Rapid Vapor-Phase Deposition of High-Mobility p-Type Buffer Layers on Perovskite Photovoltaics for Efficient Semi-Transparent Devices

Perovskite solar cells (PSCs) with transparent electrodes can be integrated with existing solar panels in tandem configurations to increase the power conversion efficiency. A critical layer in semi-transparent PSCs is the inorganic buffer layer, which protects the PSC against damage when the transparent electrode is sputtered on top. The development of n-i-p structured semi-transparent PSCs has been hampered by the lack of suitable p-type buffer layers. In this work we develop a p-type CuOx buffer layer, which can be grown uniformly over the perovskite device without damaging the perovskite or organic hole transport layer. The CuOx layer has high hole mobility (4.3 ± 2 cm2 V-1 s-1), high transmittance (>95%), and a suitable ionization potential for hole extraction (5.3 ± 0.2 eV). Semi-transparent PSCs with efficiencies up to 16.7% are achieved using the CuOx buffer layer. Our work demonstrates a new approach to integrate n-i-p structured PSCs into tandem configurations, as well as enable the development of other devices that need high quality, protective p-type layers.EPSRC Department Training Partnership studentship (No: EP/N509620/1), as well as Bill Welland. T.N.H. acknowledges funding from the EPSRC Centre for Doctoral Training in Graphene Technology (No. EP/L016087/1) and the Aziz Foundation. W.-W.L. and J.L.M.-D. acknowledge support from the EPSRC (Nos.: EP/L011700/1, EP/N004272/10), and the Isaac Newton Trust (Minute 13.38(k)). M.N. and J.L.M.-D. acknowledge financial support from EPSRC (No. EP/P027032/1). S. D. S. acknowledges support from the Royal Society and Tata Group (UF150033). R.L.Z.H. acknowledges support from the Royal Academy of Engineering under the Research Fellowship scheme (No.: RF\201718\1701), the Centre of Advanced Materials for Integrated Energy Systems (EPSRC Grant No. EP/P007767/1), the Isaac Newton Trust (Minute 19.07(d)), and the Kim and Juliana Silverman Research Fellowship at Downing College, Cambridge

Data and Codes for Experimentally Validated Inverse design of Multi Property Fe-Co-Ni-alloys

<p>Data and codes for the research work "Experimentally Validated Inverse design of Multi-Property Fe-Co-Ni alloys" authored by Shakti P. Padhy, Varun Chaudhary, Yee-Fun Lim, Ruiming Zhu, Muang Thway, Kedar Hippalgaonkar, & Raju V. Ramanujan.</p><p>Github link: https://github.com/Shakti-95/Data-and-Codes-for-Experimentally-Validated-Inverse-design-of-Multi-Property-Fe-Co-Ni-alloys</p&gt

Bayesian spatiotemporal analysis of malaria infection along an international border: Hlaingbwe Township in Myanmar and Tha-Song-Yang District in Thailand

Abstract Background One challenge in moving towards malaria elimination is cross-border malaria infection. The implemented measures to prevent and control malaria re-introduction across the demarcation line between two countries require intensive analyses and interpretation of data from both sides, particularly in border areas, to make correct and timely decisions. Reliable maps of projected malaria distribution can help to direct intervention strategies. In this study, a Bayesian spatiotemporal analytic model was proposed for analysing and generating aggregated malaria risk maps based on the exceedance probability of malaria infection in the township-district adjacent to the border between Myanmar and Thailand. Data of individual malaria cases in Hlaingbwe Township and Tha-Song-Yang District during 2016 were extracted from routine malaria surveillance databases. Bayesian zero-inflated Poisson model was developed to identify spatial and temporal distributions and associations between malaria infections and risk factors. Maps of the descriptive statistics and posterior distribution of predicted malaria infections were also developed. Results A similar seasonal pattern of malaria was observed in both Hlaingbwe Township and Tha-Song-Yang District during the rainy season. The analytic model indicated more cases of malaria among males and individuals aged ≥ 15 years. Mapping of aggregated risk revealed consistently high or low probabilities of malaria infection in certain village tracts or villages in interior parts of each country, with higher probability in village tracts/villages adjacent to the border in places where it could easily be crossed; some border locations with high mountains or dense forests appeared to have fewer malaria cases. The probability of becoming a hotspot cluster varied among village tracts/villages over the year, and some had close to no cases all year. Conclusions The analytic model developed in this study could be used for assessing the probability of hotspot cluster, which would be beneficial for setting priorities and timely preventive actions in such hotspot cluster areas. This approach might help to accelerate reaching the common goal of malaria elimination in the two countries

SPATIO-TEMPORAL ANALYSIS OF MALARIA INCIDENCE ALONG HLAINGBWE TOWNSHIP IN MYANMAR AND THA SONG YANG DISTRICT IN THAILAND

Background: Malaria stays a serious public health problem in many countries of the world. The border regions are difficult to control for the malaria elimination due to the importation or reintroduction of malaria. A key to address such problem is reinforcing of surveillance activities with rapid identification.  The objective of the study was to describe the malaria incidence rate and analyze the space and time distribution of malaria incidence rate in the high endemic border areas between Myanmar andThailand, the Hlaingbwe Township and Tha Song Yang District.  Methodology: Daily malaria data were collected, using a passive surveillance system, from patients visiting local health facilities in both Tha Song Yang and Hlaingbwe regions. ArcMap software version 10.4.1 was used to describe the disease mapping of malaria incidence rate in both regions. Results: Compared to their counterparts, male gender had higher malaria incidence rates in both Tha Song Yang and Hlaingbwe regions. Non-Thai people had higher incidence rate than Thai in Tha Song Yang district. The higher incidence rates had seasonal pattern and the pattern was similar in both regions. The areas with a higher incidence rate could be seen in both inner side and along Thai- Myanmar border (upper and lower parts) in Tha Song Yang area. But in Hlaingbwe Township, the higher incidence rate occurred only in the inner and upper parts except for Me La Yaw and Tar Le areas which are situated along the Thai-Myanmar border. Along the border, the higher incidence rates were connected to the adjacent area in upper and lower parts between these two regions. Conclusion: The descriptive statistics and presented map in this study gave the health policy makers an important overview of malaria situation in this regions in order to intervene high risk areas more effectively, and distribute the resources in a useful manner

