Self-formed grain boundary healing layer for highly efficient CH3NH3PbI3 perovskite solar cells

Son, Dae Yong; Lee, Jin Wook; Choi, Youn Jin; Jang, In Hyuk; Lee, Seonhee; Yoo, Pil J.; Shin, Hyunjung; Ahn, Namyoung; Choi, Man-Young; Kim, Dongho; Park, Nam Gyu

doi:10.1038/nenergy.2016.81

Cited by 962 publications

(554 citation statements)

References 52 publications

Supporting

Mentioning

534

Contrasting

Order By: Relevance

“…Since the same fabrication method is used for all samples, we expect the excess MAI to be also distributed homogeneously between the preformed MAPbI3 crystals, presumably at the grain boundaries as reported by Son et al [35] Previous studies report the detrimental effect of residual PbI2 material at the perovskite/TiO2 interface on the film stability towards humidity. [31] Here, we investigate the influence of moisture on perovskite films with a more homogeneous distribution of the precursor material excess which is more comparable to the absorber layers used in state-of-the-art devices showing high efficiencies.…”

Section: Effect Of the Hydration On The Perovskite Structurementioning

confidence: 69%

“…The corresponding amount of solid MAI or PbI2 was then added to the stoichiometric perovskite solution to yield the MAI-excess and PbI2-excess solutions, respectively. By employing an anti-solvent assisted one-step deposition method similar to the previously reported protocol for state-of-the-art devices, [24,26,35] a comparable distribution of the precursor excess within the perovskite layer can be expected. In short, the perovskite solution is spin-coated onto a substrate, followed by chlorobenzene dripping to induce crystal nucleation.…”

Section: Effect Of the Hydration On The Perovskite Structurementioning

confidence: 96%

See 1 more Smart Citation

The Influence of Water Vapor on the Stability and Processing of Hybrid Perovskite Solar Cells Made from Non‐Stoichiometric Precursor Mixtures

et al. 2016

View full text Add to dashboard Cite

We investigated the influence of moisture on CH3NH3PbI3 perovskite films and solar cells derived from non-stoichiometric precursor mixtures. We followed both the structural changes under controlled air humidity via in-situ X-ray diffraction, and the electronic behavior of devices prepared from these films. A small PbI2 excess in the films improved the stability of the perovskite compared to stoichiometric samples. We assign this to excess PbI2 layers at the perovskite grain boundaries or to the termination of the perovskite crystals with lead and iodine. In contrast, the MAI-excess films composed of smaller perovskite crystals showed increased electronic disorder and reduced device performance due to poor charge collection. Upon exposure to moisture followed by dehydration ("solvent annealing"), these films recrystallized to form larger, highly oriented crystals with fewer electronic defects and a remarkable improvement in photocurrent and photovoltaic efficiency.

show abstract

Section: Effect Of the Hydration On The Perovskite Structurementioning

confidence: 69%

Section: Effect Of the Hydration On The Perovskite Structurementioning

confidence: 96%

The Influence of Water Vapor on the Stability and Processing of Hybrid Perovskite Solar Cells Made from Non‐Stoichiometric Precursor Mixtures

et al. 2016

View full text Add to dashboard Cite

show abstract

“…In most onestep techniques, the precursors of MAI and PbI 2 or PbCl 2 are simply dissolved in DMF or DMSO in a specific ratio, i.e., stoichiometric or with an excess of one of the components, [97][98][99][100][101] and are then spin-coated onto the substrate and annealed at a particular temperature and time to obtain crystalline layers of perovskite (Figure 3d,e). As mentioned before, simple onestep methods often lead to inhomogeneous coverage of the substrates.…”

Section: One-step Depositionmentioning

confidence: 99%

Capturing the Sun: A Review of the Challenges and Perspectives of Perovskite Solar Cells

Petrus

Schlipf

Cheng

et al. 2017

Advanced Energy Materials

317

201

View full text Add to dashboard Cite

following statement: These materials can be processed from solution and yet exhibit optoelectronic materials properties described in classic solid-state physics textbooks. This unprecedented combination has led to photovoltaic devices that can be processed at room temperature and achieve performance levels similar to industry giant polycrystalline silicon, from a starting point of 3.8% in 2009. [1][2][3][4] The first light-emitting electrochemical cells [5] and diodes [6][7][8] have also been introduced recently, leading to tunable light emission spectra and internal quantum efficiencies exceeding 15%.The road towards these achievements has been marked by a constant improvement of perovskite deposition techniques fueled by our increasing understanding of the crystallization processes. The choice of deposition technique, either from solution or vapor, and the composition and order in which precursor species are applied has a great influence on the crystallization kinetics. Here, one can distinguish one-step methods where the perovskite is formed from a precursor mixture dissolved in a common solution, and two-step methods where the inorganic compound is deposited first and transformed to the perovskite phase later by addition of the organic constituents. [9][10][11] Furthermore, many parameters during processing can have an effect on the crystallization mechanism and consequently on film morphology, such as the choice of solvents, concentrations and processing additives that are often not incorporated into the final product. [11][12][13] We discuss this aspect in Section 2, where we focus our attention on the most commonly employed solution-based techniques. Additionally, as for any new technology trying to displace an incumbent technology, higher efficiencies, lower costs, reproducibility, stability, and sustainability are paramount. In particular, reproducibility has been a major challenge in perovskite solar cells from the beginning: small variations in morphology, like crystal size, film roughness, and pinholes can have detrimental effects on photovoltaic performance. [14] On the other hand, current-voltage measurements often showed a hysteresis that is rarely seen in other photovoltaic technologies. [15] These topics are highlighted in Sections 3 and 4. Finally, in Section 5 we discuss the framework for market introduction, such as cost reduction by choosing low-cost charge transport layers, or how the lifetime of perovskite absorbers can be extended by the choice of materials composition.Hybrid metal halide perovskites have become one of the hottest topics in optoelectronic materials research in recent years. Not only have they surpassed everyone's expectations and achieved similar performance as tried and true polycrystalline silicon photovoltaic devices, but they are also finding applications in a variety of different fields, including lighting. The main advantages of hybrid metal halide perovskites are simple processability, compatible with large-scale solution processing such as roll-to-roll printing, a...

