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01 Nov 07:18

Tuning Film Stresses for Open-Air Processing of Stable Metal Halide Perovskites

by Muneeza Ahmad

ACS Appl Mater Interfaces. 2023 Oct 30. doi: 10.1021/acsami.3c11151. Online ahead of print.

ABSTRACT

Challenges to upscaling metal halide perovskites (MHPs) include mechanical film stresses that accelerate degradation, dominate at the module scale, and can lead to delamination or fracture. In this work, we demonstrate open-air blade coating of single-step coated perovskite as a scalable method to control residual film stress after processing and introduce beneficial compression in the thin film with the use of polymer additives such as gellan gum and corn starch. The optoelectronic properties of MHP films with compression are improved with higher photoluminescence yields. MHP film stability is significantly improved under compression, under humidity, heat, and thermal cycling. By measuring the evolution of film stresses, we demonstrate for the first time that stress relaxation occurs in MHP films with tensile stress that correlates with film degradation. This discovery of a new mechanism underpinning MHP degradation shows that film stress can be used as a parameter to screen MHP devices and modules for quality control before deployment as a design for reliability criterion.

PMID:37903284 | DOI:10.1021/acsami.3c11151

12 Jul 04:47

[ASAP] Manipulation of Charge Delocalization in a Bulk Heterojunction Material Using a Mid-Infrared Push Pulse

by Angela Montanaro, Kyu Hyung Park, Francesca Fassioli, Francesca Giusti, Daniele Fausti, and Gregory D. Scholes

TOC Graphic

The Journal of Physical Chemistry C
DOI: 10.1021/acs.jpcc.3c02938
16 Jun 12:57

Light-responsive and corrosion-resistant gas valve with non-thermal effective liquid-gating positional flow control

by Baiyi Chen

Light: Science & Applications, Published online: 16 June 2021; doi:10.1038/s41377-021-00568-9

A light-responsive and corrosion resistant gas valve with non-thermal effective liquid gating positional flow control under a constant pressure by incorporating dynamic gating liquid with light-responsiveness of solid porous substrate.
16 Jun 10:00

Catalytic reductive desymmetrization of malonic esters

by Pengwei Xu

Nature Chemistry, Published online: 10 June 2021; doi:10.1038/s41557-021-00715-0

The desymmetrization of easily accessible malonic esters represents an attractive approach towards the formation of chiral quaternary stereocentres, but is largely limited to enzymatic hydrolysis. Now, a zinc-catalysed asymmetric hydrosilylation reaction—that works with a broad scope of substrates—has been shown to reduce one of the esters to a primary alcohol with excellent enantiocontrol.
31 Oct 02:17

Photoinduced ion-redistribution in CH3NH3PbI3 perovskite solar cells.

by Yanagida M, Shirai Y, Khadka DB, Miyano K
Related Articles

Photoinduced ion-redistribution in CH3NH3PbI3 perovskite solar cells.

Phys Chem Chem Phys. 2020 Oct 29;:

Authors: Yanagida M, Shirai Y, Khadka DB, Miyano K

Abstract
We use photoinduced absorption spectroscopy (PAS) to study the ionic motion in CH3NH3PbI3 perovskite solar cells, consisting of indium tin oxide (ITO)/NiOx/perovskite/phenyl-C61-butyric-acid-methyl ester (PCBM)/aluminum-doped zinc oxide (AZO)/ITO. We observed a slow (∼50 mHz) spectral blue shift (∼10-4 eV) under modulated 520 nm illumination, which we interpreted in terms of the modulation in the bulk ion density. Numerical simulation shows that the mobile ion moves in and out from the double layers at the perovskite/charge transport layer interfaces in order to recover the bulk charge neutrality tipped off-balance by the photocarriers. The diffusion coefficient of the ion is 10-10 to 10-11 cm2 s-1, when we assume that the characteristic time constant of the ion motion is governed by the diffusion.

PMID: 33118563 [PubMed - as supplied by publisher]

06 Jul 07:22

Challenges and strategies relating to device function layers and their integration toward high-performance inorganic perovskite solar cells.

by Wang H, Li H, Cai W, Zhang P, Cao S, Chen Z, Zang Z
Icon for Royal Society of Chemistry Related Articles

Challenges and strategies relating to device function layers and their integration toward high-performance inorganic perovskite solar cells.

Nanoscale. 2020 Jul 03;:

Authors: Wang H, Li H, Cai W, Zhang P, Cao S, Chen Z, Zang Z

Abstract
Parallel to the flourishing of inorganic-organic hybrid perovskite solar cells (PSCs), the development of inorganic cesium-based metal halide PSCs (CsPbX3) is accelerating, with power conversion efficiency (PCE) values of over 20% being obtained. Although CsPbX3 possesses numerous merits, such as superior thermal stability and great potential for use in tandem solar cells, severe challenges remain, such as its phase instability, trap state density, and absorption range limitations, hindering further performance improvements and commercialization. This review summarizes challenges and strategies relating to each device functional layer and their integration for the purposes of performance improvement and commercialization, utilizing the fundamental configuration of a perovskite photo-absorption layer, electron transport layer (ETL), and hole transport layer (HTL ). In detail, we first analyze comprehensively strategies for designing high-quality CsPbX3 perovskite films, including precursor engineering, element doping, and post-treatment, followed by discussing the precise control of the CsPbX3 film fabrication process. Then, we introduce and analyze the carrier dynamics and interfacial modifications of inorganic ETLs, such as TiO2, SnO2, ZnO, and other typical organic ETLs with p-i-n configuration. The pros and cons of inorganic and organic HTLs are then discussed from the viewpoints of stability and band structure. Subsequently, promising candidates, i.e., HTL-free carbon-electrode-based inorganic CsPbX3 PSCs, that meet the "golden triangle" criteria used by the PSC community are reviewed, followed by discussion of other obstacles, such as hysteresis and large-scale fabrication, that lie on the road toward PSC commercialization. Finally, some perspectives relating to solutions to development bottlenecks are proposed, with the attempt to gain insight into CsPbX3 PSCs and inspire future research prospects.

