Toward The Development Of Printable Perovskite Solar Cells

PSCs have become a significant performer in third generation photovoltaics with power conversion efficiency, greater than 22% for active areas less than 1 cm2. However, with efficiency improvement, concerns regarding the operational stability and industrial production firstly resolved to grow into commercially viable PSCs. To address above stated issues most stable, yet efficient Monolithic PSCs (mPSCs) are structured. The mPSCs are having compact TiO2, mesoporous TiO2, mesoporous ZrO2, and mesoporous carbon electrode layers in optimal thicknesses on the FTO substrate. Fabrication protocol for all the layers which is easily scalable for large area mPSCs manufacturing is highly required. Furthermore top carbon electrode materials those are stable and behaves as protective casing to make PSCs stable has also been highly desired. Hence, in this project our aim is to optimize top carbon layer and study photophysical processes inside the mPSCs. This research work is mainly divided into three parts. The first part of the dissertation described carbon film fabrication by screen printing technique and their investigation at different annealing temperature . Influence of annealing temperatures on the electrical, morphological and structural properties of the carbon film has been discussed. It is shown that a low annealing temperature is good for better adherence of the conductive carbon films, however, temperatures higher than 300°C are required to produce efficient mPSCs. A sintering temperature of 400°C showed the highest device efficiency of 13.2%. It is important to correlate all the physical properties/processes taking place in the mPSCs to gain a deeper understanding of mPSCs operation: What is the role of the contacts? What limits the efficiency of existing perovskite solar cells? How many charge carriers are there in the cell under operating condition. Hence, in second part, Electrochemical Impedance spectroscopy (EIS) spectrum has been described, which is performed on the mPSCs having highest efficiency during previous experiments. The EIS spectrum of mPSCs quantitatively explains the role of contacts, layers, charge generation, drift and diffusion of charge carriers and recombination. This would further provide insight into the performance-limiting physical processes of mPSCs. The microstructure or morphology of the perovskite crystals inside mesoporous TiO2 and mesoporous ZrO2 have significant effect on the mPSCs performance and stability. Therefore, to achieve higher mPSCs device performance, one-dimensional microrods (4mm-5mm) of PbI2 and CH3NH3PbI3 (MAPbI3) is fabricated in the 3rd part. These microrods consist of unique structural and morphological properties which are grown at room temperature. The XRD and TEM analyses confirm the existence of strong interactions between different stable groups in the crystals. The morphological studies approve crack free morphology of PbI2 and MAPbI3 micro-rods. The above results are expected to have a big effect on solar cell and photo-detection industry by fostering improvement of thin-film opto-electronic devices

Response of drip irrigated Broccoli (Brassica oleracea var. italica) in different irrigation levels and frequencies at field level

Geometric increase in population coupled with rapid urbanization, industrialization and agricultural development are causing increased pressure on global water resources. Agriculture is the largest consumer of fresh water resources, thus the scope of enhancing water productivity in agriculture is taken to be the priority area of research. The right amount and frequency of irrigation is essential for optimum use of limited water resources for crop production as well as management. A field experiment with split plot design was carried out during November to February 2015-16 at PFDC (Precision Farming Development Centre), Water Technology Centre, IARI, New Delhi to study the effect of different irrigation levels and frequencies on Broccoli (Brassica oleracea var. italica) under drip irrigation. The experiment included three levels of irrigation frequencies: N1 (once every day), N2 (once every 2 days) and N3 (once every 3 days) with different irrigation levels of 100, 80 and 60 % of crop evapotranspiration (ETc). Results revealed that drip irrigation frequency significantly (p<0.05) affected the broccoli yield. The maximum yield (24.46±0.18 t/ha) was obtained with 80% of ETc with once in 2 days irrigation followed by 100% of ETc with once in 2 days. Lowest yield (16.53±0.1 t/ha) was obtained at 60% of ETc at once in 3 days irrigation. Overall, it was observed that irrigation on 80% of ETc with once in two days is an appropriate cycle for optimum yield of broccoli

A comparative study to evaluate diagnostic accuracy and correlation between saline infusion sonography, hysterosalpingography and diagnostic hysterolaparoscopy in infertility

