GIWAXS: A powerful tool for perovskite photovoltaics
Chenyue Wang 1, Chuantian Zuo 2, Qi Chen 1, †, and Liming Ding 2, †
1MIIT Key Laboratory for Low-dimensional Quantum Structure and Devices, Experimental Center of Advanced Materials, School of Materials
Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
2Center for Excellence in Nanoscience (CAS), Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS), National Center for
Nanoscience and Technology, Beijing 100190, China
Citation: C Y Wang, C T Zuo, Q Chen, and L M Ding, GIWAXS: A powerful tool for perovskite photovoltaics[J]. J. Semicond., 2021,42(6), 060201. doi/10.1088/1674-4926/42/6/060201
The power conversion efficiency (PCE) for perovskite sol-ar cells (PSCs) now reaches 25.2%[1]. However, the perovskite materials have complex compositions and variable phas,calling for suitable characterization techniques to investigate the underlying operation and degradation mec
hanism. Graz-ing-incidence wide-angle X-ray scattering (GIWAXS) plays an important role in studying perovskite materials. GIWAXS data are generally two-dimensional diffractograms containing dif-fraction rings of different crystal planes. Grazing-incidence small-angle X-ray scattering (GISAXS) is similar to GIWAXS,while it has a longer detection distance than that of GIWAXS (Fig. 1(a))[2]. GISAXS enlarges the obrvable spatial range up to 10–100 nm and reduces the measurement nsitivity of crys-tallization, and it is mainly ud to determine the morpho-logy of bulk-heterojunction films in nanoscale [3, 4]. Compared to GISAXS, GIWAXS is more popular in perovskite study. This technique has veral advantages as follows: (1) high signal-to-noi ratio (SNR) and nsitive structural resolution; (2) no-contact and nondestructive probing; (3) abundant structural in-formation; (4) depth resolution; (5) in-situ obrvation. Here,we discuss two applications of GIWAXS, i.e., the crystallograph-ic information at steady state, and the in-situ measurement to probe the temporal information. As an important structur-al parameter of perovskite films, crystallographic orientation affects the optoelectronic properties and materials stability.The 2D GIWAXS diffractogram prents the Debye-Scherrer ring for certain crystallographic plane, enabling characteriza-tion of structural orientation of perovskite films. The orienta-tion degree for crystal planes can be obtained quantitatively according to the diffraction rings along the azimuth by using Herman’s orientation function.
Quasi-2D perovskites receive attention due to their vari-able structures, tunable composition, and relatively high stabil-ity. The insulating organic long-chain cations in quasi-2D per-ovskites can block carrier transport. Suitable crystal orienta-tion can enhance the carrier transport in 2D perovskites, thus improving device performance. GIWAXS measurements give in-formation about crystal orientation, it can also tell the stack-ing manner of grains at different depths, which is esntial for understanding the crystallization mechanism. For ex-ample, by using GIWAXS, Choi et al. found that the nucle-ation and crystallization of BA 2MA 3Pb 4I 13 perovskite occurs at the gas-liquid interface during annealing, which results in the vertical alignment of 2D perovskite crystals (Fig. 1(b))[5]. They further regulated the solvent and cation to prepare highly ver-tically orientated 2D perovskite films [6]. Rafael et al. found that the intermediate solvent complexes provide building blocks in the formation of 2D perovskites according to GI-WAXS measurements [7].
High-quality 3D perovskites tend to make strong orienta-tion at certain azimuth angle. GIWAXS results can be ud to evaluate the crystallization quality of 3D perovskite thin films.The results can also be ud to guide the process optimiza-tion, as well as to clarify the relationship between crystallo-graphic orientation and device performance. Zheng et al. regu-lated the preferenti
al orientation of perovskite crystals and im-proved the interfacial carriers transport in the corresponding devices by substituting A-site alkali metal cations [8].
Recently, residual strain was obrved in perovskite films due to the mismatch of the expansion coefficients for the sub-strate and perovskites, which influences the operational stabil-ity and efficiency of perovskite solar cells. Microscopically, the residual stress within the film results from a biaxial stretch-ing of the perovskite lattice in in-plane direction. The shift of corresponding diffraction peaks at different azimuthal angles reveals the lattice tilting and stretching. By depth-resolved GI-WAXS, Zhu et al. obrved a gradient strain in FA-MA per-ovskite films (Fig. 1(c)). The performance of PSCs was im-proved by reducing lattice mismatch of the crystals [9]. Wang et al. replaced A-site cations on the perovskite surface by us-ing OAI post-treatment, forming a “bone-joint” configuration,reducing surface residual stress and thus improving humid-ity and thermal stability of PSCs [10].
