Direct Vapor Growth of 2D Vertical Heterostructures with Tunable Band Alignments and Interfacial Charge Transfer Behaviors

Zheng, Weihao; Zheng, Biyuan; Yan, Changlin; Liu, Ying; Sun, Xingxia; Qi, Zhaoyang; Yang, Tiefeng; Jiang, Ying; Huang, Wei; Fan, Peng; Jiang, Feng; Ji, Wei; Wang, Xiao; Pan, Anlian

doi:10.1002/advs.201802204

Cited by 103 publications

(96 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1a). Based on the calculated electronic structures from previous works 38,41 , the formed PbI 2 /WS 2 heterostructures show a type-I band alignment, such that the photogenerated electrons and holes can be transferred from the PbI 2 to the WS 2 monolayer ( Fig. 1a), which is also confirmed by our experimental results.…”

Section: Pbi 2 /Ws 2 Heterostructures and Near-unity Polarizationsupporting

confidence: 89%

“…The bandgap can be tuned from a direct gap of 2.28 eV to an indirect-gap of 2.63 eV when reducing its thickness or a fine-tuning by applying strain 25,26 . Due to the vdW nature, layered PbI 2 can easily form heterostructures with other TMDCs materials 36 , exhibiting versatile band alignment 37,38 . Furthermore, since PbI 2 can be used as a precursor of lead halide perovskite, the conversion from PbI 2 /TMDCs to perovskite/TMDCs heterostructures have been realized 39,40 , which further extends the applications of PbI 2 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Zhang

Liu

et al. 2020

Nat Commun

Self Cite

View full text Add to dashboard Cite

The generation and manipulation of spin polarization at room temperature are essential for 2D van der Waals (vdW) materials-based spin-photonic and spintronic applications. However, most of the high degree polarization is achieved at cryogenic temperatures, where the spin-valley polarization lifetime is increased. Here, we report on room temperature high-spin polarization in 2D layers by reducing its carrier lifetime via the construction of vdW heterostructures. A near unity degree of polarization is observed in PbI2 layers with the formation of type-I and type-II band aligned vdW heterostructures with monolayer WS2 and WSe2. We demonstrate that the spin polarization is related to the carrier lifetime and can be manipulated by the layer thickness, temperature, and excitation wavelength. We further elucidate the carrier dynamics and measure the polarization lifetime in these heterostructures. Our work provides a promising approach to achieve room temperature high-spin polarizations, which contribute to spin-photonics applications.

show abstract

Section: Pbi 2 /Ws 2 Heterostructures and Near-unity Polarizationsupporting

confidence: 89%

mentioning

confidence: 99%

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Zhang

Liu

et al. 2020

Nat Commun

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is known that both the carrier extraction and non‐radiative recombination could shorten the carrier lifetime in the stack structure, due to spatially separated charges and additional non‐radiative recombination sites being created during the formation of the stack structure. [ 55 ] We studied carrier recombination kinetics at the interfaces of SnO 2 (ETM)/perovskite (with or without NMAI)/spiro‐OMeTAD (HTM) by time‐resolved PL (TRPL) measurement. The film with NMAI treatment showed longer average carrier lifetime (172.05 ns) than that of the control (109.47 ns), indicating a slower recombination rate in the ETM/NMAI‐treated perovskite/HTM stack.…”

Section: Resultsmentioning

confidence: 99%

Efficient Perovskite Solar Cells by Reducing Interface‐Mediated Recombination: a Bulky Amine Approach

