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1.
Nat Commun ; 15(1): 2579, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38519495

ABSTRACT

Perovskite photovoltaics, typically based on a solution-processed perovskite layer with a film thickness of a few hundred nanometres, have emerged as a leading thin-film photovoltaic technology. Nevertheless, many critical issues pose challenges to its commercialization progress, including industrial compatibility, stability, scalability and reliability. A thicker perovskite film on a scale of micrometres could mitigate these issues. However, the efficiencies of thick-film perovskite cells lag behind those with nanometre film thickness. With the mechanism remaining elusive, the community has long been under the impression that the limiting factor lies in the short carrier lifetime as a result of defects. Here, by constructing a perovskite system with extraordinarily long carrier lifetime, we rule out the restrictions of carrier lifetime on the device performance. Through this, we unveil the critical role of the ignored lattice strain in thick films. Our results provide insights into the factors limiting the performance of thick-film perovskite devices.

2.
J Prosthodont ; 33(1): 46-53, 2024 Jan.
Article in English | MEDLINE | ID: mdl-36639956

ABSTRACT

PURPOSE: To study the effect of implant angulation on 3D linear and absolute angular distortions of implant analogs in printed resin models and conventional stone casts. MATERIALS AND METHODS: Three sectional master models with two implants with total inter-implant angulations of 0°, 10°, and 20° were fabricated. For each master model, five conventional stone casts (CS) and printed resin models (PM) were fabricated (n = 5). Test models were made with nonsplinted impression copings and open tray polyether impressions for the CS groups and scan bodies scanned using an intraoral scanner for the PM groups. The physical positions of the implants and implant analogs were measured with a coordinate measuring machine. 3D linear distortion (ΔR) and absolute angular distortion (Absdθ) defined the 3D positional accuracy of the analogs in the test models. Univariate ANOVA was used to analyze data followed by post hoc tests (Tukey HSD, α = 0.05). RESULTS: Mean ΔR was significantly greater for PM10 (73.5 ± 8.9 µm) and PM20 (65.5 ± 33.3 µm) compared to CS0 (16.8 ± 14.1 µm), CS10 (22.2 ± 13.0 µm), CS20 (15.6 ± 19.9 µm), and PM0 (23.9 ± 16.1 µm). For Absdθ, there were no significant differences between test groups. CONCLUSIONS: With conventional stone casts, implant angulation had no significant effect on 3D linear and absolute angular distortions. Amongst printed resin models test groups, angulated implants had significantly greater ΔR. Amongst angulated implants test groups, printed resin models had significantly greater ΔR than conventional stone casts. Compared to the master model, all test groups, regardless of inter-implant angulation, produced greater inter-analog distances.


Subject(s)
Dental Implants , Dental Impression Materials , Dental Impression Technique , Models, Dental
3.
Adv Mater ; 36(14): e2307265, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38126918

ABSTRACT

Metal halide perovskite solar cells (PSCs) are infamous for their batch-to-batch and lab-to-lab irreproducibility in terms of stability and performance. Reproducible fabrication of PSCs is a critical requirement for market viability and practical commercialization. PSC irreproducibility plagues all levels of the community; from institutional research laboratories, start-up companies, to large established corporations. In this work, the critical function of atmospheric humidity to regulate the crystallization and stabilization of formamidinium lead triiodide (FAPbI3) perovskites is unraveled. It is demonstrated that the humidity content during processing induces profound variations in perovskite stoichiometry, thermodynamic stability, and optoelectronic quality. Almost counterintuitively, it is shown that the presence of humidity is perhaps indispensable to reproduce phase-stable and efficient FAPbI3-based PSCs.