In-situ measurement is attractive in perovskite rearch.It provides a rapid approach to track microstructural changes in perovskite materials, including the crystallization and aging process. It is the key to unravel the kinetics process of perovskite materials. The formation process of perovskite crystals is not fully understood yet. The film formation pro-cess includes
liquid-film gelation stage and crystallization stage. Many studies have shown that the orientation and pha structure of perovskite are already established during gelation stage. The quality of the perovskite precursor film (gel) significantly affects the final perovskite film. In-situ GI-WAXS provides information for the composition evolution during spin-coating process. It also provides guidelines for pre-paration conditions, such as spin speed and time, dripping time of anti-solvent, etc. Amassian et al. have conducted a ries of in-situ GIWAXS studies on perovskite. They ob-
Correspondence to: Q Chen, *********** ; L M Ding, ***************Received 22 MARCH 2021.
RESEARCH HIGHLIGHTS Journal of Semiconductors
(2021) 42, 060201
doi: 10.1088/1674-4926/42/6/060201
pha to sol–gel state, and investigated the effect of precurs-or spin-coating time on PSCs performance [11]. They revealed that Cs + and Rb + cations were able to stabilize the sol–gel state and suppress the pha paration during spin-coating (Fig. 1(d))[12, 13].
GIWAXS can also be ud to study the crystallization pro-cess during thermal annealing. Using the peak area integ-rated by the Debye-Scherrer ring of GIWAXS, all the pha con-tents of perovskites and their evolution during annealing can be deduced, which illustrates the pha transition from inter-mediate pha to perovskite pha. The activation energies for perovskite formation can be determined by using Arrheni-us equation.
Perovskite degradation caud by humidity and heat lim-its the commercialization of PSCs. In conjunction with the mois-ture and temperature controller, the aging process of devices under different conditions can be monitored by GIWAXS.Through depth-resolved characterization, the physical and chemical reactions at different positions can be deduced by combining with other characterizations, which will reveal the degradation mechanisms. Kelly et al. performed systematic in-situ GIWAXS studies on perovskite degradation. They ob-rved that MAPbI 3 films decompod to a hydrated intermedi-ate pha with PbI 64– octahedra in a humid environment [14].To further investigate the performance and structure changes of PSCs under hu
midity, they developed a humidity control-ler in conjunction with I–V measurement system (Fig. 1(e)).The results revealed that the decrea of performance res-ults from the electrode corrosion, rather than perovskite de-composition (Fig. 1(f))[15].
In summary, GIWAXS has been widely ud to reveal the relationship between perovskite crystal structure and device performance. In-situ GIWAXS can be ud to track the crystalliz-ation process and decomposition process of perovskites. This method can help us to develop stable and efficient per-ovskite solar cells.
Acknowledgements
This work was supported by National Natural Science Foundation of China (21975028, 22011540377), Beijing Muni-cipal Science and Technology Project (Z181100005118002),and Beijing Municipal Natural Science Foundation (JQ19008).L. Ding thanks the National Key Rearch and Development Program of China (2017YFA0206600) and the National Natur-
(d)
(f)1.61.20.80.40
0.5Max.
Min.
12111098T i m e (s )
T i m e (s )
q (nm −1)7654
12111098q (nm −1)
7656H
3C
2H
4
300200100
Solvate Disordered colloids
Solvate Disordered colloids
300200100
12111098q (nm −1)
7654
121110+ 5% Cs
98q (nm −1)
765
4
1.0Q xy (Å−1)
1.5
2.0
GIWAXS GISAXS
z x
y k i
q xz
q xy
≈
0.1 m ≈ 2
.0−5.0 m
q z
q
αi
on mp-TiO 2 substrate interface—preferential orientation
Tensile-strain lm
50 nm 200 nm 500 nm
31.69531.68031.66531.650
1.00.80.6N o r m a l i z e d p a r a m e t e r s
0.40.200
0.5 1.0 1.5 2.0 2.5 3.0Time (h)
3.5
4.0 4.5
5.0 5.5
6.0
(110)I sc V oc FF PCE
Carrier gas
Water bubblers
Mass ow controllers
Synchrotron X-ray beam
Sample
chamber
Kapton描写战争的成语
window
Source-measure unit
CCD area detector
0.25
0.50sin 2
φ
0.75
2θ (°)k f
k f
动物园里αf
αf
I−V data
ψ
χ
ios10壁纸ψ
Fig. 1. (Color online) (a) Schematic diagram of GIWAXS and GISAXS. Reproduced with permission [2], Copyright 2017, John Wiley & Sons Inc.(b) Schematic diagram of the formation of vertically orientated 2D perovskite. Reproduced with permission [5], Copyright 2018, Nature Publish-ing Group. (c) Gradient strain at different depths in perovskite layer. Reproduced with permission [9], Copyright 2019, Nature Publishing Group.(d) Time-resolved GIWAXS for precursor films with and without K + during spin-coating. Reproduced with permission [13], Copyright 2019, Elvier Inc. (e) Humidity control t-up. (f) Time-dependence for MAPbI 3 (110) peak area and device performance parameters. (e) and (f), reproduced with permission [15], Copyright 2018, American Chemical Society.
