| 1. |
- Alharbi, Essa A., et al.
(författare)
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Formation of High-Performance Multi-Cation Halide Perovskites Photovoltaics by delta-CsPbI3/delta-RbPbI3 Seed-Assisted Heterogeneous Nucleation
- 2021
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Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6832 .- 1614-6840. ; 11:16
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Tidskriftsartikel (refereegranskat)abstract
- The performance of perovskite solar cells is highly dependent on the fabrication method; thus, controlling the growth mechanism of perovskite crystals is a promising way towards increasing their efficiency and stability. Herein, a multi-cation halide composition of perovskite solar cells is engineered via the two-step sequential deposition method. Strikingly, it is found that adding mixtures of 1D polymorphs of orthorhombic delta-RbPbI3 and delta-CsPbI3 to the PbI2 precursor solution induces the formation of porous mesostructured hexagonal films. This porosity greatly facilitates the heterogeneous nucleation and the penetration of FA (formamidinium)/MA (methylammonium) cations within the PbI2 film. Thus, the subsequent conversion of PbI2 into the desired multication cubic alpha-structure by exposing it to a solution of formamidinium methylammonium halides is greatly enhanced. During the conversion step, the delta-CsPbI3 also is fully integrated into the 3D mixed cation perovskite lattice, which exhibits high crystallinity and superior optoelectronic properties. The champion device shows a power conversion efficiency (PCE) over 22%. Furthermore, these devices exhibit enhanced operational stability, with the best device retaining more than 90% of its initial value of PCE under 1 Sun illumination with maximum power point tracking for 400 h.
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| 2. |
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| 3. |
- Hieulle, Jeremy, et al.
(författare)
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Understanding and decoupling the role of wavelength and defects in light-induced degradation of metal-halide perovskites
- 2024
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 17:1, s. 284-295
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Tidskriftsartikel (refereegranskat)abstract
- Light-induced degradation in metal halide perovskites is a major concern that can potentially hamper the commercialization of perovskite optoelectronic devices. The phenomena viz. ion migration, phase segregation, and defect intolerance are believed to be the factors behind the degradation. However, a detailed mechanistic understanding of how and why light reduces the long-term stability of perovskites is still lacking. Here, by combining multiscale characterization techniques and computational studies, we uncover the role of white light in the surface degradation of state-of-the-art FAPbI3-rich perovskite absorbers (reaching up to 22% PCE in solar cells). We unravel the degradation kinetics and found that white light triggers the chemical degradation of perovskite into secondary phases with higher work function and metallic I–V characteristics. Furthermore, we demonstrate that perovskite degradation is triggered by a combined mechanism involving both light and the presence of defects. We employ surface passivation to understand the role of defect intolerance in the degradation process. Moreover, by using filtered light we uncover the wavelength dependency of the light-induced perovskite degradation. Based on our findings, we infer some strategies for material engineering and device design that can expedite the path toward stable perovskite optoelectronic devices.
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| 4. |
- Krishna, Anurag, et al.
(författare)
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Facile synthesis of a hole transporting material with a silafluorene core for efficient mesoscopic CH3NH3PbI3 perovskite solar cells
- 2016
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 4:22, s. 8750-8754
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Tidskriftsartikel (refereegranskat)abstract
- A novel electron-rich small-molecule, 4,4'-(5,5-dihexyl-5H-dibenzo[b,d]silole-3,7-diyl)bis(N,N-bis(4-methoxyphenyl)aniline) (S101), containing silafluorene as the core with arylamine side groups, has been synthesized via a short efficient route. When S101 was incorporated into a CH3NH3PbI3 perovskite solar cell as a hole transporting material (HTM), a short circuit photocurrent density (J(sc)) of 18.9 mA cm(-2), an open circuit voltage (V-oc) of 0.92 V, and a fill factor (FF) of 0.65 contributing to an overall power conversion efficiency (PCE) of similar to 11% which is comparable to the PCE obtained using the current state-of-the-art HTM 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) (eta = 12.3%) were obtained. S101 is thus a promising HTM with the potential to replace the expensive spiro-OMeTAD due to its comparable performance and much simpler and less expensive synthesis route.
