Solar cells based on metal halide perovskites are one of the most promising photovoltaic technologies
. Over the past few years, the long-term operational stability of such devices has been greatly ...improved by tuning the composition of the perovskites
, optimizing the interfaces within the device structures
, and using new encapsulation techniques
. However, further improvements are required in order to deliver a longer-lasting technology. Ion migration in the perovskite active layer-especially under illumination and heat-is arguably the most difficult aspect to mitigate
. Here we incorporate ionic liquids into the perovskite film and thence into positive-intrinsic-negative photovoltaic devices, increasing the device efficiency and markedly improving the long-term device stability. Specifically, we observe a degradation in performance of only around five per cent for the most stable encapsulated device under continuous simulated full-spectrum sunlight for more than 1,800 hours at 70 to 75 degrees Celsius, and estimate that the time required for the device to drop to eighty per cent of its peak performance is about 5,200 hours. Our demonstration of long-term operational, stable solar cells under intense conditions is a key step towards a reliable perovskite photovoltaic technology.
Nanostructured tin (IV) oxide (SnO2) is emerging as an ideal inorganic electron transport layer in n–i–p perovskite devices, due to superior electronic and low‐temperature processing properties. ...However, significant differences in current–voltage performance and hysteresis phenomena arise as a result of the chosen fabrication technique. This indicates enormous scope to optimize the electron transport layer (ETL), however, to date the understanding of the origin of these phenomena is lacking. Reported here is a first comparison of two common SnO2 ETLs with contrasting performance and hysteresis phenomena, with an experimental strategy to combine the beneficial properties in a bilayer ETL architecture. In doing so, this is demonstrated to eliminate room‐temperature hysteresis while simultaneously attaining impressive power conversion efficiency (PCE) greater than 20%. This approach highlights a new way to design custom ETLs using functional thin‐film coatings of nanomaterials with optimized characteristics for stable, efficient, perovskite solar cells.
SnO2 has recently emerged as an attractive n‐type layer for perovskite solar cells, with advantages of high optical transparency, high electron mobility, UV‐stabilized properties as well as low‐temperature processing. Here, a detailed study of structure and morphology of a critical aspect of these devices is reported—the electron transport layer (ETL)—demonstrating improved energy level alignment, reduced hysteresis, and interfacial recombination, which translates to enhanced device performance and stability.
Organic–inorganic halide perovskite solar cells have rapidly evolved over the last 3 years. There are still a number of issues and open questions related to the perovskite material, such as the ...phenomenon of anomalous hysteresis in current–voltage characteristics and long-term stability of the devices. In this work, we focus on the electron selective contact in the perovskite solar cells and physical processes occurring at that heterojunction. We developed efficient devices by replacing the commonly employed TiO2 compact layer with fullerene C60 in a regular n–i–p architecture. Detailed spectroscopic characterization allows us to present further insight into the nature of photocurrent hysteresis and charge extraction limitations arising at the n-type contact in a standard device. Furthermore, we show preliminary stability data of perovskite solar cells under working conditions, suggesting that an n-type organic charge collection layer can increase the long-term performance.
COVID-19 has disproportionately affected racial and ethnic minority groups, and race and ethnicity have been associated with disease severity. However, the association of socioeconomic determinants ...with racial disparities in COVID-19 outcomes remains unclear.
To evaluate the association of race and ethnicity with COVID-19 outcomes and to examine the association between race, ethnicity, COVID-19 outcomes, and socioeconomic determinants.
A systematic search of PubMed, medRxiv, bioRxiv, Embase, and the World Health Organization COVID-19 databases was performed for studies published from January 1, 2020, to January 6, 2021.
Studies that reported data on associations between race and ethnicity and COVID-19 positivity, disease severity, and socioeconomic status were included and screened by 2 independent reviewers. Studies that did not have a satisfactory quality score were excluded. Overall, less than 1% (0.47%) of initially identified studies met selection criteria.