4.
Article in English | MEDLINE | ID: mdl-37923367

ABSTRACT

In this study, we synthesized a series of four large-band gap small molecule acceptors with side-chain engineering of the dithieno-pyrrolo-fused pentacyclic benzotriazole (BZTTP or Y1 core) or the fused-ring dithienothiophene-pyrrolobenzothiadiazole (TPBT or Y6 core) with difluoro-indene-dione (IO2F) or dichloro-indene-dione (IO2Cl) end groups to form Y1-IO2F, Y1-IO2Cl, Y6-IO2F, and Y6-IO2Cl acceptors, respectively, for blending with poly(3-hexyl thiophene) (P3HT) for bulk heterojunction organic photovoltaics. The complementary UV-vis absorption spectra of these small molecules and P3HT along with their offset energy bands allow broad absorption and effective electron transfer. Through synchrotron wide-angle X-ray scattering (WAXS) analyses and contact angle measurements, we found that the blend of the small molecule Y6-IO2F (having a TPBT core) and P3HT achieves an optimum morphology that balances their crystallinity and miscibility, among those of these four blends, leading to a substantial enhancement in the short-circuit current density and thus power conversion efficiency (PCE) in their devices. For example, the P3HT:Y6-IO2F (w/w: 1/1.2) device exhibited a champion PCE of 10.5% with a short current density (Jsc) value of 15.9 mA/cm2 as compared to the P3HT:Y1-IO2F device having a PCE of 2.2% with a Jsc value of 5.7 mA/cm2 because of the higher Y6-IO2F (with TPBT core) molecular packing that facilitated carrier transport in the devices. The enhanced thermal stability exhibited by the devices incorporating Y6-IO2F and Y6-IO2Cl, as compared to that of Y1-IO2F and Y1-IO2Cl devices, is also due to the more planar TPBT core structure, while the photostability of devices incorporating Y6-IO2Cl and Y1-IO2Cl is better than that of devices incorporating Y6-IO2F and Y1-IO2F, owing to more photostable chemical structures. These results present an outstanding performance for P3HT-based organic solar cells. Moreover, these small molecule blends are processed with an environmentally friendly solvent tetrahydrofuran, demonstrating both the sustainability and commercial viability of these types of organic photovoltaics.

5.
Adv Mater ; 35(45): e2304168, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37463679

ABSTRACT

Chemical bath deposition (CBD) is widely used to deposit tin oxide (SnOx ) as an electron-transport layer in perovskite solar cells (PSCs). The conventional recipe uses thioglycolic acid (TGA) to facilitate attachments of SnOx particles onto the substrate. However, nonvolatile TGA is reported to harm the operational stability of PSCs. In this work, a volatile oxalic acid (OA) is introduced as an alternative to TGA. OA, a dicarboxylic acid, functions as a chemical linker for the nucleation and attachment of particles to the substrate in the chemical bath. Moreover, OA can be readily removed through thermal annealing followed by a mild H2 O2 treatment, as shown by FTIR measurements. Synergistically, the mild H2 O2 treatment selectively oxidizes the surface of the SnOx layer, minimizing nonradiative interface carrier recombination. EELS (electron-energy-loss spectroscopy) confirms that the SnOx surface is dominated by Sn4+ , while the bulk is a mixture of Sn2+ and Sn4+ . This rational design of a CBD SnOx layer leads to devices with T85 ≈1500 h, a significant improvement over the TGA-based device with T80 ≈250 h. The champion device reached a power conversion efficiency of 24.6%. This work offers a rationale for optimizing the complex parameter space of CBD SnOx to achieve efficient and stable PSCs.

6.
Nature ; 620(7973): 323-327, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37344595

ABSTRACT

The black phase of formamidinium lead iodide (FAPbI3) perovskite shows huge promise as an efficient photovoltaic, but it is not favoured energetically at room temperature, meaning that the undesirable yellow phases are always present alongside it during crystallization1-4. This problem has made it difficult to formulate the fast crystallization process of perovskite and develop guidelines governing the formation of black-phase FAPbI3 (refs. 5,6). Here we use in situ monitoring of the perovskite crystallization process to report an oriented nucleation mechanism that can help to avoid the presence of undesirable phases and improve the performance of photovoltaic devices in different film-processing scenarios. The resulting device has a demonstrated power-conversion efficiency of 25.4% (certified 25.0%) and the module, which has an area of 27.83 cm2, has achieved an impressive certified aperture efficiency of 21.4%.

