In this paper we describe our investigation of the role of investment in information technology (IT) on economic output and productivity in Australia over a period of about four decades. The ...framework used in this paper is the aggregate production function, where IT capital is considered as a separate input of production along with non-IT capital and labour. The empirical results from the study indicate the evidence of robust technical progress in the Australian economy in the 1990s. IT capital had a significant impact on output, labour productivity and technical progress in the 1990s. In recent years, however, the contribution of IT capital on output and labour productivity has slowed down. Regaining the IT capital productivity therefore remains as a key challenge for Australia, especially in the context of greater IT investment in the future.
•IT capital had a significant impact on output and productivity in the 1990s.•Contribution of IT-capital has slowed down in 2000s.•IT capital deepening Granger-causes technical progress and labour productivity.•There is a need to improve IT-capital productivity.
The electron transport layer (ETL) is critical in perovskite solar cells (PSCs) as it controls the optics of the complete solar cell. This study uses an industrially viable RF magnetron sputtering ...technique to prepare the tungsten oxide (WO
x
) ETL for PSCs. Necessary morphological and optoelectronic investigations were carried out to ensure the high-quality WO
x
thin-film. The influence of the deposition power on the ETL thickness and PSC optics were systematically investigated. A three-dimensional (3D) finite-difference time-domain (FDTD) approach analyses the optics and optimization of the complete solar cell. The investigations allow the optimized planar PSC to determine the
J
SC
of > 21 mA/cm
2
. The optical performance of the planar device is limited due to higher optical losses; hence, the current study proposes a PSC design embedded with Ag nanoparticles. The proposed PSC can improve the
J
SC
by ~ 17% (up to 24.5 mA/cm
2
) than the planar device owing to improved light trapping, further boosting the PSC's energy conversion efficiency (ECE). A detailed discussion on film realization and solar cell optics is provided.
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•Ionic liquids (ILs) aided-device engineering champions is widely reviewed.•The role of ILs in the production of high-quality perovskite film is discussed.•ILs can potentially improve ...the long-term stability of perovskite solar cells.•ILs represents a significant step toward reliable perovskite PV technology.
The efficiency of perovskite solar cells (PSCs) is rapidly increasing, so that their long-term operational stability has become a major focus for commercialization and market adoption. The development of novel strategies and materials to improve the stability of small and large solar modules without compromising power conversion efficiency (PCE) is an ongoing challenge. Ionic liquids (ILs) are emerging as useful additives, solvents, and charge transport materials for the preparation of highly efficient perovskite films. Perovskite crystallizes slowly in ILs to form large and uniform grains, and PSCs fabricated with high-quality perovskite films are efficient and stable. Herein we review recently developed systemic device engineering, and we discuss the impact of ILs in the production of highly efficient and stable PSCs. This review is intended to serve as a guide to develop highly crystalline perovskite films with larger grains and more homogeneous morphologies, all of which contribute to enhancing the stability of PSC performance. Recent progress in the use of ILs as solvents and additives for PSCs is a significant step toward developing reliable perovskite photovoltaic devices. Finally, we discuss challenges and future research directions for the fabrication of efficient and stable PSCs.
Abstract
Recyclable titanium dioxide (TiO
2
)-based photocatalytic self-cleaning films (SCFs) having a bilayer structure were prepared and assessed. These SCFs comprised two layers of fibers ...fabricated using an electrospinning process. The self-cleaning layer was made of acrylonitrile–butadiene–styrene (ABS) fibers with embedded TiO
2
while the substrate layer was composed of fibers made by simultaneously electrospinning poly (vinyl alcohol) (PVA) and ABS. This substrate improved the mechanical strength of the SCF and provided greater adhesion due to the presence of the PVA. The experimental results showed that the hydrophobicity (as assessed by the water contact angle), photocatalytic properties and self-cleaning efficiency of the SCF were all enhanced with increasing TiO
2
content in the ABS/TiO
2
fibers. In addition, the introduction of the substrate layer allowed the SCFs to be applied to various surfaces and then peeled off when desired. The ABS fibers effectively improved the strength of the overall film, while deterioration of the ABS upon exposure to UV light was alleviated by the addition of TiO
2
. These SCFs can potentially be recycled after use in various environments, and therefore have applications in the fields of environmental protection and medical science.
