perovskite layer. These include vacuum deposition of the perovskite components [ 9 ] and solution deposition of perovskite precursor inks. [ 10 ] Two approaches can be adopted for solution deposition, commonly referred to as either "one-step" or "two-step" processing. In the one-step process, blends of a lead salt and an organic component (e.g., lead (II) chloride and methylammonium iodide) are dissolved in a common solvent such as dimethylformamide (DMF) or dimethyl sulfoxide and cast to form a thin fi lm, typically having a thickness of a few hundred nanometers. Following solution casting, thermal annealing is then used to create the perovskite structure. The simplicity of this approach has afforded the straightforward transfer of one-step processing from small area deposition methods (e.g., spin-casting) to techniques that are compatible with large-area substrates such as spray-coating [ 6,11 ] and inkjet printing. [ 12 ] In contrast, in the two-step process, a perovskite fi lm is formed via the initial deposition of a fi lm of a lead salt followed by its exposure to an organic halide, either in a vapor or a solution phase. [ 8,[13][14][15][16] Because both one-step and two-step procedures have been used to produce high performance PSCs, [16][17][18][19][20][21][22] both continue to be investigated in order to understand the basic mechanisms of perovskite formation and thus identify routes for further improvements in PSC effi ciency.Here, we characterize the formation of CH 3 NH 3 PbI 3− x Cl x via thermal annealing in air of a precursor fi lm prepared using the one-step procedure. A combination of 2D grazing incidence IntroductionIn recent years organometal halide perovskites have become the hot topic of solar cell research within the academic community. Grazing incidence wide and small angle X-ray scattering (GIWAXS and GISAXS) measurements have been used to study the crystallization kinetics of the organolead halide pero...

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Monitoring the Formation of a CH₃NH₃PbI_3–_xCl_x Perovskite during Thermal Annealing Using X‐Ray Scattering

Barrows

Lilliu

Pearson

et al. 2016

Adv Funct Materials

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“…[16c] In a previous report, the fractal morphology of MAPbI 3 films was explained by a fractal‐like diffusion of MAI into PbI 2 films. [17b] Based on these findings, we estimate that the mass fractal morphology on the 100 nm scale is formed by grain aggregation with the presence of voids in the films. The value of the exponent can give an estimate of the compactness of the perovskite domain arrangement, with a lower value corresponding to a less dense film .…”

mentioning

confidence: 90%

“…The scattering curves obtained from the GISANS measurements exhibit a power law scattering ( I ( q ) ∝ q y − α ) in the middle q y range (0.01–0.05 nm −1 ), corresponding to the mesoscale (80–300 nm, Figure S4b, Supporting Information), reflecting the characteristics of mass fractals (2 < α < 3) for all three samples. [16a,b,17a] The mass fractal reveals a self‐similar packing of domains as schematically illustrated in inset of Figure g. [16c] In a previous report, the fractal morphology of MAPbI 3 films was explained by a fractal‐like diffusion of MAI into PbI 2 films.…”

mentioning

confidence: 92%

Preferential Orientation of Crystals Induced by Incorporation of Organic Ligands in Mixed‐Dimensional Hybrid Perovskite Films

Wang

Manzi

Wang

et al. 2018

Advanced Optical Materials

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Organic-inorganic perovskites demonstrate great potential for optical applications due to their intriguing optical and optoelectronic properties. Dedicated efforts have been carried out to understand the energy landscape and charge carrier mobilities for perovskite 2 materials. In order to further boost these materials toward large-scale applications, an alternative "bottom-up" route for the understanding about correlation between the morphology of high-quality planar films and its optical properties is essential. Here, mixed dimensional bromide-based hybrid perovskite thin films are prepared from a simple one-step solution processing route using mixtures of methylammonium bromide (MABr) and octylammonium bromide (OABr). Grazing incidence scattering (GIS) data statistically reveals that the development of thin film morphology as well as crystal orientation depends on the orientation of the OABr crystallites. Our study opens up further insight into the morphology of perovskite thin films. In combination, the occurrence of amplified spontaneous emission (ASE) in perovskite films with low ASE thresholds with values approaching 17.8 µJ/cm 2 is demonstrated and appears to be closely correlated to the tailored morphology, highlighting its importance for realizing optical gain media.

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Structure of Organometal Halide Perovskite Films as Determined with Grazing‐Incidence X‐Ray Scattering Methods

Schlipf

Müller‐Buschbaum

2017

Advanced Energy Materials

135

115

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Grazing‐incidence X‐ray scattering (GIXS) methods have proven to be a valuable asset for investigating the morphology of thin films at different length scales. Consequently, GIXS has been applied to the fast‐progressing field of organometal halide perovskites. This exciting class of materials has propelled research in the areas of cheap and sustainable photovoltaics, light emitting devices, and optoelectronics in general. Especially, perovskite solar cells (PSC) have seen a remarkable rise in power conversion efficiencies, crossing the 20% mark after only five years of research. This research news outlines GIXS studies focusing on the most challenging research topics in the perovskite field today: Current–voltage hysteresis, device reproducibility, and long‐term stability of PSC are inherently linked to perovskite film morphology. On the other hand, film formation depends on the choice of precursors and processing parameters; understanding their interdependence opens possibilities to tailor film morphologies. Owing to their tunability and moisture resistance, 2D perovskites have recently attracted attention. Examples of GIXS studies with different measurement and data analysis techniques are presented, highlighting especially in‐situ investigations on the many kinetic processes involved. Thus, an overview on the toolbox of GIXS techniques is linked to the specific needs of research into organometal halide perovskite optoelectronics.

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Hierarchical i–p and i–n porous heterojunction in planar perovskite solar cells

Abstract: A hierarchical pore network is discovered in CH3NH3PbI3 perovskite solar cell, which forms an i–p or i–n porous heterojunction with infiltrated hole transporting materials or electron transporting materials, respectively.

Cited by 15 publications

References 59 publications

Monitoring the Formation of a CH₃NH₃PbI_3–_xCl_x Perovskite during Thermal Annealing Using X‐Ray Scattering

Monitoring the Formation of a CH₃NH₃PbI_3–_xCl_x Perovskite during Thermal Annealing Using X‐Ray Scattering

Preferential Orientation of Crystals Induced by Incorporation of Organic Ligands in Mixed‐Dimensional Hybrid Perovskite Films

Structure of Organometal Halide Perovskite Films as Determined with Grazing‐Incidence X‐Ray Scattering Methods

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Hierarchical i–p and i–n porous heterojunction in planar perovskite solar cells

Abstract: A hierarchical pore network is discovered in CH3NH3PbI3 perovskite solar cell, which forms an i–p or i–n porous heterojunction with infiltrated hole transporting materials or electron transporting materials, respectively.

Cited by 15 publications

References 59 publications

Monitoring the Formation of a CH3NH3PbI3–xClx Perovskite during Thermal Annealing Using X‐Ray Scattering

Monitoring the Formation of a CH3NH3PbI3–xClx Perovskite during Thermal Annealing Using X‐Ray Scattering

Preferential Orientation of Crystals Induced by Incorporation of Organic Ligands in Mixed‐Dimensional Hybrid Perovskite Films

Structure of Organometal Halide Perovskite Films as Determined with Grazing‐Incidence X‐Ray Scattering Methods

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Monitoring the Formation of a CH₃NH₃PbI_3–_xCl_x Perovskite during Thermal Annealing Using X‐Ray Scattering

Monitoring the Formation of a CH₃NH₃PbI_3–_xCl_x Perovskite during Thermal Annealing Using X‐Ray Scattering