show abstract

“…Yin et al also suggested that chlorine and oxygen could spontaneously segregate into the grain boundaries and passivate those defect levels and deactivate the trap state. [53] Another way to minimize the negative impact of the grain boundaries was investigated by Son et al [54] They added excessive amounts of CH 3 NH 3 I to the precursor solution, and noted that at 6 mole-% excess, CH 3 NH 3 I layers formed at the perovskite grain boundaries, which helped suppress non-radiative recombination and formed highly conductive ionic pathways that improved electron and hole extraction at the grain. [54] Conductive AFM (c-AFM) was used to investigate the conductive properties at the grain boundaries through local current-voltage measurements, with Figure 4a,b showing a film without excess CH 3 NH 3 I and one with 6 mole-% excess, respectively.…”

Section: Grain Boundaries Passivation and Ion Migrationmentioning

confidence: 99%

Microstructural Characterisations of Perovskite Solar Cells – From Grains to Interfaces: Techniques, Features, and Challenges

Rothmann

Etheridge

et al. 2017

Advanced Energy Materials

View full text Add to dashboard Cite

group of crystals that all share the same type of crystal structure based on CaTiO 3 , namely ABX 3 , with A cations, such as methylammonium (CH 3 NH 2 + ), formamidinium (CH(NH 2 ) 2 + ), and cesium (Cs + ); B cations such as tin (Sn 2+ ) and lead (Pb 2+ ); and halides, such as iodide (I − ), bromide (Br − ), and chloride (Cl − ), as the X anion. Since the first report of a solar cell using a hybrid organic-inorganic perovskite by Miyasaka et al. in 2009, the solar cells' efficiency has rapidly increased from 3.8% [2] to over 22.1% [3] certified for laboratoryscale devices. This rapid increase is due in part to intense efforts to develop novel device architectures that are energetically favorable for charge generation and extraction, coupled with basic studies detailing the intrinsic properties of the photoactive perovskite materials. [4] However, this record efficiency is still well below the theoretical limit of ≈31% for a singlejunction photovoltaic device. [5] Significant improvements in processing technologies are needed, which in turn require a detailed understanding of microstructures, interface structures, and overall architectures of the solar cell device."Microstructure", the fine structure of a material from the micrometer to the atomic scale, plays an important role in determining the performance of many types of solar cells in use and under development today. In single crystal photoactive materials like silicon, the intragrain defects, such as stacking faults and dislocations, attract significant research interest since these intragrain defects tend to be decorated by impurities, causing higher recombinative losses in these areas. [6] In polycrystalline materials, such as CdTe, grain boundaries have been found to be a limiting factor in solar cell performance due to an enhanced recombination at the grain boundaries. [7] Modification of the grain boundaries by chlorine can assist electron-hole pair separation and positively contribute to carrier collection efficiency. [7,8] Clearly, detailed knowledge of the microstructures in conventional solar cell materials has played a significant role in understanding and improving the underlying processes that govern overall solar cell performance. Further improvements in power conversion efficiency beyond the current record of 22.1%, as well as improved performance stability of perovskite solar cells, are therefore anticipated through in-depth characterization and understanding of their microstructures.Organic-inorganic hybrid perovskite solar cells form a new type of thin film photovoltaic technology, which has achieved extraordinary improvements in power conversion efficiency in a relatively short time. To further improve the efficiency and stability of the perovskite solar cells, it is critical to understand and control the microstructure of both the functional materials and their interfaces. Much effort has already been made to understand the microstructure of perovskite solar cells and its influence on their performance. This has proved particularly cha...

show abstract

Self-formed grain boundary healing layer for highly efficient CH3NH3PbI3 perovskite solar cells

Cited by 962 publications

References 52 publications

The Influence of Water Vapor on the Stability and Processing of Hybrid Perovskite Solar Cells Made from Non‐Stoichiometric Precursor Mixtures

The Influence of Water Vapor on the Stability and Processing of Hybrid Perovskite Solar Cells Made from Non‐Stoichiometric Precursor Mixtures

Capturing the Sun: A Review of the Challenges and Perspectives of Perovskite Solar Cells

Microstructural Characterisations of Perovskite Solar Cells – From Grains to Interfaces: Techniques, Features, and Challenges

Contact Info

Product

Resources

About