Unveiling Structurally Engineered Carrier Dynamics in Hybrid Quasi-Two-Dimensional Perovskite Thin Films toward Controllable Emission

Shang, Qiuyu; Wang, Yunuan; Zhong, Yangguang; Mi, Yang; Qin, Liang; Zhao, Yuefeng; Qiu, Xiaohui; Liu, Xinfeng; Zhang, Qing

doi:10.1021/acs.jpclett.7b01857

Cited by 159 publications

(190 citation statements)

References 45 publications

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“…In addition, several groups have conducted ultrafast spectroscopic studies and found fast charge transfer in these complicated heterostructures. However, while charge transfers of ≈0.5 ps were detected in (C 10 H 7 CH 2 NH 3 ) 2 (FA) n −1 Pb n I 3 n +1 ( n ≥ 2) (Figure e–g) and (C 6 H 5 CH 2 CH 2 NH 3 ) 2 (CH 3 NH 3 ) n −1 Pb n I 3 n +1 ( n = 3 or 5), ≈500 ps processes were detected in (C 6 H 5 CH 2 CH 2 NH 3 ) 2 (CH 3 NH 3 ) n −1 Pb n I 3 n +1 ( n = 4) (Figure h,i) . It should be noted that the films studied in these reports had similar composition and geometry, and even highly similar domain distribution, while the relaxation time constants differed by orders of magnitude.…”

Section: Charge Transfer and Device Designmentioning

confidence: 97%

Merits and Challenges of Ruddlesden–Popper Soft Halide Perovskites in Electro‐Optics and Optoelectronics

et al. 2018

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Following the rejuvenation of 3D organic–inorganic hybrid perovskites, like CH3NH3PbI3, (quasi)‐2D Ruddlesden–Popper soft halide perovskites R2An−1PbnX3n+1 have recently become another focus in the optoelectronic and photovoltaic device community. Although quasi‐2D perovskites were first introduced to stabilize optoelectronic/photovoltaic devices against moisture, more interesting properties and device applications, such as solar cells, light‐emitting diodes, white‐light emitters, lasers, and polaritonic emission, have followed. While delicate engineering design has pushed the performance of various devices forward remarkably, understanding of the fundamental properties, especially the charge‐transfer process, electron–phonon interactions, and the growth mechanism in (quasi)‐2D halide perovskites, remains limited and even controversial. Here, after reviewing the current understanding and the nexus between optoelectronic/photovoltaic properties of 2D and 3D halide perovskites, the growth mechanisms, charge‐transfer processes, vibrational properties, and electron–phonon interactions of soft halide perovskites, mainly in quasi‐2D systems, are discussed. It is suggested that single‐crystal‐based studies are needed to deepen the understanding of the aforementioned fundamental properties, and will eventually contribute to device performance.

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Section: Charge Transfer and Device Designmentioning

confidence: 97%

Merits and Challenges of Ruddlesden–Popper Soft Halide Perovskites in Electro‐Optics and Optoelectronics

et al. 2018

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“…The charge carrier dynamics in (PEA) 2 (MA) n −1 Pb n I 3 n +1 perovskite were investigated by Shang et al by combining TAS, low‐temperature PL, and KPFM . This study unraveled that the multiple phases of perovskites were naturally arranged in the increasing order of n (from small to large) along the direction normal to the substrate and that different n perovskites also distribute within the same planes, parallel to the substrate.…”

Section: Photophysics Of 2d/3d Mixed Dimensional Perovskitesmentioning

confidence: 99%

Mixed Dimensional 2D/3D Hybrid Perovskite Absorbers: The Future of Perovskite Solar Cells?

Krishna

Gottis

Nazeeruddin

et al. 2018

Adv Funct Materials

298

269

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The cost-effective processability and high efficiency of the organic-inorganic metal halide perovskite solar cells (PSCs) have shown tremendous potential to intervene positively in the generation of clean energy. However, prior to an industrial scale-up process, there are certain critical issues such as the lack of stability against over moisture, light, and heat, which have to be resolved. One of the several proposed strategies to improve the stability that has lately emerged is the development of lower-dimensional (2D) perovskite structures derived from the Ruddlesden-Popper (RP) phases. The excellent stability under ambient conditions shown by 2D RP phase perovskites has made the scalability expectations burgeon since it is one of the most credible paths toward stable PSCs. In this review, the 2D/3D mixed system for photovoltaics (PVs) is elaborately discussed with the focus on the crystal structure, optoelectronic properties, charge carrier dynamics, and their impact on the photovoltaic performances. Finally, some of the further challenges are highlighted while outlining the perspectives of 2D/3D perovskites for highefficiency stable solar cells.external conditions in terms of temperature and humidity level, the perovskite can produce gases even at moderate temperatures (≈85 °C), causing thermal decomposition, layers cracking, and interfacial deterioration issues which cause irreversible performance fading. [26] Finally, under light exposure, MAPbI 3 can sustain internal ionic migration, which further adds to performance decline. [27] Two strategies have emerged to stabilize the perovskite, one of them being the incorporation of triple/quadruple cations within the A-site [28][29][30][31] and other being the development of lower dimensional perovskites. [32,33] The lower-dimensional 2D perovskites composed of alternating organic and inorganic layers called Ruddlesden-Popper (RP) phases having general formula A 2 A′ n−1 B n X 3n+1 . [34] 3D to 2D structural transition is controlled by the size of the organic cation, in particular when it exceeds the critical size of Goldschmidt's tolerance factor (TF). [34] The advantages of the layered 2D structure are multiple, e.g., 2D perovskites are thermally more robust, larger cations hamper internal ionic motion and can bring to the absorber the much needed hydrophobic character through adequate organic moieties leading to an improved stability. [35] However, these appealing features are overshadowed by more common optoelectronic properties such as a wider optical bandgap of at least 2.5 eV which restricts photons conversion to less than 500 nm [36,37] and by a larger exciton binding energy of ≈300 meV [36] (10-50 meV for 3D counterpart) which penalizes output photovoltage, therefore the power conversion efficiencies. The current record showed a noncertified PCE of 12.5% under standard AM 1.5G conditions with 60% of PCE retention over 2250 h stability under light, heat, and humidity stress. [38] This progress was achieved by mixing 3D with 2D Ruddlesden-Popper perovskit...

