Mechanical signatures of degradation of the photovoltaic perovskite CH3NH3PbI3 upon water vapor exposure

Spina, Massimo; Karimi, A.; Andreoni, Wanda; Pignedoli, Carlo A.; Náfrádi, Bálint; Forró, Lászlø; Horváth, Endre

doi:10.1063/1.4978687

Cited by 41 publications

(46 citation statements)

References 37 publications

(32 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We multiplied the strains identified for (220):1, (004):1, (220):2 and (004):2 (C:1, A:1, C:2 and A:2, nIP) by the Young's modulus for MAPbI3 (14 GPa, chosen to be mid-range among reported values) and plotted these stresses in Figure 4. 63,[65][66][67] Because the modulus is nearly directionally isotropic, 67 68,69 was reported to greatly reduce the average residual in-plane stress, as measured via wafer curvature. 14 However, the contributions of individual twin domains to this stress were not elucidated.…”

Section: Determining Volume Fractions Of Ferroelastic Domainsmentioning

confidence: 99%

Ferroelastic Hysteresis in Thin Films of Methylammonium Lead Iodide

et al. 2020

View full text Add to dashboard Cite

Mechanical strain can modify the structural and electronic properties of methylammonium lead iodide MAPbI3. The consequences of ferroelastic hysteresis, which involves the retention of structural memory upon cycles of deformation, are reported for polycrystalline thin films of MAPbI3. Repeatedly bent films were examined using Grazing Incidence Wide-Angle X-ray Scattering (GIWAXS) to quantitatively characterize the strains and proportions of twin domains.Approximate locations for the coercive stress and saturation on the ferroelastic stress-strain curve are identified, and changes to the stress-strain curve with cyclic strain are characterized. Notably, an external stress source, such as thermal stress from the substrate or a roll-to-roll printing setup, must apply at least |50| MPa to modify the proportions of different twins. The presence of specific twin domains is found to correlate to previously-reported strain and defect heterogeneity in MAPbI3 films. Domains from differently-strained twin sets interact with each other. Long-term stability testing reveals that domain walls are highly immobile over extended periods. Nucleation of new domain walls occurs for specific mechanical strains and correlates closely with degradation. These results help to explain the behavior of ion migration, degradation rate, and photoluminescence in thin films under compressive and tensile strain.

show abstract

Section: Determining Volume Fractions Of Ferroelastic Domainsmentioning

confidence: 99%

Ferroelastic Hysteresis in Thin Films of Methylammonium Lead Iodide

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The E values measured by nanoindentation were reported as ranged from ≈9.7 to ≈23 GPa for inorganic–organic hybrid halides, MAPbX 3 (methylammonium lead halides), and FAPbX 3 (formamidinium lead halides), while H was mostly in the range of ≈0.25 to ≈1.0 GPa. [ 6–13 ] For the inorganic halides like cesium lead bromide (CsPbBr 3 ), only an H value of 0.35 GPa was reported as measured by nanoindentation. [ 6 ] The E value for the inorganic halides is available only from the simulation result, for example, as being ≈41.4 GPa for CsPbBr 3 and ≈44.6 GPa for CsGeBr 3 .…”

Section: Introductionmentioning

confidence: 99%

Anisotropic In Situ Strain‐Engineered Halide Perovskites for High Mechanical Flexibility

Kim

Lee

Cho

2020

Adv Funct Materials

View full text Add to dashboard Cite

Even though halide perovskite materials have been increasingly investigated as flexible devices, mechanical properties under flexible environments have rarely been reported on. Herein, a nonconventional deposition technique that can generate extra compressive or tensile stress in representative inorganic CsPbBr3 and hybrid MAPbI3 (methylammonium lead iodide) halide perovskites is proposed for higher mechanical flexibility. As an impressive result of bending fracture evaluation, fracture energy is substantially improved by ≈260% for CsPbBr3 and ≈161% for MAPbI3 with the maximum compressive strain of −1.33%. Origin of the flexibility enhancements by the in situ strain is verified with structural simulation where the anisotropic lattice distortion, that is, contraction in the ab plane and elongation along the c‐axis, is evident with changes in atomic bond lengths and angles in the halide perovskites. Other mechanical properties such as hardness, film strength, and fracture toughness are also discussed with direct comparisons between the inorganic and hybrid halides. Beyond the successful adjustment of this in situ deposition technique, the strain‐dependent mechanical properties are expected to be extensively useful for designing halides‐based flexible devices.

show abstract

“…

toward the optimization of perovskite thin film growth from simple precursors have improved the efficiency and stability of devices to a high quality standard and low cost, placing them on the verge of commercialization. With a Young's modulus around 20 GPa, [7][8][9][10] perovskites are mechanically softer than most other PV materials such as silicon (>160 GPa), [11,12] GaAs (≈85 GPa), [13] CIGS (≈80 GPa), [14,15] and CdTe (≈40 GPa), [16,17] and their structure has been reported to be prone to light-induced, electric-fieldinduced, and temperature-dependent rearrangements. With a Young's modulus around 20 GPa, [7][8][9][10] perovskites are mechanically softer than most other PV materials such as silicon (>160 GPa), [11,12] GaAs (≈85 GPa), [13] CIGS (≈80 GPa), [14,15] and CdTe (≈40 GPa), [16,17] and their structure has been reported to be prone to light-induced, electric-fieldinduced, and temperature-dependent rearrangements.