7.
Front Public Health ; 11: 1063466, 2023.
Article in English | MEDLINE | ID: mdl-36860378

ABSTRACT

Purpose: The COVID-19 pandemic has drastically disrupted global healthcare systems. With the higher demand for healthcare and misinformation related to COVID-19, there is a need to explore alternative models to improve communication. Artificial Intelligence (AI) and Natural Language Processing (NLP) have emerged as promising solutions to improve healthcare delivery. Chatbots could fill a pivotal role in the dissemination and easy accessibility of accurate information in a pandemic. In this study, we developed a multi-lingual NLP-based AI chatbot, DR-COVID, which responds accurately to open-ended, COVID-19 related questions. This was used to facilitate pandemic education and healthcare delivery. Methods: First, we developed DR-COVID with an ensemble NLP model on the Telegram platform (https://t.me/drcovid_nlp_chatbot). Second, we evaluated various performance metrics. Third, we evaluated multi-lingual text-to-text translation to Chinese, Malay, Tamil, Filipino, Thai, Japanese, French, Spanish, and Portuguese. We utilized 2,728 training questions and 821 test questions in English. Primary outcome measurements were (A) overall and top 3 accuracies; (B) Area Under the Curve (AUC), precision, recall, and F1 score. Overall accuracy referred to a correct response for the top answer, whereas top 3 accuracy referred to an appropriate response for any one answer amongst the top 3 answers. AUC and its relevant matrices were obtained from the Receiver Operation Characteristics (ROC) curve. Secondary outcomes were (A) multi-lingual accuracy; (B) comparison to enterprise-grade chatbot systems. The sharing of training and testing datasets on an open-source platform will also contribute to existing data. Results: Our NLP model, utilizing the ensemble architecture, achieved overall and top 3 accuracies of 0.838 [95% confidence interval (CI): 0.826-0.851] and 0.922 [95% CI: 0.913-0.932] respectively. For overall and top 3 results, AUC scores of 0.917 [95% CI: 0.911-0.925] and 0.960 [95% CI: 0.955-0.964] were achieved respectively. We achieved multi-linguicism with nine non-English languages, with Portuguese performing the best overall at 0.900. Lastly, DR-COVID generated answers more accurately and quickly than other chatbots, within 1.12-2.15 s across three devices tested. Conclusion: DR-COVID is a clinically effective NLP-based conversational AI chatbot, and a promising solution for healthcare delivery in the pandemic era.


Subject(s)
COVID-19 , Deep Learning , Humans , Natural Language Processing , Artificial Intelligence , Pandemics , India
8.
Dig Dis ; 2023 Mar 13.
Article in English | MEDLINE | ID: mdl-36913917

ABSTRACT

BACKGROUND & AIMS: Due to ageing of the global population, hepatocellular carcinoma (HCC) is increasingly common among elderly patients, but outcomes after curative hepatic resection are unclear. Using a metanalytic approach, we aimed to estimate overall survival (OS), recurrence free survival (RFS) and complication rates in elderly HCC patients undergoing resection. METHODS: We searched PubMed, Embase, and Cochrane databases from inception to Nov 10, 2020 for studies reporting outcomes in elderly (age ≥ 65 years) patients with HCC undergoing curative surgical resection. Pooled estimates were generated using a random-effects model. RESULTS: We screened 8,598 articles and included 42 studies (7,778 elderly patients). The mean age was 74.45 years (95% CI 72.89-76.02), 75.54% were male (95% CI 72.53-78.32) and 66.73% had cirrhosis (95% CI 43.93-83.96). The mean tumor size was 5.50 cm (95% CI 4.71-6.29) and 16.01% had multiple tumors (95% CI 10.74-23.19). The 1-year (86.02% versus 86.66%, p=0.84) and 5-year OS (51.60% versus 53.78%) between non-elderly versus elderly patients were similar. Likewise, there were no differences in the 1-year (67.32% versus 73.26%, p=0.11) and 5-year RFS (31.57% versus 30.25%, p=0.67) in non-elderly versus elderly patients. There was a higher rate of minor complications (21.95% versus 13.71%, p=0.03) among elderly patients compared with non-elderly patients, but no difference in major complications (p=0.43) Conclusion: This data shows that overall survival, recurrence and major complications after liver resection for HCC are comparable between elderly and non-elderly patients, and may inform clinical management of HCC in this population.