PMID: 32617550 [PubMed - as supplied by publisher]

07 Dec 09:09

[ASAP] Redox-Mediated, Transient Supramolecular Charge-Transfer Gel and Ink

by Shikha Dhiman, Krishnendu Jalani, and Subi J. George*

TOC Graphic

ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b17481
30 Apr 04:48

Doped, Defect-Enriched Carbon Nanotubes as an Efficient Oxygen Reduction Catalyst for Anion Exchange Membrane Fuel Cells

by Chuyen Van Pham, Benjamin Britton, Thomas Böhm, Steven Holdcroft, Simon Thiele

Abstract

Bond polarization of doped atoms and carbon and lattice defects are considered important aspects in the catalytic mechanisms of oxygen reduction reaction (ORR) on heteroatom-doped carbon catalysts. Previous work on metal-free catalysts has focused either on bond polarization or lattice defects. Here multi-heteroatom doped defect-enriched carbon nanotubes (MH-DCNTs) that combine both effects to enhance ORR activity are designed. Lattice defects in MH-DCNTs are enriched by unzipping and length-shortening of carbon nanotubes, and also by creating carbon vacancies via decomposition of doped F atoms. Electrochemical analysis using rotating disc electrode voltammetry shows that the ORR kinetic current density of MH-DCNT increases with lattice-defect density, the latter of which is verified by Raman spectroscopy, while the onset potential increases with annealing temperatures. An optimized MH-DCNT ORR catalyst exhibits a half-wave potential of 0.81 V versus reversible hydrogen electrode and limiting current density of 5.0 mA cm−2 at an electrode rotation speed of 1600 rpm in 0.1 m KOH. Further, it is demonstrated that MH-DCNT, as a cathode catalyst layer in an anion exchange membrane fuel cell (AEMFC), delivers a peak power density of 250 mW cm−2, which is ≈70% the performance of an AEMFC using a conventional Pt/C catalyst.

Thumbnail image of graphical abstract

Multi-heteroatom doped, defect-enriched carbon nanotubes (MH-DCNTs) are designed to combine two catalytic mechanisms: bond polarization and lattice defects for enhanced oxygen reduction reaction (ORR) activity. ORR kinetic current of MH-DCNT correlates with lattice-defect density, while onset potential increases with synthesis temperatures. Optimized MH-DCNTs exhibit comparable ORR performances with Pt-catalyst in both half-cells and full anion exchange membrane fuel cells.

24 Oct 06:56

Highly Periodic Metal Dichalcogenide Nanostructures with Complex Shapes, High Resolution, and High Aspect Ratios

by Sungwoo Jang, Seon Joon Kim, Hyeong-Jun Koh, Doo Hyung Jang, Soo-Yeon Cho, Hee-Tae Jung

Abstract

The development of high resolution, high aspect ratio metal dichalcogenide nanostructures is one of the most important issues in 2D material researchers due to the potential to exploit their properties into high performance devices. In this study, for the first time a way of fabricating metal dichalcogenide nanostructures with high resolution (<50 nm scale) and high aspect ratios (>120) by chemical vapor deposition assisted secondary sputtering phenomenon is reported. This approach can universally synthesize various types of metal dichalcogenides including MoS2, WS2, and SnS2, implying the possibility for further utilization with selenides and tellurides. Also, this method can produce highly periodic complex patterns such as hole–cylinder, concentric rings, and line patterns, which are unprecedented in previous reports. The feature size and aspect ratio of the metal dichalcogenide structures can be manipulated by controlling the dimensions of the photoresist prepatterns, while the pattern resolution and layer orientation can be manipulated by controlling the thickness of the deposited metal film. It is demonstrated that nanostructures with high resolution and high aspect ratio significantly improve gas-sensing properties compared with previous metal dichalcogenide films. It is believed that the method can be a foundation for synthesizing various materials with complex patterns for future applications.

Thumbnail image of graphical abstract

A universal way for fabricating periodic metal dichalcogenide nanostructures with high resolution (<50 nm), high aspect ratio (>120), and complex shapes is developed for the first time. Various metal dichalcogenides are demonstrated in this work, and nanostructures of MoS2, WS2, and SnS2 with serpentine, line, hole–cylinder, and concentric patterns are fabricated over a large area.

29 Dec 14:34

Mechanism of enhancing visible-light photocatalytic activity of BiVO4 via hybridization of graphene based on a first-principles study

RSC Adv., 2016, Accepted Manuscript
DOI: 10.1039/C6RA25721F, Paper
Open Access Open Access
Yuxuan Chen, Xinguo Ma, Di Li, Huihu Wang, Chuyun Huang
The interface properties of the hybrid graphene/BiVO4(001) heterojunction were investigated by first-principle calculations incorporating semiempirical dispersion-correction schemes to describe correctly van der Waals interactions. The results indicate that graphene and...
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