In the design of electron-transport layers (ETLs) to enhance the efficiency of planar perovskite solar cells (PSCs), facile electron extraction and transport are important features. Here, we consider ...the effects of different titanium oxide (TiO2) polymorphs, anatase and brookite. We design and fabricate high-phase-purity, single-crystalline, highly conductive, and low-temperature (<180 °C)-processed brookite-based TiO2 heterophase junctions on fluorine-doped tin oxide (FTO) as the substrate. We test and compare single-phase anatase (A) and brookite (B) and heterophase anatase–brookite (AB) and brookite–anatase (BA) as ETLs in PSCs. The power-conversion efficiencies (PCEs) of PSCs with low-temperature-processed single-layer FTO-B as the ETL were as high as 14.92%, which is the highest reported efficiency of FTO-B-based single-layer PSC. This implies that FTO-B serves as an active phase and can be a potential candidate as an n-type ETL scaffold in planar PSCs. Moreover, the surface of highly crystalline brookite TiO2 exhibits a tendency toward interparticle necking, leading to the formation of compact scaffolds. Furthermore, PSCs with heterophase junction FTO-AB ETLs exhibited PCEs as high as 16.82%, which is superior to those of PSCs with single-phase anatase (FTO-A) and brookite (FTO-B) as the ETLs (13.86% and 14.92%, respectively). In addition, the PSCs with FTO-AB exhibited improved efficiency and decreased hysteresis compared with those with FTO-BA (13.45%) due to the suitable band alignment with the perovskite layer, which resulted in superior photogenerated charge-carrier extraction and reduced charge accumulation at the interface between the heterophase junction and perovskite. Thus, the present work presents an effective strategy by which to develop heterophase junction ETLs and manipulate the interfacial energy band to further improve the performance of planar PSCs and enable the clean and eco-friendly fabrication of low-cost mass production.
Highlights
Industrially viable bottom-up spray pyrolysis deposition technique was used to prepare the highly compact TiO
2
film, which is a vital element for the multi-layer front contact.
The ...optimization of the front contact is presented by fabricating reproducible and efficient perovskite solar cells
Multi-layer front contact is applied to realize efficient perovskite single-junction and perovskite/perovskite tandem solar cells, where optics and electrical effects of solar cells are studied by optically coupled 3D electromagnetic simulations.
The photovoltaic performance of perovskite solar cells (PSCs) can be improved by utilizing efficient front contact. However, it has always been a significant challenge for fabricating high-quality, scalable, controllable, and cost-effective front contact. This study proposes a realistic multi-layer front contact design to realize efficient single-junction PSCs and perovskite/perovskite tandem solar cells (TSCs). As a critical part of the front contact, we prepared a highly compact titanium oxide (TiO
2
) film by industrially viable Spray Pyrolysis Deposition (SPD), which acts as a potential electron transport layer (ETL) for the fabrication of PSCs. Optimization and reproducibility of the TiO
2
ETL were discreetly investigated while fabricating a set of planar PSCs. As the front contact has a significant influence on the optoelectronic properties of PSCs, hence, we investigated the optics and electrical effects of PSCs by three-dimensional (3D) finite-difference time-domain (FDTD) and finite element method (FEM) rigorous simulations. The investigation allows us to compare experimental results with the outcome from simulations. Furthermore, an optimized single-junction PSC is designed to enhance the energy conversion efficiency (ECE) by > 30% compared to the planar reference PSC. Finally, the study has been progressed to the realization of all-perovskite TSC that can reach the ECE, exceeding 30%. Detailed guidance for the completion of high-performance PSCs is provided.
This paper investigates the cointegration and causal relationships between Information and Communication Technology (ICT) and economic output in Australia using data for about five decades. The ...framework used in this paper is the single-sector aggregate production function, which is the first comprehensive approach of this kind to include ICT and non-ICT capital and other factors to examine long-run Granger causality. The empirical evidence points to a cointegration relationship between ICT capital and output, and implies that ICT capital Granger causes economic output and multifactor productivity, as does non-ICT capital.
•Cointegration relationship exists between GDP and ICT capital and other factors of production.•Evidence of bidirectional causality between GDP and ICT capital.•ICT makes a significant and positive contribution to economic output in both the short and long run.•ICT capital Granger causes multifactor productivity.