Liang

Luo

et al. 2020

Advanced Energy Materials

230

199

View full text Add to dashboard Cite

meantime, the ease of the solution process at low temperature renders this technology up-and-coming for large-scale low-cost manufacture. However, these solution-processed perovskite films are usually polycrystalline, which readily form defects at the grain boundaries and on the surface of the films. [1][2][3][4][5][6] Such defects are the center of non-radiative recombination of photo-generated electrons and holes, which causes shorter carrier lifetime and lower open-circuit voltage (V OC ). Hence, in real devices, higher recombination rate occurs close to the interface of the sequentially deposited layers. For typical n-i-p perovskite solar cells (PSCs), the perovskite/hole transport layer (HTL) interface holds the high defect density, such as cation/anion vacancy and dangling bonds, etc., [7,8] resulting in defect-assisted recombination. Additionally, the energy level mis-alignment near the interface due to quasi-fermi level pinning will increase recombination velocity [9] and the recombination loss occurs inevitably across interfaces between holes in HTL and minority carriers (electron) in the perovskite, or HTL themselves. [10,11] These existing recombination loss channels at the surface/ interface of the perovskite will severely limit the V OC and overall efficiency of PSCs.Many studies have demonstrated that passivation is an efficient method to lessen the non-radiative recombination loss at the surface/interface of the perovskite in n-i-p PSCs. For example, excess PbI 2 [4,[12][13][14] was believed to passivate the grain boundaries and interface of electron transport layer with perovskite; conjugated polymers [15] and insulating poly(methyl methacrylate) [16,17] were also used to passivate the interface of perovskite/HTL. Recently, various ammonium halide compounds, [8,18,19] especially bulky organic ammonium halide salts were adopted to passivate the surface of perovskite, such as 1,8-octanediammonium iodide, [3] adamantylammonium hydroiodide, [7] (fluorine-)phenylethylammonium iodide (F-)PEAI, [20][21][22][23] n-hexyl trimethyl ammonium bromide, [24] etc. They could interact with the undercoordinated ions or form low-dimensional perovskite phases to passivate the surface/ interface of bulk perovskite. The stability of devices was also usually improved due to the suppression of ionic migration by the packed organic moiety or the formation of hydrophobic low-dimensional perovskites. [7,23,25] A very recent work by Jiang et al. found exceptionally that the insulating PEAI salt, rather than the 2D layered PEA 2 PbI 4 perovskite, served as a moreThe presence of non-radiative recombination at the perovskite surface/ interface limits the overall efficiency of perovskite solar cells (PSCs). Surface passivation has been demonstrated as an efficient strategy to suppress such recombination in Si cells. Here, 1-naphthylmethylamine iodide (NMAI) is judiciously selected to passivate the surface of the perovskite film. In contrast to the popular phenylethylammonium iodide, NMAI post-treatment primarily leaves NMAI sal...

show abstract

“…[17] These bands (CB and VB) are primarily responsible for band bending and charge transfer across the heterointerface to the highest-occupied-molecular-orbital/lowest unoccupied molecular orbital (HOMO/LUMO) level of the organic molecule in MoS 2 -organic heterostructures. [3,4,20] In contrast, for TMD hybrid heterostructures with a type-II (staggered) band alignment photoinduced carriers can transfer through the interface and be separated at different material due to the large band offsets. [18,19] Generally, in the case of type-I (normal) band edge alignment, the photogenerated electrons and holes can efficiently transfer from wider bandgap material to the narrower bandgap material, leading to an increased carrier population and enhanced PL emission, which has the potential for light-emitting applications.…”

mentioning

confidence: 99%

MoS₂ and Perylene Derivative Based Type‐II Heterostructure: Bandgap Engineering and Giant Photoluminescence Enhancement

Obaidulla

Habib

Khan

et al. 2019

Adv Materials Inter

View full text Add to dashboard Cite

2D transition metal dichalcogenides (TMDs) are a promising material system for optoelectronic applications. However, their key figure of merit, the room‐temperature photoluminescence (PL), is extremely low. To overcome this challenge, TMDs need interfacing with other semiconducting materials and discover the underlying physical phenomena. Herein, the optical properties and PL mechanisms of molybdenum disulfide‐organic perylene derivative (PDI/MoS2) based type‐II heterostructures, i.e., PTCDA/MoS2 and PTCDI‐Ph/MoS2, are studied experimentally and theoretically. The PL of MoS2 in PTCDA/MoS2 is enhanced, while a dramatic PL quenching of MoS2 is observed on PTCDI‐Ph/MoS2. The significant radiative PL enhancement of PTCDA/MoS2 is primarily due to the bandgap reduction, high exciton/trion ratio, and epitaxial growth of PTCDA. In contrast, “trap‐like” states in heterointerface, relatively low exciton/trion ratio, and less ordered morphology are responsible for PL quenching of PTCDI‐Ph/MoS2 heterostructure. These findings would provoke a new way to engineer the light‐matter interactions in organic/TMD hybrids, which enables light‐emitting, light‐harvesting applications, and neuromorphic devices.

show abstract

Direct Vapor Growth of 2D Vertical Heterostructures with Tunable Band Alignments and Interfacial Charge Transfer Behaviors

Cited by 103 publications

References 52 publications

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Efficient Perovskite Solar Cells by Reducing Interface‐Mediated Recombination: a Bulky Amine Approach

MoS₂ and Perylene Derivative Based Type‐II Heterostructure: Bandgap Engineering and Giant Photoluminescence Enhancement

Contact Info

Product

Resources

About

Direct Vapor Growth of 2D Vertical Heterostructures with Tunable Band Alignments and Interfacial Charge Transfer Behaviors

Cited by 103 publications

References 52 publications

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Room temperature near unity spin polarization in 2D Van der Waals heterostructures

Efficient Perovskite Solar Cells by Reducing Interface‐Mediated Recombination: a Bulky Amine Approach

MoS2 and Perylene Derivative Based Type‐II Heterostructure: Bandgap Engineering and Giant Photoluminescence Enhancement

Contact Info

Product

Resources

About

MoS₂ and Perylene Derivative Based Type‐II Heterostructure: Bandgap Engineering and Giant Photoluminescence Enhancement