The Role of Water in the Reversible Optoelectronic Degradation of Hybrid Perovskites at Low Pressure

Hall, Genevieve N.; Stückelberger, Michael; Nietzold, Tara; Hartman, Jessi; Park, Ji-Sang; Werner, Jérémie; Niesen, Bjoern; Cummings, Marvin; Rose, Volker; Ballif, Christophe; Chan, Maria K. Y.; Fenning, David P.; Bertoni, Mariana I.

doi:10.1021/acs.jpcc.7b06402

Cited by 18 publications

(12 citation statements)

References 34 publications

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“…Conversely, PL reduction under vacuum is suspected to be the consequence of desorption or debonding of passivating H 2 O and O 2 ‐related species, resulting in higher carrier surface recombination velocity and higher density of defect states in hybrid perovskites . The losses under vacuum conditions indicated by PL were recently substantiated by the observation of reversible V oc loss under vacuum attributed to dehydration of MAPbI 3 with subsequent partial rehydration upon return to ambient conditions …”

Section: Tools To Assess Nanoscale Perovskite Chemistry and Its Optoementioning

confidence: 99%

The Relationship between Chemical Flexibility and Nanoscale Charge Collection in Hybrid Halide Perovskites

Luo

Aharon

Stückelberger

et al. 2018

Adv Funct Materials

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Hybrid organometal halide perovskites are known for their excellent optoelectronic functionality as well as their wide-ranging chemical flexibility. The composition of hybrid perovskite devices has trended toward increasing complexity as fine-tuned properties are pursued, including multielement mixing on the constituents A and B and halide sites. However, this tunability presents potential challenges for charge extraction in functional devices. Poor consistency and repeatability between devices may arise due to variations in composition and microstructure. Within a single device, spatial heterogeneity in composition and phase segregation may limit the device from achieving its performance potential. This review details how the nanoscale elemental distribution and charge collection in hybrid perovskite materials evolve as chemical complexity increases, highlighting recent results using nondestructive operando synchrotron-based X-ray nanoprobe techniques. The results reveal a strong link between local chemistry and charge collection that must be controlled to develop robust, high-performance hybrid perovskite materials for optoelectronic devices.applications including solar cells, [1,2] lightemitting diodes, [3] lasers, [4] and photodetectors. [5] The exceptional minority carrier diffusion lengths in these materials [6,7] lead to nearly 100% internal quantum efficiency [8] which results in high charge-carrier collection efficiency and high external luminescence efficiency in electron-photon conversion devices. [9] Particularly in the field of photovoltaics (PV), their extraordinary material properties [10][11][12] have enabled perovskite solar absorbers to achieve large improvements in device performance in the past 8 years. The perovskite crystal structure is shown in Figure 1a, where the A-site is CH 3 NH 3 + (MA, methylammonium), the B-site is Pb 2+ , and the X-site is I − following the general perovskite formula ABX 3. After demonstration of a device with 3.8% power conversion efficiency (PCE) by Miyasaka and co-workers in a dye-sensitized solar cell architecture using CH 3 NH 3 PbI 3 , [13] a breakthrough in perovskite photovoltaics occurred in 2012 when the first allsolid-state hybrid perovskite devices were shown by Kim et al., [14] improving the chemical stability of the perovskite and enabling device performance to exceed beyond 9% using CH 3 NH 3 PbI 3 perovskites. With intense investigation of perovskite material properties from research groups all over the world, including bandgap engineering by halide mixing [15,16] and device optimization using A-site mixing, [9,17] the record PCE of hybrid perovskite solar cells reached 22.7% in 2017 after achieving 22.1% PCE in 2015 [18] using a mixture of formamidinium lead iodide (CH(NH 2 ) 2 PbI 3 ) with 5% loading of methylammonium lead bromide (CH 3 NH 3 PbBr 3 ) chemistry. [19,20] Surpassing 22% PCE by leveraging the chemical flexibility of the perovskite structure brought hybrid perovskite solar cells on par in efficiency with most polycrystalline solar absor...