9.
Ann Acad Med Singap ; 52(1): 8-16, 2023 01.
Article in English | MEDLINE | ID: mdl-36730801

ABSTRACT

INTRODUCTION: Three doses of SARS-CoV-2 mRNA vaccines have been recommended for cancer patients to reduce the risk of severe disease. Anti-neoplastic treatment, such as chemotherapy, may affect long-term vaccine immunogenicity. METHOD: Patients with solid or haematological cancer were recruited from 2 hospitals between July 2021 and March 2022. Humoral response was evaluated using GenScript cPASS surrogate virus neutralisation assays. Clinical outcomes were obtained from medical records and national mandatory-reporting databases. RESULTS: A total of 273 patients were recruited, with 40 having haematological malignancies and the rest solid tumours. Among the participants, 204 (74.7%) were receiving active cancer therapy, including 98 (35.9%) undergoing systemic chemotherapy and the rest targeted therapy or immunotherapy. All patients were seronegative at baseline. Seroconversion rates after receiving 1, 2 and 3 doses of SARS-CoV-2 mRNA vaccination were 35.2%, 79.4% and 92.4%, respectively. After 3 doses, patients on active treatment for haematological malignancies had lower antibodies (57.3%±46.2) when compared to patients on immunotherapy (94.1%±9.56, P<0.05) and chemotherapy (92.8%±18.1, P<0.05). SARS-CoV-2 infection was reported in 77 (28.2%) patients, of which 18 were severe. No patient receiving a third dose within 90 days of the second dose experienced severe infection. CONCLUSION: This study demonstrates the benefit of early administration of the third dose among cancer patients.


Subject(s)
COVID-19 , Hematologic Neoplasms , Neoplasms , Humans , SARS-CoV-2 , COVID-19/prevention & control , Treatment Outcome , Neoplasms/drug therapy , Vaccination , RNA, Messenger , Antibodies, Viral , Immunogenicity, Vaccine
10.
Physiother Theory Pract ; 39(9): 1918-1928, 2023 Sep 02.
Article in English | MEDLINE | ID: mdl-35387567

ABSTRACT

BACKGROUND: New-graduate physiotherapists experience a steep learning curve when transitioning from student to clinician. The acute hospital setting is known to present unique challenges for health clinicians, however, the preparedness of new-graduate physiotherapists for working within this setting remains unclear. PURPOSE: The aim of this study was to investigate new-graduate physiotherapists' experiences of working in acute hospital settings and their perceptions toward how their pre-professional training prepared them for this setting. METHODS: A qualitative study with a general inductive approach was used. Semi-structured interviews with new-graduate physiotherapists working in acute hospital settings were undertaken (n = 14). Interview data were subject to thematic analysis. RESULTS: Four themes were generated from the data: 1) multifactorial and high-pressure nature; 2) managing relationships; 3) realizing responsibility; and 4) constructing realistic experiences. CONCLUSION: The acute hospital setting presents unique obstacles and additional challenges when transitioning from student to clinician. New-graduates value the role of pre-professional training in their preparation for this context, however, new-graduates reflected on being sheltered from some areas of practice as students. Recommendations are suggested for education providers to adapt pre-professional training, and for employers to implement workplace strategies, which may support new-graduate physiotherapists in the acute hospital setting.