2
Journal of Semiconductors doi: 10.1088/1674-4926/42/6/060201
al Science Foundation of China (51773045, 21772030, 51922032, 21961160720) for financial support. References
Yoo J J, Seo G, Chua M R, et al. Efficient perovskite solar cells via im-proved carrier management. Nature, 2021, 590, 587
[1]
Schlipf J, Müller-Buschbaum P. Structure of organometal halide perovskite films as determined with grazing-incidence X-ray scat-tering methods. Adv Energy Mater, 2017, 7, 1700131
[2]
Rivnay J, Mannsfeld S C B, Miller C E, et al. Quantitative determina-tion of organic miconductor microstructure from the molecu-lar to device scale. Chem Rev, 2012, 112, 5488
[3]
Richter L J, DeLongchamp D M, Amassian A. Morphology develop-ment in solution-procesd functional organic blend films: An in situ viewpoint. Chem Rev, 2017, 117, 6332
[4]
管三
Chen A Z, Shiu M, Ma J H, et al. Origin of vertical orientation in two-dimensional metal halide perovskites and its effect on photo-voltaic performance. Nat Commun, 2018, 9, 1336
[5]
Chen A Z, Shiu M, Deng X, et al. Understanding the formation of vertical orientation in two-dimensional metal halide perovskite thin films. Chem Mater, 2019, 31, 1336
[6]
Quintero-Bermudez R, Gold-Parker A, Proppe A H, et al. Composi-tional and orientational control in metal halide perovskites of re-duced dimensionality. Nat Mater, 2018, 17, 900
[7]
Zheng G, Zhu C, Ma J, et al. Manipulation of facet orientation in hy-brid perovskite polycrystalline films by cation cascade. Nat Com-mun, 2018, 9, 2793
[8]
Zhu C, Niu X, Fu Y, et al. Strain engineering in perovskite solar cells and its impacts on carrier dynamics. Nat Commun, 2019, 10, 815
[9]
Wang H, Zhu C, Liu L, et al. Interfacial residual stress relaxation in perovskite solar cells with improved stability. Adv Mater, 2019, 31, 1904408
[10]
Munir R, Sheikh A D, Abdelsamie M, et al. Hybrid perovskite thin-film photovoltaics: In situ diagnostics and importance of the pre-cursor solvate phas. Adv Mater, 2017, 29, 1604113
[11]
凤阳旅游景点有哪些
Wang K, Tang M C, Dang H X, et al. Kinetic stabilization of the sol–gel state in perovskites enables facile processing of high-effi-ciency solar cells. Adv Mater, 2019, 31, 1808357
[12]
Dang H X, Wang K, Ghami M, et al. Multi-cation synergy sup-press pha gregation in mixed-halide perovskites. Joule, 2019, 3, 1746
[13]
Yang J, Siempelkamp B D, Liu D, et al. Investigation of CH3NH3PbI3 degradation rates and mechanisms in controlled hu-midity environments using in situ techniques. ACS Nano, 2015, 9, 1955
[14]
Fransishyn K M, Kundu S, Kelly T L. Elucidating the failure mechan-isms of perovskite solar cells in humid environments using in situ grazing-incidence wide-angle X-ray scattering. ACS Energy Lett, 2018, 3, 2127
[15]
Chenyue Wang got his BS from University of
Science and Technology Beijing in 2018. Now
he is a MS student at Beijing Institute of Tech-
nology under the supervision of Professor Qi
Chen. His rearch focus on perovskite sol-
ar cells.
Chuantian Zuo received his PhD in 2018 from
游戏方案National Center for Nanoscience and Techno-
logy (CAS) under the supervision of Professor雾的四字成语
Liming Ding. Then he did postdoctoral re-
arch at CSIRO, Australia. Currently, he is an as-
sistant professor in Liming Ding Group. His re-
arch focus on innovative materials and
devices.
Qi Chen holds BS and MS degrees of Tsinghua
University, and received his PhD degree from
University of California, Los Angeles (UCLA). In
2013–2016, he worked as a postdoc at Califor-
nia Nanosystem Institute (CNSI), UCLA. Now
he is a full professor at Beijing Institute of Tech-
nology. His rearch focus on hybrid materi-
als design, processing and applications in opto-
electronics.
Liming Ding got his PhD from University of Sci-
ence and Technology of China (was a joint stu-
dent at Changchun Institute of Applied Chem-
istry, CAS). He started his rearch on OSCs
and PLEDs in Olle Inganäs Lab in 1998. Later
on, he worked at National Center for Polymer
Rearch, Wright-Patterson Air Force Ba and
Argonne National Lab (USA). He joined Kon-
arka as a Senior Scientist in 2008. In 2010, he
joined National Center for Nanoscience and
Technology as a full professor. His rearch fo-
cus on functional materials and devices. He
is RSC Fellow, the nominator for Xplorer Prize,
and the Associate Editors for Science Bulletin
and Journal of Semiconductors.
Journal of Semiconductors doi: 10.1088/1674-4926/42/6/0602013搞笑的自动回复