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Section: Tools To Assess Nanoscale Perovskite Chemistry and Its Optoementioning

confidence: 99%

The Relationship between Chemical Flexibility and Nanoscale Charge Collection in Hybrid Halide Perovskites

Luo

Aharon

Stückelberger

et al. 2018

Adv Funct Materials

Self Cite

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“…[ 52,64 ] The normalized PCEs started to increase from 2 days up to 4 days for M142 and M143, indicating a slow oxidation process of them. The PCEs of M143 began to decrease after 4 days, and there is an increase trend between 7 and 15 days, suggesting a reversible degradation [ 65–67 ] between 4 and 7 days. Nevertheless, such reversible processes did not contribute to long‐term deterioration of the PSC performance.…”

Section: Resultsmentioning

confidence: 99%

Simple Yet Efficient: Arylamine‐Terminated Carbazole Donors for Organic Hole Transporting Materials

Liu

Zhang

et al. 2021

Solar RRL

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The extraordinary electronic and structural properties of carbazole make it an important donor for the molecular design of hole transport materials (HTMs). However, the development of peripheral carbazole donors has lagged behind. Herein, a series of low‐cost arylamine‐substituted carbazole donors are synthesized by a one‐step facile method. The effect of the terminal arylamine on the optoelectronic, thermal stability, hole mobility, and photovoltaic properties of the studied carbazole HTMs is also investigated. The diphenylamine‐ and carbazole‐substituted carbazoles possess the orthogonal–planar conformation, endowing the HTMs (M142 and M143) with excellent electronic properties and morphological properties. Consequently, power conversion efficiencies (PCEs) of 19.60% and 20.05% accompanied with a high photovoltage are achieved for M142‐ and M143‐based doped devices, respectively, outperforming the controlled cells based on nonsubstituted carbazole HTM (M145, PCE = 17.25%). Moreover, the devices based on M143 exhibit good long‐term storage, thermal, and light stability. This work provides a simple strategy for molecular design in developing efficient carbazole donors.

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“…This observation is at variance with a lattice contraction observed under humid conditions in MAPbCl

[ 38 ], where it is proposed that H

O enters as substitutional defect of MA [ 38 ]. On the other hand, MAPbI

has a larger cell than MAPbCl

, due to the larger iodide, and may host interstitial H

O: an indication in this sense is the reversible photoluminescence blue shift of MAPI under increased partial pressure of water, that has been associated to an increases of the Pb-I bond length due to intercalated water [ 73 ].…”

Section: Discussionmentioning

confidence: 99%

Structural Transitions and Stability of FAPbI3 and MAPbI3: The Role of Interstitial Water

et al. 2021

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We studied the influence of water on the structural stability and transformations of MAPI and FAPI by anelastic and dielectric spectroscopies under various temperature and H2O partial pressure protocols. Before discussing the new results in terms of interstitial water in MAPI and FAPI, the literature is briefly reviewed, in search of other studies and evidences on interstitial water in hybrid halide perovskites. In hydrated MAPI, the elastic anomaly between the cubic α and tetragonal β phases may be depressed by more than 50%, demonstrating that there are H2O molecules dispersed in the perovskite lattice in interstitial form, that hinder the long range tilting of the PbI6 octahedra. Instead, in FAPI, interstitial water accelerates in both senses the reconstructive transformations between 3D α and 1D δ phases, which is useful during the crystallization of the α phase. On the other hand, the interstitial H2O molecules increase the effective size of the MA and FA cations to which are bonded, shifting the thermodynamic equilibrium from the compact perovskite structure to the open δ and hydrated phases of loosely bonded chains of PbI6 octahedra. For this reason, when fabricating devices based on hybrid metal-organic halide perovskites, it is important to reduce the content of interstitial water as much as possible before encapsulation.

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The Role of Water in the Reversible Optoelectronic Degradation of Hybrid Perovskites at Low Pressure

Cited by 18 publications

References 34 publications

The Relationship between Chemical Flexibility and Nanoscale Charge Collection in Hybrid Halide Perovskites

The Relationship between Chemical Flexibility and Nanoscale Charge Collection in Hybrid Halide Perovskites

Simple Yet Efficient: Arylamine‐Terminated Carbazole Donors for Organic Hole Transporting Materials

Structural Transitions and Stability of FAPbI3 and MAPbI3: The Role of Interstitial Water

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