Subject(s)
Physical Therapists , Humans , Australia , Physical Therapists/education , Students , Workplace , Qualitative Research , Hospitals
11.
Rheumatology (Oxford) ; 62(5): 1757-1772, 2023 05 02.
Article in English | MEDLINE | ID: mdl-36271852

ABSTRACT

OBJECTIVES: COVID-19 infection is associated with significant morbidity in systemic lupus erythematosus but is potentially preventable by vaccination, although the impact of the myriad vaccines among SLE patients is not established. We aimed to assess the effectiveness, efficacy, acceptance and safety of COVID-19 vaccination in SLE. METHODS: We performed a systematic review of PubMed, EMBASE, CENTRAL, and Scopus publications until 8 June 2022 without language, publication year or publication status restrictions. Reports with fewer than 5 patients or incomplete information on study outcomes were excluded. Risk of bias was assessed, and results reported according to the PRISMA 2020 guidelines. RESULTS: We identified 32 studies (34 reports) comprising 8269 individuals with SLE. Post-vaccine COVID-19 infections ranged from 0 to 17% in 6 studies (5065 patients), while humoral and cellular immunogenicity was evaluated in 17 studies (976 patients) and 5 studies (112 patients), respectively. The pooled seropositivity rate was 81.1% (95% CI: 72.6, 88.5%, I2 = 85%, P < 0.01), with significant heterogeneity and higher rates for mRNA vaccines compared with non-mRNA vaccines. Adverse events and specifically lupus flares were examined in 20 studies (3853 patients) and 13 studies (2989 patients), respectively. Severe adverse events and moderate to severe lupus flares were infrequent. The pooled vaccine acceptance rate was 67.0% (95% CI: 45.2, 85.6%, I2=98%, P < 0.01) from 8 studies (1348 patients), with greater acceptance in older patients. CONCLUSION: Among SLE patients, post-vaccine COVID-19 infections, severe flares, and adverse events were infrequent, while pooled seropositivity and acceptance were high, with significant heterogeneity. These results may inform shared decision-making on vaccination during the ongoing COVID-19 pandemic. TRIAL REGISTRATION: PROSPERO, https://www.crd.york.ac.uk/PROSPERO/, CRD42021233366.


Subject(s)
COVID-19 Vaccines , COVID-19 , Lupus Erythematosus, Systemic , Aged , Humans , COVID-19/complications , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/adverse effects , Lupus Erythematosus, Systemic/complications , Pandemics , Vaccination/methods , Vaccines/adverse effects
12.
Nat Mater ; 21(12): 1396-1402, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36396958

ABSTRACT

Cations with suitable sizes to occupy an interstitial site of perovskite crystals have been widely used to inhibit ion migration and promote the performance and stability of perovskite optoelectronics. However, such interstitial doping inevitably leads to lattice microstrain that impairs the long-range ordering and stability of the crystals, causing a sacrificial trade-off. Here, we unravel the evident influence of the valence states of the interstitial cations on their efficacy to suppress the ion migration. Incorporation of a trivalent neodymium cation (Nd3+) effectively mitigates the ion migration in the perovskite lattice with a reduced dosage (0.08%) compared to a widely used monovalent cation dopant (Na+, 0.45%). The photovoltaic performances and operational stability of the prototypical perovskite solar cells are enhanced with a trace amount of Nd3+ doping while minimizing the sacrificial trade-off.

13.
Br J Anaesth ; 129(2): 154-162, 2022 08.
Article in English | MEDLINE | ID: mdl-35729010

ABSTRACT

BACKGROUND: Direct oral anticoagulants (DOACs) have been increasingly used as anticoagulation therapy in the postoperative period. However, their effectiveness in post-cardiac surgical atrial fibrillation is yet to be determined. METHODS: We conducted a meta-analysis, searching three international databases from 1 January 2003 to 26 January 2022 for studies reporting on DOACs in at least 10 adult patients (>18 yr of age) with post-cardiac surgical atrial fibrillation. The primary outcomes were major neurological events and bleeding; secondary outcomes were mortality, hospital and ICU length of stay, cost, and other complications from therapy. We included studies of any design, including RCTs, cohort studies with and without propensity score matching methods, and single-armed case series. RESULTS: Twelve studies (8587 DOACs; 8315 warfarin) were included in this meta-analysis. The incidences of postoperative bleeding and major neurological events with DOACs were 7.3% (95% confidence interval [CI]: 3.4-14.7%) and 2.2% (95% CI: 0.9-4.9%), respectively. The incidence of major neurological events was lower in high-risk patients, including those with hypertension and higher CHA2DS2-VASc score, whereas patients with prior transient ischaemic attack or stroke had higher incidence of bleeding. Trial sequential analysis revealed that the cumulative Z-curve crossed the conventional boundary of benefit. Compared with warfarin, DOACs reduced the risk of bleeding (relative risk [RR] 0.74; 95% CI: 0.62-0.89; P=0.0011) and major neurological events (RR 0.63; 95% CI: 0.48-0.83; P=0.0012) but not mortality (RR 1.02; 95% CI: 0.77-1.35; P=0.090). CONCLUSIONS: DOACs reduced bleeding and major neurological events in patients with post-cardiac surgical atrial fibrillation, appearing safer than warfarin in this context. However, which specific DOAC provides the most effective anticoagulation in this patient population needs further investigation. CLINICAL TRIAL REGISTRATION: PROSPERO CRD42021282777.