Background: Till date hysterosalpingography (HSG) remains the first-line method to detect tubal patency and to find out any uterine abnormalities in infertile female while diagnostic hysterolaparoscopy (DHL)  is considered to be the gold standard method, it is during last decades only that saline infusion sonography (SIS)/ sonohysterography (SHG) has emerged as an efficacious method of checking tubal patency and uterine anatomy as well. The present study aims to compare all three methods viz- SIS, HSG and DHL and to evaluate the correlation between these methods.Methods: 98 infertile females of age group 18-35 years with normal Hormonal profile without any male factor infertility, were prospectively selected from the outpatient department of obstetrics and gynecology, GMH Rewa, Madhya Pradesh over one year from 1st August 2016 to 31st July 2017.Results: Diagnostic accuracy (sensitivity and specificity) of SIS was found to be more than HSG for both tubal patency and uterine abnormalities detection. SIS has less numbers of false positive and false negative rates as compared to HSG. DHL was found to be much superior to both SIS and HSG, also detected additional findings in multiple sites like pelvis, tubes and the uterus on the same setting which were missed on SIS and HSG.Conclusions: SIS may replace HSG as a first step screening method for tubal patency detection, as it has more diagnostic accuracy than HSG and better correlation with DHL and has many advantages and minimal disadvantages as compared to HSG

A prospective study of demographic profile, risk factors and pregnancy outcome in Hepatitis B and Hepatitis C virus positive pregnant women in a tertiary care centre

Background: Viral hepatitis is the most common liver disease in pregnancy and is also the most common cause of jaundice in pregnancy in tropical countries. Risk factors for transmission are intravenous drug abuse, surgical and dental procedures done without adequate sterilization of instruments, sexual route etc. Early diagnosis and management can prevent maternal and fetal complications. This study was done to evaluate the frequency, risk factors and pregnancy outcome in hepatitis B virus (HBV) and hepatitis C virus (HCV) positive antenatal women.Methods: This case control study was conducted in Teerthankar Mahaveer Medical College and Research Centre, Moradabad, Uttar Pradesh, India from January 2017 to June 2018 on total 2511 pregnant women. The serum samples were checked for presence of hepatitis B surface antigen (HBsAg) and presence of IgG antibodies to HCV. Analysis of sociodemographic profile, risk factors and pregnancy outcome were done in all HBV and HCV positive women.Results: Out of 2511 pregnant women, 292 were tested positive for hepatitis. Maximum number of women were in the age group of 21-30 years. Most of the seropositive women were multipara. Frequency of positivity was maximum for HCV (67.1%). The risk factors for transmission in study population were intravenous drug abuse, blood transfusion, history of surgery and tattooing.Conclusions: Hepatitis infection rate is increasing. Universal screening for HBV and HCV can be recommended in pregnant women in developing countries. Education and awareness of public and health care workers can reduce the risk of transmission.

Electrical equivalent circuit (EEC) based impedance spectroscopy analysis of HTM free perovskite solar cells

Monolithic perovskite solar cells (mPSCs) are the multi-layered organic-inorganic hybrid cells that have been focused due to the affordable cost, ease of fabrication and noteworthy power conversion efficiency (PCE). In this research, we have carried out a systematic study to understand the physical phenomenon inside successive layers of the mpscs using the impedance spectroscopy (IS). This study was performed on the optimized mpscs with power conversion efficiency over 13%, where CH3NH3PbI3, perovskite has been used as light absorber. The internal electrical processes at the interfaces of the layers of mPSCs devices have been studied and correlated to produce electrical equivalent circuit of overall devic

Amplified fragment length polymorphism of clinical and environmental Vibrio cholerae from a freshwater environment in a cholera-endemic area, India

