Perovskites on Ice: An Additive‐Free Approach to Increase the Shelf‐Life of Triple‐Cation Perovskite Precursor Solutions

O’Kane, Mary E.; Smith, Joel A.; Alanazi, Tarek I.; Cassella, Elena J.; Game, Onkar; Meurs, Sandra van; Lidzey, David G.

doi:10.1002/cssc.202100332

Cited by 16 publications

(23 citation statements)

References 34 publications

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“…There are many differences between these two systems that could result in these different aging processes (this includes solvent blend, molarity and solids composition). Based on what we have found previously, 43 we speculate that deprotonated methylammonium (MA + ) is very unstable in TC solutions. We hereby note that additional molecules in the TC sample (formamidinium, bromine, cesium) could potentially have a stabilizing effect on some of the intermediate complexes formed.…”

Section: Resultssupporting

confidence: 52%

Exploring Nanoscale Structure in Perovskite Precursor Solutions Using Neutron and Light Scattering

et al. 2022

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Tailoring the solution chemistry of metal halide perovskites requires a detailed understanding of precursor aggregation and coordination. In this work, we use various scattering techniques, including dynamic light scattering (DLS), small angle neutron scattering (SANS), and spin–echo SANS (SESANS) to probe the nanostructures from 1 nm to 10 μm within two different lead-halide perovskite solution inks (MAPbI 3 and a triple-cation mixed-halide perovskite). We find that DLS can misrepresent the size distribution of the colloidal dispersion and use SANS/SESANS to confirm that these perovskite solutions are mostly comprised of 1–2 nm-sized particles. We further conclude that if there are larger colloids present, their concentration must be <0.005% of the total dispersion volume. With SANS, we apply a simple fitting model for two component microemulsions (Teubner–Strey), demonstrating this as a potential method to investigate the structure, chemical composition, and colloidal stability of perovskite solutions, and we here show that MAPbI 3 solutions age more drastically than triple cation solutions.

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Section: Resultssupporting

confidence: 52%

Exploring Nanoscale Structure in Perovskite Precursor Solutions Using Neutron and Light Scattering

et al. 2022

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“…We have previously demonstrated that storing precursor inks at low‐temperature can extend their shelf life, however solvent choice is known to have a significant impact on solution stability. [ 69 ] We therefore investigated the shelf‐life of the 1:9 THF:2‐ME MAPbI 3 precursor ink when stored at low temperature (≈4 °C). To do this, devices were periodically fabricated from a single batch of a fridge‐stored ink.…”

Section: Resultsmentioning

confidence: 99%

Binary Solvent System Used to Fabricate Fully Annealing‐Free Perovskite Solar Cells

