Factors determining the vertical orientation of two-dimensional perovskites

Arai, Ryosuke; Yoshizawa‐Fujita, Masahiro; Takeoka, Yuko; Rikukawa, Masahiro

doi:10.1039/c9ce00631a

Cited by 17 publications

(22 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It should be noted that our films were too thin compared to the photoactive layer employed in photovoltaics. The small thickness could limit the growth of vertically standing phases converted from stable intermediate complexes, unlike the thick films in which phases can be perpendicularly oriented by slow crystallization …”

Section: Resultsmentioning

confidence: 99%

“…We propose that the stability of intermediate complexes can be a factor in controlling the orientation of crystal phase. It is worth mentioning that our thin films were deposited by antisolvent (chlorobenzene) dripping during spin‐coating in a water‐free environment, because those can also affect phase orientation . The previous studies reported that for large‐ n phases, the orientation of the perovskite seeds produced at the interface with atmosphere strongly influences that of the phases in the resulting films .…”

Section: Resultsmentioning

confidence: 99%

“…Structurally isolated quasi‐2D perovskite phases, each of which has its own excitonic characteristics, are formed with a nonuniform distribution in a solution‐processed film . The distribution of quasi‐2D perovskite layer numbers ( n ) has been found to be sensitive to the processing conditions such as various stoichiometric or nonstoichiometric mixing ratios for precursors, antisolvents, solvents, hot‐casting, film thickness, and spin‐coating conditions . As such, it is important to understand how quasi‐2D phases are assembled, and how their processing‐controlled phase compositions underpin the optoelectrical properties of the resulting films .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Controlling Spatial Crystallization Uniformity and Phase Orientation of Quasi‐2D Perovskite‐Based Light‐Emitting Diodes Using Lewis Bases

Han

Park

Wang

et al. 2019

Adv Materials Inter

View full text Add to dashboard Cite

Crystallographic orientation has a significant impact on the optoelectronic properties of films of quasi‐2D perovskite quantum wells. Here, oxygen‐bearing Lewis bases are employed as additives to explore their ability to modulate spatial uniformity of crystallization and orientation of crystal phases. Different Lewis bases added into the precursor solutions incorporating the large organic ammonium cation, phenethylammonium (PEA+), lead to different crystallization kinetics, which are attributed to the varying stability of intermediate complexes. The microscopic photoluminescence heterogeneity and 2D X‐ray diffraction patterns of the thin films reveal that inclusion of Lewis bases can lead to spatially more uniform crystallization and random orientation, resulting in an enhancement in light‐emitting diode performance. In contrast, quasi‐2D phases formed without Lewis bases show poorer uniformity and preferentially vertical orientation. Comparing the Lewis base properties such as Mayer order unsaturation and polarizability suggests that the ability to weakly coordinate with lead and strongly interact with the large organic ammonium is a key factor in controlling the phase composition favorably toward highly luminescent light‐emitting diodes. This work may be of help to provide insight of what kinds of Lewis bases can be helpful to realize the desired phase composition for high performance of optoelectronic applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Controlling Spatial Crystallization Uniformity and Phase Orientation of Quasi‐2D Perovskite‐Based Light‐Emitting Diodes Using Lewis Bases

Han

Park

Wang

et al. 2019

Adv Materials Inter

View full text Add to dashboard Cite

show abstract

“…Therefore, studying the crystallization kinetics of 2D perovskite is curial to effectively control the film forming process and adjust the crystal orientation (perpendicular to the substrate), which can effectively avoid or reduce the adverse effects of the organic molecular layer and improve device efficiency. [ 47,48 ] Nevertheless, few review articles were published on this subject.…”