Impacts of light illumination on monocrystalline silicon surfaces passivated by atomic layer deposited Al2O3 capped with plasma-enhanced chemical vapor deposited SiNX

10.7567/JJAP.56.08MB01JAPANESE JOURNAL OF APPLIED PHYSICS56

Four-terminal perovskite on silicon tandem solar cells optimal measurement schemes

Semitransparent perovskite solar cells (SCs) and their potential integration with silicon SCs in tandem configurations attract significantly increasing interest in the photovoltaics community. In addition to being highly spectrally complementary, these perovskite and silicon SCs have very different optimal‐performing sizes and consequently ideal measurement schemes for their integration in four‐terminal (4T) tandem configurations need to be investigated in detail. Herein, the effect of different active areas on both perovskite and silicon SCs on their photovoltaic performances is investigated. Furthermore, the commonly used filtering 4T tandem measurement scheme (named as filtered) is systematically compared with the size‐matching scheme (named as masked) demonstrating that when using the same top semitransparent perovskite and bottom silicon SCs in different measurements schemes, the total 4T tandem power conversion efficiency (PCE) can differ by more than 1%. The concepts presented here highlight the importance of optimal measurement schemes to assess 4T tandem PCE and rationalize the effect of compromise between the subcells size matching and the identification of the maximum PCE potential.NRF (Natl Research Foundation, S’pore)Accepted versio

Ultra-thin GaAs double-junction solar cell with carbon-doped emitter

We address the challenge in depositing ultra-thin GaAs cells (<200 nm) using a more scalable process (metal-organic chemical vapor deposition). We present results for a GaAs/GaAs double-junction solar cell with a 110-nm-thick top cell. Current, voltage, fill factor, and efficiency of this architecture are improved by replacing the zinc doping in the emitter of the top cell with carbon doping. We find that the carbon doping results in a well-defined active junction profile that agrees well with the secondary ion mass spectroscopy measurement. Additionally, we find that the carbon doping coincides with the incorporation of indium in the emitter. We postulate that the incorporation of indium relieves stress in the material, which results in a smoother morphology of the GaAs film. Finally, we show the efficiency achieved with the carbon-doping process is 19.2% for the GaAs/GaAs dual junction cell. The open circuit voltage is 1.087 V for the ultra-thin (110 nm) GaAs top cell and 2.08 V for the dual junction cell.NRF (Natl Research Foundation, S’pore)EDB (Economic Devt. Board, S’pore

Ultra-Thin GaAs Double-Junction Solar Cell With Carbon-Doped Emitter

10.1109/JPHOTOV.2018.2870721IEEE JOURNAL OF PHOTOVOLTAICS861627-163

Sub-10 nm mixing and alloying of Cu-Ag and Cu-Ni via accelerated solid diffusion

Development of nanoscale multicomponent solid inorganic materials is often hindered by slow solid diffusion kinetics and poor precursor mixing in conventional solid-state synthesis. These shortcomings can be alleviated by combining nanosized precursor mixtures and low temperature reaction, which could reduce crystal growth and accelerate the solid diffusion at the same time. However, high throughput production of nanoparticle mixtures with tunable composition via conventional synthesis is very challenging. In this work, we demonstrate that ∼10 nm homogeneous mixing of sub-10 nm nanoparticles can be achieved via spark nanomixing at room temperature and pressure. Kinetically driven Spark Plasma Discharge nanoparticle generation and ambient processing conditions limit particle coarsening and agglomeration, resulting in sub-10 nm primary particles of as-deposited films. The intimate mixing of these nanosized precursor particles enables intraparticle diffusion and formation of Cu/Ni nanoalloy during subsequent low temperature annealing at 100 °C. We also discovered that cross-particle diffusion is promoted during the low-temperature sulfurization of Cu/Ag which tends to phase-segregate, eventually leading to the growth of sulfide nanocrystals and improved homogeneity. High elemental homogeneity, small diffusion path lengths, and high diffusibility synergically contribute to faster diffusion kinetics of sub-10 nm nanoparticle mixtures. The combination of ∼10 nm homogeneous precursors via spark nanomixing, low-temperature annealing, and a wide range of potentially compatible materials makes our approach a good candidate as a general platform toward accelerated solid state synthesis of nanomaterials.Agency for Science, Technology and Research (A*STAR)National Research Foundation (NRF)The authors acknowledge funding from the Accelerated Materials Development for Manufacturing Program (Grant A1898b0043) and the Structural Metals and Alloys Program (Grant A18B1b0061) fund by the Agency for Science, Technology and Research. A.D.H. acknowledges Career Development Award (Grant 192D8230) from Agency for Science, Technology and Research. K.H. also acknowledges support from the NRF Fellowship (Grant NRF-NRFF13-2021-0011)