Subject(s)
Atrial Fibrillation , Cardiac Surgical Procedures , Stroke , Administration, Oral , Adult , Anticoagulants/adverse effects , Atrial Fibrillation/drug therapy , Cardiac Surgical Procedures/adverse effects , Humans , Postoperative Hemorrhage/epidemiology , Postoperative Hemorrhage/prevention & control , Stroke/epidemiology , Stroke/etiology , Stroke/prevention & control , Warfarin
14.
Nature ; 605(7909): 268-273, 2022 05.
Article in English | MEDLINE | ID: mdl-35292753

ABSTRACT

Optoelectronic devices consist of heterointerfaces formed between dissimilar semiconducting materials. The relative energy-level alignment between contacting semiconductors determinately affects the heterointerface charge injection and extraction dynamics. For perovskite solar cells (PSCs), the heterointerface between the top perovskite surface and a charge-transporting material is often treated for defect passivation1-4 to improve the PSC stability and performance. However, such surface treatments can also affect the heterointerface energetics1. Here we show that surface treatments may induce a negative work function shift (that is, more n-type), which activates halide migration to aggravate PSC instability. Therefore, despite the beneficial effects of surface passivation, this detrimental side effect limits the maximum stability improvement attainable for PSCs treated in this way. This trade-off between the beneficial and detrimental effects should guide further work on improving PSC stability via surface treatments.

15.
Science ; 375(6583): eabj1186, 2022 02 25.
Article in English | MEDLINE | ID: mdl-35201885

ABSTRACT

The A cation in ABX3 organic-inorganic lead halide perovskites (OLHPs) was conventionally believed to hardly affect their optoelectronic properties. However, more recent developments have unraveled the critical role of the A cation in the regulation of the physicochemical and optoelectronic properties of OLHPs. We review the important breakthroughs enabled by the versatility of the A cation and highlight potential opportunities and unanswered questions related to the A cation in OLHPs.

16.
J Med Virol ; 94(6): 2460-2470, 2022 06.
Article in English | MEDLINE | ID: mdl-35171507

ABSTRACT

Coronavirus Disease 2019 (COVID-19) serology has an evolving role in the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, its use in hospitalized patients with acute respiratory symptoms remains unclear. Hospitalized patients with acute respiratory illness admitted to an isolation ward were recruited. All patients had negative nasopharyngeal swab polymerase chain reaction (PCR) for SARS-CoV-2. Serological studies using four separate assays (cPass: surrogate neutralizing enzyme-linked immunosorbent assay [ELISA]; Elecsys: N-antigen based chemiluminescent assay; SFB: S protein flow-based; epitope peptide-based ELISA) were performed on stored plasma collected from patients during the initial hospital stay, and a convalescent visit 4-12 weeks later. Of the 51 patients studied (aged 54, interquartile range 21-84; 62.7% male), no patients tested positive on the Elecsys or cPass assays. Out of 51 patients, 5 had antibodies detected on B-cell Epitope Assay and 3/51 had antibodies detected on SFB assay. These 8 patients with positive serological test to COVID-19 were more likely to have a high-risk occupation (p = 0.039), bacterial infection (p = 0.028), and neutrophilia (p = 0.013) during their initial hospital admission. Discrepant COVID-19 serological findings were observed among those with recent hospital admissions and bacterial infections. The positive serological findings within our cohort raise important questions about the interpretation of sero-epidemiology during the current pandemic.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay , Female , Fever , Humans , Male , Pandemics , Polymerase Chain Reaction , SARS-CoV-2/genetics
17.
Small ; 18(8): e2103887, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34873843