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Associations were assessed using adjusted and unadjusted risk ratios (RRs) and odds ratios (ORs), combined prevalence, and metaregression. Data were pooled using a random-effects model.
The main measures were RRs, ORs, and combined prevalence values.
A total of 4 318 929 patients from 68 studies were included in this meta-analysis. Overall, 370 933 patients (8.6%) were African American, 9082 (0.2%) were American Indian or Alaska Native, 101 793 (2.4%) were Asian American, 851 392 identified as Hispanic/Latino (19.7%), 7417 (0.2%) were Pacific Islander, 1 037 996 (24.0%) were White, and 269 040 (6.2%) identified as multiracial and another race or ethnicity. In age- and sex-adjusted analyses, African American individuals (RR, 3.54; 95% CI, 1.38-9.07; P = .008) and Hispanic individuals (RR, 4.68; 95% CI, 1.28-17.20; P = .02) were the most likely to test positive for COVID-19. Asian American individuals had the highest risk of intensive care unit admission (RR, 1.93; 95% CI, 1.60-2.34, P < .001). The area deprivation index was positively correlated with mortality rates in Asian American and Hispanic individuals (P < .001). Decreased access to clinical care was positively correlated with COVID-19 positivity in Hispanic individuals (P < .001) and African American individuals (P < .001).
In this study, members of racial and ethnic minority groups had higher risks of COVID-19 positivity and disease severity. Furthermore, socioeconomic determinants were strongly associated with COVID-19 outcomes in racial and ethnic minority populations.
The study was to compare the effectiveness of different epidermal growth factor receptor—tyrosine kinase inhibitors (EGFR‐TKIs) in patients with advanced non‐small‐cell lung cancer (NSCLC) and ...received EGFR‐TKIs as first‐line therapy. This retrospective cohort study was conducted using data from real‐world settings. Patients with stage IIIB and IV NSCLC and first received gefitinib, erlotinib, or afatinib between 2011 and 2015 were included. The date of the first claim for EGFR‐TKIs was set as the index date. Study endpoints were all‐cause death and treatment failure that was defined when patients added on or switched to chemotherapy or terminal care. A total of 5,940 patients, including 3,982 (67.0%) receiving gefitinib, 1,207 (20.3%) receiving erlotinib, and 751 (12.7%) receiving afatinib, were eligible for this study. The 1‐year overall survival (OS) rates for gefitinib, erlotinib, and afatinib groups were 74% (95% confidence interval CI: 72–75%), 75% (95% CI: 73–77%), and 80% (95% CI: 77–83%), respectively. Compared to gefitinib, afatinib was associated with a lower risk of all‐cause death (adjusted hazard ratio aHR = 0.82, 95% CI: 0.72–0.93) but not erlotinib (aHR = 0.95, 95% CI: 0.86–1.05). Similar results were also found regarding the effectiveness of treatment. All the three EGFR‐TKIs showed no differences for both outcomes among patients with an Eastern Cooperative Oncology Group Performance Score of 2. The real‐world data exhibited afatinib was more likely to be used for younger patients in a better condition than other EGFR inhibitors, and observed prolonged OS and treatment effectiveness compared to gefitinib after performing a multivariate Cox regression analysis.
What's new?
Patients in clinical trials have to meet specific criteria, but in the real world, doctors treat patients with a wide variety of age, comorbidities, and disease severity. In this paper, the authors sought to clarify criteria for selecting an EGFR‐TKI for lung cancer patients by collecting data from a real‐world patient cohort. They studied 5,940 patients who received either gefitinib, erlotinib, or afatinib between 2011 and 2015. The patients receiving afatinib showed longer survival than those receiving gefitinib. However, it is noted that physicians tend to prescribe afatinib to younger or healthier patients, which may contribute to improved outcomes.
