Tuning crystal orientation and charge transport of quasi-2D perovskites via halogen-substituted benzylammonium for efficient solar cells

Cheng, Gui-Qiang; Wang, Jian; Yang, Rong; Li, Cheng; Zhang, Hao; Wang, Nana; Li, Renzhi; Wang, Jianpu; Huang, Wei

doi:10.1016/j.jechem.2021.07.033

Cited by 12 publications

(10 citation statements)

References 23 publications

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“…The best performance parameters of the device prepared at the precursor temperature of 20 °C are PCE = 12.43%, J SC = 16.69 mA/cm 2 , V OC = 1.06 V, and FF = 70.44%. The obtained device performance is one of the best results among the published data based on the BA quasi-2D perovskite systems without any modification. , It is found that the device PCE varies due to the film growth of inhomogeneity across from center to edge. The devices at sites C and D show significant reproducibility.…”

Section: Resultsmentioning

confidence: 68%

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Regulating Radial Morphology in Hot-Casting Two-Dimensional Ruddlesden–Popper Perovskite Film Growth for High-Efficient Photovoltaics

Dai

Qin

Huang

et al. 2023

ACS Appl. Energy Mater.

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Two-dimensional (2D) perovskites have attracted significant attention in recent years due to their promising light harvesting and emissive properties. However, the realization of 2D perovskite crystallization with sufficient coverage and reliable reproducibility remains difficult. In this study, controlling the solvent volatilization to achieve high-quality crystallization with full coverage and lateral homogeneity of 2D Ruddlesden–Popper phase perovskite was effectively achieved. It is found that variations in the solvent evaporation rate give rise to lateral film coverage gradients with the degree of grain fusion during the process of hot-casting. As a result, the obtained photovoltaic efficiency varies due to the growth inhomogeneity across hot-casting thin films from center to edge. By adjusting the temperature of the casting perovskite precursor, film inhomogeneity and device performance variation can be alleviated. Regulating radial morphology across hot-casting thin films will enable coating techniques amenable to the solution process for robust reproducibility.

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Section: Resultsmentioning

confidence: 68%

“…The obtained device performance is one of the best results among the published data based on the BA quasi-2D perovskite systems without any modification. 58,59 It is found that the device PCE varies due to the film growth of inhomogeneity across from center to edge. The devices at sites C and D show significant reproducibility.…”

Section: Resultsmentioning

confidence: 99%

Regulating Radial Morphology in Hot-Casting Two-Dimensional Ruddlesden–Popper Perovskite Film Growth for High-Efficient Photovoltaics

Dai

Qin

Huang

et al. 2023

ACS Appl. Energy Mater.

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“…The primary peaks of the control group (x = 0) at 14.28 and 28.58°correspond to the (111) and (202) crystal planes, respectively, which is consistent with the XRD findings. 47 As the Br content increases, the diffraction peak shifts to larger angles, indicating lattice shrinkage and a consequent structural change. For the x = 0.3 films, we conducted XRD measurements under dark−light−dark cycles, as shown in Figure 2b.…”

Section: Resultsmentioning

confidence: 99%

Vertical Halide Segregation and Stability of Two-Dimensional Layered Perovskite Nanostructures: Implications for Optoelectronic Devices

Qi,

Yang,

Wang

et al. 2023

ACS Appl. Nano Mater.

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Two-dimensional (2D) layered perovskites have garnered widespread attention due to their exceptional environmental stability and adaptable optical properties. However, quasi-2D layered perovskites typically undergo ion migration and phase segregation when illuminated, presenting a significant challenge in achieving stable optoelectronic devices. In this study, we employ time-dependent photoluminescence spectroscopy to investigate the photoinduced phase segregation of 2D perovskites and to explore the dependence of film stability on perovskite phases. Our results reveal that phase segregation is more likely to occur at the top side (film/air interface) than at the bottom side (film/substrate interface) of the 2D mixed halide perovskite film. We attribute this phenomenon to the 3D perovskite phase located at the top side of the film, which promotes the phase segregation, while the formation of the small-n phase at the bottom side inhibits the photoinduced phase segregation. The vertical alignment of different phases has a decisive effect on photoinduced phase segregation and, therefore, on the vertical stability of the film. These findings provide guidelines for optimizing the vertical stability of 2D mixed halide perovskite structures toward high-performance optoelectronics.