ABSTRACT

Superior bandgap tunability enables solution-processed halide perovskite a promising candidate for multi-junction photovoltaics (PVs). Particularly, optically coupling wide-gap perovskite by stacking with commercially available PVs such as silicon and CIGS (also known as 4-terminal tandem) simplifies the technology transfer process, and further advances the commercialization potential of perovskite technology. However, compared with matured PV materials and the phase-pure FAPbI3 , wide-gap perovskite still suffers from huge voltage deficits. Here, the authors take advantage of the synergetic effect behind a sequential fluoride and organic ammonium salt surface passivation strategy to control non-radiative energy losses, and obtained a 17.7% efficiency in infrared-transparent wide-gap perovskite solar cells (21.1% for opaque device), and achieved efficiencies of over 25% when stacked with commercial Si and CIGS products with original PCEs of 18-20% under a 4-terminal working condition.

18.
Ann Work Expo Health ; 66(2): 246-259, 2022 02 18.
Article in English | MEDLINE | ID: mdl-34564717

ABSTRACT

PURPOSE: Medical masks have inferior filtration efficiency and fit to filtering facepiece respirators (FFRs) but are widely used in healthcare and the community. These masks are intended for disposal after use but in the event of mask shortage re-use after reprocessing may be an option. We investigated eight reprocessing methods that each involved washing or soaking in liquid, are likely to eliminate respiratory viruses, and are safe and available in most community and healthcare settings. METHODS: Three brands of EN 14683 standards-compliant commercial medical mask were each reprocessed 10 times by one of eight methods. We measured filtration efficiency for poly-dispersed sodium chloride particles and pressure differential. RESULTS: Compared with new medical masks, reprocessed masks had significantly reduced filtration efficiency. The reduction was mild-moderate (6.5-25.8%) after warm water wash, hot water soak or boiling water soak; and moderate-large (24.1-51.5%) after detergent, soap or laundry machine wash, or bleach soak. There were mixed and minor changes in pressure differential. Most reprocessed standards-compliant masks had better filtration efficiency than new non-standard commercial masks and then cotton and cotton-polyester mix fabric samples, even triple-layered fabrics. CONCLUSIONS: High-quality commercial medical masks reprocessed 10 times by water immersion methods had better filtration efficiency than new non-standard masks and washable fabrics. These findings have particular relevance for community and low-resource healthcare settings.


Subject(s)
COVID-19 , Occupational Exposure , Humans , Immersion , Masks , SARS-CoV-2
20.
ACS Nano ; 16(1): 1231-1238, 2022 Jan 25.
Article in English | MEDLINE | ID: mdl-34932319

ABSTRACT

Semitransparent organic photovoltaics (OPVs) have drawn significant attention for their promising potential in the field of building integrated photovoltaics such as energy-generating greenhouses. However, the conflict between the need to attain satisfying average visible transmittances for greenhouse applications and the need to maintain high power conversion efficiencies is limiting the commercialization of semitransparent OPVs. A major manifestation of this issue is the undermining of charge carrier extraction efficiency when opaque, visible-light-absorbing electrodes are substituted with semitransparent ones. Here, we incorporated a dual-function p-type compatible interlayer to modify the interface of the hole-transporting layer and the ultrathin electrode of the semitransparent devices. We find that the p-type interlayer not only enhances the charge carrier extraction of the electrode but also increases the light transmittance in the wavelength range of 400-450 nm, which covers most of the photosynthetic absorption spectrum. The modified semitransparent devices reach a power conversion efficiency of 13.7% and an average visible transmittance of 22.2%.

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