Section: Introductionmentioning

confidence: 99%

Crystallization Kinetics in 2D Perovskite Solar Cells

Wang

Lei

et al. 2020

Advanced Energy Materials

140

124

View full text Add to dashboard Cite

volatile decomposition [23] or halide segregation are often observed in hybrid perovskites under various stress conditions (light, [24] thermal, [25] and electric fields [26]); 4) spontaneous phase transition easily occurs for perovskite with unstable crystal structures, particularly for inorganic perovskite. [27-29] To improve the stability of PSCs, researchers attempted numerous methods such as encapsulation, [30] additive engineering, [31] component engineering, [32] etc. [33] However, the PSCs' stability is yet to achieve a perfect solution. Recently, researchers found that the introduction of long-chain organic cations in 3D perovskite as 2D perovskite can block water and oxygen molecules, meanwhile, generate a steric effect to prevent phase transitions, and limit ion migration. [34-36] Hence, fabricating 2D [37,38] or 2D/3D [39-43] mixed perovskite as absorbing layers are effective approaches to improve the stability of PSCs. However, the PCE of 2D PSCs remain lower than that of the 3D ones, which is mainly attributed to the introduction of organic macromolecules that blocks the effective extraction and transport of carriers. [44,45] Fortunately, 2D perovskite usually has three arrangements, namely parallel, perpendicular to the glass substrate or randomly arranged. [46] Manipulating the orientation of the crystal and the phase distribution in the 2D solution-processed perovskite can improve the efficiency and reproducibility of the device. Among them, the most desired arrangement for PSCs is the one that perpendicular to the substrate. Therefore, studying the crystallization kinetics of 2D perovskite is curial to effectively control the film forming process and adjust the crystal orientation (perpendicular to the substrate), which can effectively avoid or reduce the adverse effects of the organic molecular layer and improve device efficiency. [47,48] Nevertheless, few review articles were published on this subject. In this review, we mainly focus on the key issue for controlling crystallization kinetics and summarizing the research progress of their effects on various types of 2D PSCs. We also discuss the crystal/natural quantum well (QW) structure and the original stability for 2D PSCs in detail. Finally, remaining challenges and outlooks are presented. 2. Crystal and Natural Quantum Well Structure The material structure has a substantial impact on performance. [49-51] Properties of 2D and 3D perovskites differ 2D perovskites demonstrate higher moisture stability, oxygen content, thermal stability, and a significantly lower ion migration/phase transition occurrence in comparison to 3D perovskite. These advantages imply huge potential for 2D perovskite in commercial applications in the photovoltaic field. However, the horizontal arrangement of the organic layer severely hinders the transport of carriers, and thus, the power conversion efficiency of 2D perovskite solar cells (PSCs) is significantly lower than that of 3D. Controlling the crystallization orientation to achieve rapid carrier transport can effe...

show abstract

“…[22][23][24][25] The desired average crystallographic orientation of (quasi-) 2D perovskite films can, to a large extent, be obtained through tuning of the deposition process, for example, by tuning the deposition temperature, atmosphere, or chemical composition of the precursor solution. [11,20,[26][27][28] In addition to the average crystallographic orientation, the microstructure of perovskite films has a marked impact on its optoelectronic properties. An increase in the average grain size, for instance, is often associated with increased device performance due to a reduction of trap-assisted recombination at grain boundaries.…”

mentioning

confidence: 99%

Unraveling the Microstructure of Layered Metal Halide Perovskite Films

et al. 2020

View full text Add to dashboard Cite

3D metal halide perovskites take on the form ABX 3 , in which A is typically either a small organic cation such as methylammonium or formamidinium or an inorganic cation such as cesium, B is a divalent metal, and the X-site is occupied by a halide ion. Following the success of these 3D metal halide perovskites, attention has recently (re)turned to their lowdimensional counterparts as a promising class of materials for a variety of optoelectronic applications. [1] Most notable of these are the layered metal halide compounds that take on the form A 2 BX 4. In these perovskitelike structures, layers of inorganic octahedra are separated by relatively large organic cations that act as an insulating barrier, thereby forming a natural quantum-well structure. [2,3] By adjusting the thickness or composition of the inorganic layer or organic cations, fundamental material parameters such as the bandgap, effective mass, and exciton binding energy can be tuned to cover a wide range of values. [4] The strong quantum and dielectric confinement in these layered 2D perovskites generally give rise to narrow excitonic luminescence spectra that make these materials particularly attractive candidates for the fabrication of color-pure light-emitting diodes and lasers. [5-8] In addition, despite their large exciton binding energies, 2D perovskites are also increasingly used in solar cells where the addition of small quantities of 2D perovskites is found to increase the thermal and ambient stability as well as the crystallinity of the 3D perovskite film.

show abstract

Factors determining the vertical orientation of two-dimensional perovskites

Abstract: Factors determining the orientation of two-dimensional perovskites were examined.

Cited by 17 publications

References 41 publications

Controlling Spatial Crystallization Uniformity and Phase Orientation of Quasi‐2D Perovskite‐Based Light‐Emitting Diodes Using Lewis Bases

Controlling Spatial Crystallization Uniformity and Phase Orientation of Quasi‐2D Perovskite‐Based Light‐Emitting Diodes Using Lewis Bases

Crystallization Kinetics in 2D Perovskite Solar Cells

Unraveling the Microstructure of Layered Metal Halide Perovskite Films

Contact Info

Product

Resources

About