Recent achievements, based on lead (Pb) halide perovskites, have prompted comprehensive research on low-cost photovoltaics, in order to avoid the major challenges that arise in this respect: ...Stability and toxicity. In this study, device modelling of lead (Pb)-free perovskite solar cells has been carried out considering methyl ammonium tin bromide (CH
NH
SnBr
) as perovskite absorber layer. The perovskite structure has been justified theoretically by Goldschmidt tolerance factor and the octahedral factor. Numerical modelling tools were used to investigate the effects of amphoteric defect and interface defect states on the photovoltaic parameters of CH
NH
SnBr
-based perovskite solar cell. The study identifies the density of defect tolerance in the absorber layer, and that both the interfaces are 10
cm
, and 10
cm
, respectively. Furthermore, the simulation evaluates the influences of metal work function, uniform donor density in the electron transport layer and the impact of series resistance on the photovoltaic parameters of proposed n-TiO
/i-CH
NH
SnBr
/p-NiO solar cell. Considering all the optimization parameters, CH
NH
SnBr
-based perovskite solar cell exhibits the highest efficiency of 21.66% with the
of 0.80 V,
of 31.88 mA/cm
and Fill Factor of 84.89%. These results divulge the development of environmentally friendly methyl ammonium tin bromide perovskite solar cell.
We present a method for synthesizing brookite-type titanium dioxide (TiO2) using an emulsion-assisted hydrothermal approach and a water-soluble titanium complex with glycolic acid as a complexing ...agent. In this study, stirred hydrothermal synthesis was used to synthesize water-in-oil emulsions with titanium glycolate complex in the aqueous phase. The resulting brookite-type TiO2 was investigated using Raman spectroscopy for crystal polymorph identification, X-ray Diffraction to identify crystal polymorphs and crystallite size, Transmission Electron Microscope for primary particle size, and crystal shape, and Dynamic Light Scattering for TiO2 secondary particle size in aqueous dispersion. The synthesized brookite-type TiO2 was a needle-like crystal with a width between 20 and 30 nm and a length of more than 70 nm, growing in the b-axis direction at an angle of about 70° from the (120) plane. Furthermore, compared to the conventional synthesis method, the secondary particle size was smaller, and the dispersibility in water was improved. The results show that the brookite-type TiO2 dispersion obtained using the emulsion-assisted hydrothermal method can facilitate the formation of uniform films and can be applied to the electron transport layer of organic perovskite solar cells.
World Health Organization (WHO) suggests that exclusive breastfeeding (EBF) is the best nutrition for the neonate. Still, it remains a big challenge to establish EBF not only in Bangladesh but also ...in any developing countries.
The aim of this study was to determine the level of knowledge and practices on EBF and its relationship between different socioeconomic and demographic factors among mothers having at least one child of aged 6-12 months in the rural area of Rajshahi District, Bangladesh.
A community clinic (CC) based study has been conducted by using semi-structured questionnaire. A total of 513 mothers having at least one child aged 6-12 months from 32 different CC in the rural area of Rajshahi District, Bangladesh during September to December 2015. A composite index, chi-square test, and logistic regression model were utilized in this study.
The prevalence of knowledge and practices on EBF were 34.5% and 27.9% among mothers having at least one child aged 6-12 months. From the analyses, mothers age of ≥21 years were (adjusted odds ratio (AOR) = 13.840, 95% CI: 7.394-25.904; p<0.001) times more likely to have knowledge on EBF and (AOR = 0.084, 95% CI: 0.050-0.143; p<0.05) times less likely to have practices of EBF compared to mother's age ≤20 years. Service holders mothers were (AOR = 9.992, 95% CI: 4.485-22.260, p<0.05) times more likely to have practices than that of house wife. Home delivery mothers was (AOR = 0.208, 95% CI: 0.111-0.389; p<0.05) times less likely to have practices of EBF than that of the hospital delivery mothers. Those mothers monthly family income ≥10,000 Bangladeshi taka (BDT) currency was (AOR = 0.092, 95% CI: 0.050-0.168, p<0.05) times less likely to have practices of EBF compared to their counterparts.
This study was found poor knowledge and practices on EBF. This study suggested that education and EBF related intervention could play an important role to increase good knowledge and practices on EBF among mothers. Malnutrition will be decreased if EBF was widely established in Bangladesh.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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