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“…Recently, the amplified spontaneous emission (ASE) and lasing behaviors of 2D RPPs have been demonstrated . However, the lasing is mostly obtained from solution‐processed spin‐coated thin films, in which multiple RPP components inevitably form with different bandgaps that drive cascade carrier transfer and may reshape the build‐up of population inversion . Also, the development of continuous‐wave or electrically driven RPP lasers central for practical applications is still challenging.…”

Section: Auger Decay Lifetime (τAuger) At High Excitation Fluence (P mentioning

confidence: 99%

“…The kinetics at the PB peaks are extracted and fitted by a biexponential function (Figure S8, Supporting Information): the fast (<20 ps) and the slow (>90 ps) decay channels may contribute to the thermalization process and radiative transition, respectively. Generally, owing to the absence of intercompositional charge transfer processes, the lifetimes of as‐exfoliated homologous thin flakes are longer than those of the solution‐processed spin‐coated RPP thin films consisting of multiple compounds . Figure f compares the PL spectra of bulk crystals (near Gaussian‐type) and exfoliated microflakes (near Gaussian‐type).…”

Section: Auger Decay Lifetime (τAuger) At High Excitation Fluence (P mentioning

confidence: 99%

Lasing from Mechanically Exfoliated 2D Homologous Ruddlesden–Popper Perovskite Engineered by Inorganic Layer Thickness

et al. 2019

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approach to realize new functionalities through facile van der Waals coupled 2D layers. [6] Owing to the large dielectric mismatch between the inorganic and organic layers, the quasi-2D RPPs naturally form quantum well structures, in which, the inorganic and organic layers serve as potential wells and barriers, respectively. [7] Moreover, these quantum confined structures impart the appealing characteristics of improved environmental stability and enhanced exciton confinement. [2] These make the quasi-2D RPPs promising for solar cell and light-emitting diode (LED) applications. [5,[8][9][10] Recently, the amplified spontaneous emission (ASE) and lasing behaviors of 2D RPPs have been demonstrated. [11][12][13][14][15][16][17] However, the lasing is mostly obtained from solution-processed spin-coated thin films, in which multiple RPP components inevitably form with different bandgaps that drive cascade carrier transfer and may reshape the build-up of population inversion. [11,14,15,18] Also, the development of continuous-wave or electrically driven RPP lasers central for practical applications is still challenging. The exploitation of homologous RPP lasers is of great importance to gain further insights into the intrinsic lasing mechanisms of these quantum well-like structures as well as the design of low-threshold 2D 2D Ruddlesden-Popper perovskites (RPPs) have aroused growing attention in light harvesting and emission applications owing to their high environmental stability. Recently, coherent light emission of RPPs was reported, however mostly from inhomologous thin films that involve cascade intercompositional energy transfer. Lasing and fundamental understanding of intrinsic laser dynamics in homologous RPPs free from intercompositional energy transfer is still inadequate. Herein, the lasing and loss mechanisms of homologous 2D (BA) 2 (MA) n −1 Pb n I 3n+1 RPP thin flakes mechanically exfoliated from the bulk crystal are reported. Multicolor lasing is achieved from the large-n RPPs (n ≥ 3) in the spectral range of 620-680 nm but not from small-n RPPs (n ≤ 2) even down to 78 K. With decreasing n, the lasing threshold increases significantly and the characteristic temperature decreases as 49, 25, and 20 K for n = 5, 4, and 3, respectively. The n-engineered lasing behaviors are attributed to the stronger Auger recombination and exciton-phonon interaction as a result of the enhanced quantum confinement in the smaller-n perovskites. These results not only advance the fundamental understanding of loss mechanisms in both inhomologous and homologous RPP lasers but also provide insights into developing low-threshold, substrate-free, and multicolor 2D semiconductor microlasers.2D Ruddlesden-Popper perovskites (RPPs), with the general chemical formula of L 2 (MA) n−1 M n X 3n+1 , are composed of welldefined inorganic layers with corner connected [MX 6 ] 4− octahedra and long organic chains (L + ) intercalated between these inorganic fragments. [1][2][3][4][5] This structure promises a viable

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Unveiling Structurally Engineered Carrier Dynamics in Hybrid Quasi-Two-Dimensional Perovskite Thin Films toward Controllable Emission

Cited by 159 publications

References 45 publications

Merits and Challenges of Ruddlesden–Popper Soft Halide Perovskites in Electro‐Optics and Optoelectronics

Merits and Challenges of Ruddlesden–Popper Soft Halide Perovskites in Electro‐Optics and Optoelectronics

Mixed Dimensional 2D/3D Hybrid Perovskite Absorbers: The Future of Perovskite Solar Cells?

Lasing from Mechanically Exfoliated 2D Homologous Ruddlesden–Popper Perovskite Engineered by Inorganic Layer Thickness

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