…”

mentioning

confidence: 99%

“…[1][2][3][4][5][6] Nevertheless, a better understanding of what influences their crystalline structure is needed in order to achieve phase purity, manage defects, and ultimately achieve optimal device performances.The dramatic gain in solar cell device efficiency since 2012 is only one of the features making perovskites stand out among other photovoltaic materials. With a Young's modulus around 20 GPa, [7][8][9][10] perovskites are mechanically softer than most other PV materials such as silicon (>160 GPa), [11,12] GaAs (≈85 GPa), [13] CIGS (≈80 GPa), [14,15] and CdTe (≈40 GPa), [16,17] and their structure has been reported to be prone to light-induced, electric-fieldinduced, and temperature-dependent rearrangements. [18][19][20][21][22][23] The workhorse system studied to date, methylammonium lead iodide (MAPbI 3 ), is in a tetragonal phase (TP) at room temperature, but undergoes a transition to a cubic phase at high temperature (≈330 K) and an orthorhombic phase (OP) at low temperature (≈150 K).…”

mentioning

confidence: 99%

Influence of Grain Size on Phase Transitions in Halide Perovskite Films

Stavrakas

Zelewski

Frohna

et al. 2019

Advanced Energy Materials

View full text Add to dashboard Cite

toward the optimization of perovskite thin film growth from simple precursors have improved the efficiency and stability of devices to a high quality standard and low cost, placing them on the verge of commercialization. [1][2][3][4][5][6] Nevertheless, a better understanding of what influences their crystalline structure is needed in order to achieve phase purity, manage defects, and ultimately achieve optimal device performances.The dramatic gain in solar cell device efficiency since 2012 is only one of the features making perovskites stand out among other photovoltaic materials. With a Young's modulus around 20 GPa, [7][8][9][10] perovskites are mechanically softer than most other PV materials such as silicon (>160 GPa), [11,12] GaAs (≈85 GPa), [13] CIGS (≈80 GPa), [14,15] and CdTe (≈40 GPa), [16,17] and their structure has been reported to be prone to light-induced, electric-fieldinduced, and temperature-dependent rearrangements. [18][19][20][21][22][23] The workhorse system studied to date, methylammonium lead iodide (MAPbI 3 ), is in a tetragonal phase (TP) at room temperature, but undergoes a transition to a cubic phase at high temperature (≈330 K) and an orthorhombic phase (OP) at low temperature (≈150 K). Recently, we and others [24][25][26] have reported that the structural rearrangement from TP to OP causes a distinct hysteretic change in optical and transport properties as well as device behavior between heating and cooling cycles. This hysteresis could be reduced by scraping the film from the substrate and instead measuring randomly oriented powder samples. [24] These results provide hints that the thermal stability [27] and phase transition can be influenced by the local environment of the film due to interactions between the material and substrate as well as within the bulk film itself. Unless understood and mitigated, such hysteretic changes at low temperature may limit the use of perovskite solar cells in some specific applications, for example, aerospace applications, which require operation at extremely low temperatures [28] (<200 K).State-of-the-art perovskite films are polycrystalline, which leads to microscale inhomogeneities in a number of properties such as morphology and defect distributions [29][30][31][32] and, in turn, to local variations in the electronic environment for charge carriers. Generally, increasing grain sizes in MAPbI 3 films has resulted in improvements in critical performance parameters, such as an increase in carrier mobility and charge collection efficiency, [33,34] along with smaller bandgaps, longer lifetimes, Grain size in polycrystalline halide perovskite films is known to have an impact on the optoelectronic properties of the films, but its influence on their soft structural properties and phase transitions is unclear. Here, temperature-dependent X-ray diffraction, absorption, and macro-and microphotoluminescence measurements are used to investigate the tetragonal to orthorhombic phase transition in thin methylammonium lead iodide films with grain sizes ranging fr...

show abstract

Mechanical signatures of degradation of the photovoltaic perovskite CH3NH3PbI3 upon water vapor exposure

Cited by 41 publications

References 37 publications

Ferroelastic Hysteresis in Thin Films of Methylammonium Lead Iodide

Ferroelastic Hysteresis in Thin Films of Methylammonium Lead Iodide

Anisotropic In Situ Strain‐Engineered Halide Perovskites for High Mechanical Flexibility

Influence of Grain Size on Phase Transitions in Halide Perovskite Films

Contact Info

Product

Resources

About