The high transconductance and low noise of graphene-based field-effect transistors based on large-area monolayer graphene produced by chemical vapor deposition are used for label-free electrical ...detection of DNA hybridization. The gate materials, buffer concentration and surface condition of graphene have been optimized to achieve the DNA detection sensitivity as low as 1pM (10−12M), which is more sensitive than the existing report based on few-layer graphene. The graphene films obtained using conventional PMMA-assisted transfer technique exhibits PMMA residues, which degrade the sensing performance of graphene. We have demonstrated that the sensing performance of the graphene samples prepared by gold-transfer is largely enhanced (by 125%).
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► Single-layer graphene FETs show higher sensitivity for DNA detection than few-layer graphene. ► The detection limit of single-layer graphene devices can achieve as low as 1pM (10−12M). ► The sensing performance of graphene FETs prepared by cleaner transfer technique is 125% enhanced.
Large‐area MoS2 atomic layers are synthesized on SiO2 substrates by chemical vapor deposition using MoO3 and S powders as the reactants. Optical, microscopic and electrical measurements suggest that ...the synthetic process leads to the growth of MoS2 monolayer. The TEM images verify that the synthesized MoS2 sheets are highly crystalline.
Abstract
Patients with device detected atrial high-rate episodes (AHRE) have an increased risk of MACE. The R
2
CHA
2
DS
2
-VASc, CHADS
2
, R
2
CHADS
2
and CHA
2
DS
2
-VASc score have been ...investigated for predicting major adverse cardiovascular events (MACE) in different groups of patients. We aimed to evaluate the R
2
CHA
2
DS
2
-VASc score in combination with AHRE ≥ 6 min for predicting MACE in patients with dual-chamber PPM but no prior atrial fibrillation (AF). We retrospectively enrolled 376 consecutive patients undergoing dual-chamber PPM implantation and no prior AF. The primary endpoint was subsequent MACE. For all patients in the cohort, CHADS
2
, R
2
CHADS
2
, CHA
2
DS
2
-VASc, R
2
CHA
2
DS
2
-VASc scores and AHRE ≥ or < 6 min were determined. AHRE was recorded as a heart rate > 175 bpm (Medtronic) or > 200 bpm (Biotronik) lasting ≥ 30 s. Multivariate Cox regression analysis with time-dependent covariates was used to determine the independent predictors of MACE. ROC-AUC analysis was performed for CHADS
2
, R
2
CHADS
2
, CHA
2
DS
2
-VASc, and R
2
CHA
2
DS
2
-VASc scores and then adding AHRE ≥ 6 min to the four scores. The median age was 77 years, and 107 patients (28.5%) developed AHRE ≥ 6 min. After a median follow-up of 32 months, 46 (12.2%) MACE occurred. Multivariate Cox regression analysis showed that R
2
CHA
2
DS
2
-VASc score (HR, 1.485; 95% CI, 1.212–1.818;
p
< 0.001) and AHRE ≥ 6 min (HR, 2.125; 95% CI, 1.162–3.887;
p
= 0.014) were independent predictors for MACE. The optimal R
2
CHA
2
DS
2
-VASc score cutoff value was 4.5 (set at ≥ 5), with the highest Youden index (AUC, 0.770; 95% CI, 0.709–0.831;
p
< 0.001). ROC-AUC analysis of the four risk scores separately combined with AHRE ≥ 6 min all showed better discriminatory power than the four scores alone (All
Z
-statistic
p
< 0.05). In patients with PPM who develop AHRE ≥ 6 min, it is crucial to perform risk assessment with either four scores to further stratify risk for MACE.
A Cu(
ii
)-di(2-methylpyridyl)methylaminocoumarin fluorescence turn-on sensor (Cu-
1b
) is designed to detect phosphate ions with
K
ass
= 1.4 × 10
5
M
−1
in HEPES buffer. Cu-
1b
is applied to probe ...the GlgE-catalyzed maltose-transfer reaction of α-maltose-1-phosphate to α-1,4-glucan with concomitant release of phosphate ions in
Mycobacterium tuberculosis
.
A fluorescence turn-on sensor (Cu-
1b
) is designed for the selective detection of phosphate ions released from the GlgE-catalyzed maltose-transfer reaction.
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