Improvement of the humidity stability of organic–inorganic perovskite solar cells using ultrathin Al<sub>2</sub>O<sub>3</sub>layers prepared by atomic layer deposition

Dong, Xu; Fang, Xiang; Lv, Minghang; Lin, Bencai; Zhang, Shuai; Ding, Jianning; Yuan, Ningyi

doi:10.1039/c4ta06128d

Cited by 324 publications

(269 citation statements)

References 30 publications

Supporting

Mentioning

258

Contrasting

Unclassified

Order By: Relevance

“…It has been found that adding an ultrathin compact Al 2 O 3 layer on top of the hole transport layer effectively blocks the water without significantly reducing the overall device efficiency, thus improving the overall stability of the system. [69] The perovskite layer also has a tendency to affect the metal contact layers by reaction of mobile I − ions from the perovskite with the metal contacts, leading to drastic changes in the relative energy levels, and thus in the overall solar cell performance. The reaction of iodide with metal electrodes, such as silver, caused an irreversible degradation of the metal contact on the microscale, and thus a failure of the solar cell.…”

Section: Perovskite Solar Cell Heterojunction Interface Characterizationmentioning

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

Section: Perovskite Solar Cell Heterojunction Interface Characterizationmentioning

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

show abstract

“…After exposing to air for 18 h with a relative humidity of 60% at 35 °C , the Al2O3 modified device maintained 48% of its original efficiency, whereas the device without modification kept only 20% of the original efficiency. Very recently, an ultrathin Al2O3 buffer layer was deposited onto the top of spiro-MeOTAD layer by atomic layer deposition (ALD) [17]. The thickness of Al2O3 layer was precisely controlled by controlling the ALD cycles.…”

Section: +mentioning

confidence: 99%

Stability Issues on Perovskite Solar Cells

2015

View full text Add to dashboard Cite

Organo lead halide perovskite materials like methylammonium lead iodide (CH3NH3PbI3) and formamidinium lead iodide (HC(NH2)2PbI3) show superb opto-electronic properties. Based on these perovskite light absorbers, power conversion efficiencies of the perovskite solar cells employing hole transporting layers have increased from 9.7% to 20.1% within just three years. Thus, it is apparent that perovskite solar cell is a promising next generation photovoltaic technology. However, the unstable nature of perovskite was observed when exposing it to continuous illumination, moisture and high temperature, impeding the commercial development in the long run and thus becoming the main issue that needs to be solved urgently. Here, we discuss the factors affecting instability of perovskite and give some perspectives about further enhancement of stability of perovskite solar cell.

show abstract

“…[9] Beside environmental factors such as thermal stress and UV-light irradiation in air, [9][10][11] humidity-induced changes to the perovskite structure have been identified as one of the major degradation pathways which strongly affects device lifetime. [12,13] Degradation upon exposure to moisture has so far only been suppressed by physical encapsulation or through the introduction of organic or inorganic passivation layers [14][15][16] which may place constraints on device performance. Fully understanding the effect of water on perovskite processing and degradation is thus important to formulate new solutions to this challenge.…”

Section: Introductionmentioning

confidence: 99%

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

Improvement of the humidity stability of organic–inorganic perovskite solar cells using ultrathin Al₂O₃layers prepared by atomic layer deposition

Abstract: The high polarity of water molecules inevitably causes the decomposition of perovskites. We retard the degradation by introducing an ultrathin ALD–Al2O3layer, which has almost no negative effect on performance.

Cited by 324 publications

References 30 publications

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

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

Stability Issues on Perovskite Solar Cells

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

Contact Info

Product

Resources

About

Improvement of the humidity stability of organic–inorganic perovskite solar cells using ultrathin Al2O3layers prepared by atomic layer deposition

Abstract: The high polarity of water molecules inevitably causes the decomposition of perovskites. We retard the degradation by introducing an ultrathin ALD–Al2O3layer, which has almost no negative effect on performance.

Cited by 324 publications

References 30 publications

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

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

Stability Issues on Perovskite Solar Cells

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

Contact Info

Product

Resources

About

Improvement of the humidity stability of organic–inorganic perovskite solar cells using ultrathin Al₂O₃layers prepared by atomic layer deposition