Cassella

Spooner

Smith

et al. 2023

Advanced Energy Materials

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Organic-inorganic metal halide perovskites are rapidly approaching state-of-the-art silicon solar cells, with bestperforming devices now reaching power conversion efficiencies (PCEs) of 25.7%. [1] Although stability remains a challenge for perovskite solar cells (PSCs), their solution-processability represents a major advantage. Techniques such as blade coating, [2] slot-die coating, [3] and spray coating [4] are compatible with roll-to-roll (R2R) processing, which-in principleshould allow much higher throughput speeds than existing silicon solar technologies. However, the lengthy annealing times used to crystallize the perovskite active layer reduce the maximum theoretical web speeds that could be achieved in a practical manufacture process.In 2020, Rolston et al. demonstrated the highest coating speeds of any scalable PSC processing technologies, achieving production speeds of >12 m min −1 . [5] Spray coating was combined with an atmospheric plasma postprocessing route, [6] creating PSC devices and modules with a PCE of 18% and 15.5%, respectively. Critically, these were fabricated without annealing the perovskite layer. At these speeds, the module cost is expected to be fully competitive with Si. [7] In contrast, the calculated throughput rate for spin-coated PSCs incorporating a 10-min anneal is just 0.017 m min −1 ; a rate prohibitive for commercialization. Furthermore, high temperature processing steps increase device manufacturing costs through increased utility costs and reduced throughput. [8] High process temperatures are also incompatible with many sensitive flexible (polymeric) substrates that are expected to be important in "Internet of Things" applications. [9,10] This growing market is expected to reduce the initial investment and barrier to market entry for perovskites by an order of magnitude. [11] Many approaches to create "annealing-free" PSCs have been demonstrated. For example, thermal evaporation of the perovskite layer without any post-annealing treatments can be used to realize devices having reasonable PCEs of up to 15.7%. [12,13] Zhou et al. demonstrated devices with a PCE of 15.7% for MAPbI 3 (where MA is methylammonium) films grown via electrochemical fabrication. [14] The use of antisolvent High temperature post-deposition annealing of hybrid lead halide perovskite thin films-typically lasting at least 10 min-dramatically limits the maximum roll-to-roll coating speed, which determines solar module manufacturing costs. While several approaches for "annealing-free" perovskite solar cells (PSCs) have been demonstrated, many are of limited feasibility for scalable fabrication. Here, this work has solvent-engineered a high vapor pressure solvent mixture of 2-methoxy ethanol and tetrahydrofuran to deposit highly crystalline perovskite thin-films at room temperature using gas-quenching to remove the volatile solvents. Using this approach, this work demonstrates p-i-n devices with an annealing-free MAPbI 3 perovskite layer achieving stabilized power conversion efficiencies (PCEs) of up to 1...

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“…It is notable that the doublet peaks at δ 2.512 ppm and δ 2.522 ppm are only observed in the aged precursor solution (80 h) without appearing in the fresh precursor solution, 34 which implies that the dimethylammonium (DMA) is slowly formed during the aging process. The formation mechanisms of MFA, DMFA, and DMA in the perovskite precursor solution are accordingly addressed in Scheme 1, where iodide, MA and/or formamidinium (FA) eventually act as reactants to produce either MFA, DMFA, or DMA 35–37 …”

Section: Resultsmentioning

confidence: 99%

“…The formation mechanisms of MFA, DMFA, and DMA in the perovskite precursor solution are accordingly addressed in Scheme 1, where iodide, MA and/or formamidinium (FA) eventually act as reactants to produce either MFA, DMFA, or DMA. [35][36][37] FTIR spectra were measured to understand the aging effect in the precursor solution. In Figure 2a the observed peaks at 1542.022 cm À1 and 1711.751 cm À1 correspond to COO À antisymmetric stretch (COO À as ) and C O stretch vibration, respectively, [38][39][40][41] being ascribed to the carboxylate of propionate in MAP.…”

Section: Resultsmentioning

confidence: 99%

Importance of precursor complexation for green solvent‐processed perovskite crystals

Kim

2022

Bulletin Korean Chem Soc

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Perovskite solar cells have received great attention as one of the most promising photovoltaics for commercialization. While tremendous efforts have been made to ensure long-term stability, green solvent for perovskite solution process have been enormously explored because of an increasing importance of the safety and environmental issues for market entry. Methylammonium propionate (MAP), being an ionic liquid, has been considered as a suitable nonhazardous and green solvent to replace conventional toxic solvents such as dimethylformamide and dimethyl sulfoxide. In this study, the aging effect of perovskite precursor solution based on MAP is investigated, where the formation of dimethylammonium (DMA) during the precursor aging plays a key role in the perovskite growth. A complexation of MAP, PbI 6 , and DMA is expected to promote the crystal growth toward photo-active black phase, leading to a superior absorbance of the resultant film compared to that from the asprepared precursor solution without aging.

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Perovskites on Ice: An Additive‐Free Approach to Increase the Shelf‐Life of Triple‐Cation Perovskite Precursor Solutions

Cited by 16 publications

References 34 publications

Exploring Nanoscale Structure in Perovskite Precursor Solutions Using Neutron and Light Scattering

Exploring Nanoscale Structure in Perovskite Precursor Solutions Using Neutron and Light Scattering

Binary Solvent System Used to Fabricate Fully Annealing‐Free Perovskite Solar Cells

Importance of precursor complexation for green solvent‐processed perovskite crystals

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