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“…9 Despite the dramatically enhanced stability, the PCE of Q-2D RP PSCs still lags behind that of their 3D counterparts due to the inferior charge transport in Q-2D perovskites resulting from the insulating nature of organic spacer layers. 10−14 Recently, several studies have demonstrated that fluorination of spacer cations, such as fluorinated phenylethyl ammonium (F-PEA), 15−20 fluorinated bromobenzyl ammonium (F-BBA), 21,22 and fluorinated aromatic formamidinium (F-ArFA), 23 can effectively enhance the PCE and stability of Q-2D RP PSCs. The proposed mechanisms for performance enhancement include the following: (1) the fluorination of spacer cations induces a vertically aligned crystal growth of perovskites, which facilitates efficient charge transport in Q-2D perovskite films; [17][18][19]22 recombination loss; 17,19,20 and (3) introduction of a fluorinated spacer cation could reduce the trap density and increase the carrier mobility in Q-2D RP perovskites.…”

Section: Introductionmentioning

confidence: 99%

“…Despite the dramatically enhanced stability, the PCE of Q-2D RP PSCs still lags behind that of their 3D counterparts due to the inferior charge transport in Q-2D perovskites resulting from the insulating nature of organic spacer layers. − Recently, several studies have demonstrated that fluorination of spacer cations, such as fluorinated phenylethyl ammonium (F-PEA), − fluorinated bromobenzyl ammonium (F-BBA), , and fluorinated aromatic formamidinium (F-ArFA), can effectively enhance the PCE and stability of Q-2D RP PSCs. The proposed mechanisms for performance enhancement include the following: (1) the fluorination of spacer cations induces a vertically aligned crystal growth of perovskites, which facilitates efficient charge transport in Q-2D perovskite films; − , (2) the fluorination promotes the formation of a type-II energy-level alignment between different perovskite phases, avoiding carrier trapping and thus recombination loss; ,, and (3) introduction of a fluorinated spacer cation could reduce the trap density and increase the carrier mobility in Q-2D RP perovskites. , However, there is still a lack of a deeper understanding of the relationship between fluorination of spacer cations and evolution of perovskite formation, and the effect of fluorination on the interaction between adjacent spacer cations has rarely been investigated.…”

Section: Introductionmentioning

confidence: 99%

Insight into the Enhanced Charge Transport in Quasi-2D Perovskite via Fluorination of Ammonium Cations for Photovoltaic Applications

Wang

Liu

Ren

et al. 2022

ACS Appl. Mater. Interfaces

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Fluorinated spacer cations in quasi-2D (Q-2D) perovskites have recently been demonstrated to improve the Q-2D perovskite solar cell (PSC) performance. However, the underlying mechanism of fluorination of organic cations on the improvement is still unclear. Here, using fluorinated benzylammonium (named F-BZA) as a spacer cation in Q-2D Ruddlesden–Popper (RP) perovskites, we deeply investigate the effect of fluorination of organic cations on perovskite crystallization and intermolecular interactions for improving the charge transport and device performance. It is found that fluorination of spacer cations can slow down the crystallization rate of perovskites, resulting in vertically aligned large grains. Moreover, the interaction between the adjacent spacer cations is further enhanced, constructing a new faster charge-transport channel with a lifetime of 77 ps. Accordingly, the carrier mobility is improved by an order of magnitude and a power conversion efficiency (PCE) of 16.82% is achieved in much more stable F-BZA-based Q-2D RP PSCs, 35% higher than that of BZA-based devices (12.39%). Our results elucidate the mechanism and its importance of fluorinating spacer cations for high-performance Q-2D PSC development.

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Tuning crystal orientation and charge transport of quasi-2D perovskites via halogen-substituted benzylammonium for efficient solar cells

Cited by 12 publications

References 23 publications

Regulating Radial Morphology in Hot-Casting Two-Dimensional Ruddlesden–Popper Perovskite Film Growth for High-Efficient Photovoltaics

Regulating Radial Morphology in Hot-Casting Two-Dimensional Ruddlesden–Popper Perovskite Film Growth for High-Efficient Photovoltaics

Vertical Halide Segregation and Stability of Two-Dimensional Layered Perovskite Nanostructures: Implications for Optoelectronic Devices

Insight into the Enhanced Charge Transport in Quasi-2D Perovskite via Fluorination of Ammonium Cations for Photovoltaic Applications

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