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| 5. |
- Krishna, Anurag, et al.
(författare)
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Mitigating the Heterointerface Driven Instability in Perovskite Photovoltaics
- 2023
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 8:8, s. 3604-3613
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have thepotential to revolutionizethefield of photovoltaics, though limited stability has impeded commercialexploitation. The soft heterointerface between the perovskite andcharge-transporting layer is one of the major bottlenecks that limitsoperational stability. Here, we present rationally designed molecularmodulators that synergistically improve the stability of the & alpha;-FAPbI(3)-based perovskite solar cells while retaining power conversionefficiency (PCE) of 24.0% with a high open-circuit voltage (V (OC)) of & SIM;1.195 V. The interfacially modifiedphotovoltaic cells exhibit high operational stability, whereby thechampion device retains & SIM;88% of initial performance after 2000h of maximum power point tracking at 40 & DEG;C and 1 sun illumination.The molecular origins of such enhanced stability and device performanceare corroborated by multiscale characterization techniques and modeling,providing insights into the origins of performance and stability enhancements.
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| 6. |
- Krishna, Anurag, et al.
(författare)
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Nanoscale interfacial engineering enables highly stable and efficient perovskite photovoltaics
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:10, s. 5552-5562
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Tidskriftsartikel (refereegranskat)abstract
- We present a facile molecular-level interface engineering strategy to augment the long-term operational and thermal stability of perovskite solar cells (PSCs) by tailoring the interface between the perovskite and hole transporting layer (HTL) with a multifunctional ligand 2,5-thiophenedicarboxylic acid. The solar cells exhibited high operational stability (maximum powering point tracking at one sun illumination) with a stabilized T-S80 (the time over which the device efficiency reduces to 80% after initial burn-in) of approximate to 5950 h at 40 degrees C and a stabilized power conversion efficiency (PCE) over 23%. The origin of high device stability and performance is correlated to the nano/sub-nanoscale molecular level interactions between ligand and perovskite layer, which is further corroborated by comprehensive multiscale characterization. These results provide insights into the modulation of the grain boundaries, local density of states, surface bandgap, and interfacial recombination. Chemical analysis of aged devices showed that molecular passivation suppresses interfacial ion diffusion and inhibits the photoinduced I-2 release that irreversibly degrades the perovskite. The interfacial engineering strategies enabled by multifunctional ligands can expedite the path towards stable PSCs.
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| 7. |
- Lozano, Rafael, et al.
(författare)
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Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
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Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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| 8. |
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| 9. |
- Stanaway, Jeffrey D., et al.
(författare)
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Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: A systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1923-1994
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Tidskriftsartikel (refereegranskat)abstract
- Background The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk-outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk-outcome pairs, and new data on risk exposure levels and risk- outcome associations. Methods We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
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| 10. |
- Zhang, Hong, et al.
(författare)
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A universal co-solvent dilution strategy enables facile and cost-effective fabrication of perovskite photovoltaics
- 2022
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Cost management and toxic waste generation are two key issues that must be addressed before the commercialization of perovskite optoelectronic devices. We report a groundbreaking strategy for eco-friendly and cost-effective fabrication of highly efficient perovskite solar cells. This strategy involves the usage of a high volatility co-solvent, which dilutes perovskite precursors to a lower concentration (<0.5 M) while retaining similar film quality and device performance as a high concentration (>1.4 M) solution. More than 70% of toxic waste and material cost can be reduced. Mechanistic insights reveal ultra-rapid evaporation of the co-solvent together with beneficial alteration of the precursor colloidal chemistry upon dilution with co-solvent, which in-situ studies and theoretical simulations confirm. The co-solvent tuned precursor colloidal properties also contribute to the enhancement of the stability of precursor solution, which extends its processing window thus minimizing the waste. This strategy is universally successful across different perovskite compositions, and scales from small devices to large-scale modules using industrial spin-coating, potentially easing the lab-to-fab translation of perovskite technologies.
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