<p>Abstract</p> <p>Background</p> <p>The region around Chandigarh in India has witnessed a resurgence of cholera. However, isolation of <it>V. cholerae </it>O1 from the environment is infrequent. Therefore, to study whether environmental nonO1-nonO139 isolates, which are native to the aquatic ecosystem, act as precursors for pathogenic O1 strains, their virulence potential and evolutionary relatedness was checked.</p> <p>Methods</p> <p><it>V. cholerae </it>was isolated from clinical cases of cholera and from water and plankton samples collected from freshwater bodies and cholera-affected areas. PCR analysis for the <it>ctxA, ctxB, tcpA, toxT </it>and <it>toxR </it>genes and AFLP with six primer combinations was performed on 52 isolates (13 clinical, 34 environmental and 5 reference strains).</p> <p>Results</p> <p>All clinical and 3 environmental isolates belonged to serogroup O1 and remaining 31 environmental <it>V. cholerae </it>were nonO1-nonO139. Serogroup O1 isolates were <it>ctxA, tcpA </it>(ElTor), <it>ctxB </it>(Classical), <it>toxR </it>and <it>toxT </it>positive. NonO1-nonO139 isolates possessed <it>toxR</it>, but lacked <it>ctxA </it>and <it>ctxB</it>; only one isolate was positive for <it>toxT </it>and <it>tcpA</it>. Using AFLP, 2.08% of the <it>V. cholerae </it>genome was interrogated. Dendrogram analysis showed one large heterogeneous clade (n = 41), with two compact and distinct subclades (1a and 1b), and six small mono-phyletic groups. Although <it>V. cholerae </it>O1 isolates formed a distinct compact subclade, they were not clonal. A clinical O1 strain clustered with the nonO1-nonO139 isolates; one strain exhibited 70% similarity to the Classical control strain, and all O1 strains possessed an ElTor variant-specific fragment identified with primer ECMT. Few nonO1-nonO139 isolates from widely separated geographical locations intermingled together. Three environmental O1 isolates exhibited similar profiles to clinical O1 isolates.</p> <p>Conclusion</p> <p>In a unique study from freshwater environs of a cholera-endemic area in India over a narrow time frame, environmental <it>V. cholerae </it>population was found to be highly heterogeneous, diverse and devoid of major virulence genes. O1 and nonO1-nonO139 isolates showed distinct lineages. Clinical isolates were not clonal but were closely related, indicating accumulation of genetic differences over a short time span. Though, environment plays an important role in the spread of cholera, the possibility of an origin of pathogenic O1 strains from environmental nonO1-nonO139 strains seems to be remote in our region.</p

Metal halide-based photodetector using one-dimensional MAPbI3 micro rods

In the present work, we report the fabrication of a photodetector using methylammonium lead iodide perovskite (MAPbI3) micro rod. Photosensitivity of the Ag/MAPbI3/Ag photodetector has been studied under various light intensities ranging from 10 to 100 mW/cm2. The MAPbI3 perovskite micro rod-based photodetector shows a high on/off ratio (4.47 × 105), and fast response & recovery times (2.7 ms, each), as compared to the photodetectors using perovskite films. This work could initiate new perspectives for perovskite micro rods to be employed in high-performance optoelectronic devices.Open Access funding provided by the Qatar National Library. The authors are highly thankful to the Center of Advanced Materials (CAM), Qatar University, for providing the lab facilities to perform this work

Designing a mobile health smokeless tobacco cessation intervention in Odisha, India: User and provider perspectives

OBJECTIVE: There is limited evidence on the development of mobile health (mHealth) interventions for smokeless tobacco (SLT) cessation, despite its widespread use in South Asia. This formative qualitative study explored the perceptions of tobacco users and healthcare providers (HCPs) regarding developing a mHealth intervention for SLT cessation. METHODS: This was a qualitative study using in-depth interviews (IDIs) with tobacco users (n = 26) and primary care physicians (PCPs) (n = 5) and focus group discussions (FGDs) with counsellors (n = 2) in four urban primary health centres (UPHCs) in Berhampur, Odisha from February to March 2020. The data were coded and analysed by two researchers using a framework analysis method. The discussion guides and initial codes were developed based on the Transtheoretical Model (TTM) of behaviour change. RESULTS: The results were elaborated under four themes: (1) Current scenario of SLT use; (2) Barriers and facilitators for quitting SLT; (3) Barriers and facilitators for mHealth counselling; and (4) Design and delivery of the proposed intervention. SLT use was prevalent in the community regardless of sociodemographic factors. Peer factors accounted for both tobacco consumption as well as considering cessation. Participants considered mobile message counselling helpful and acceptable. Not having a mobile phone and illiteracy were identified as barriers while ease of access and rising popularity of social media applications were considered facilitators to the use of mHealth for quitting tobacco. Participants preferred messages that were pictorial, short and simple, in the local language, and tailored to individual's needs. CONCLUSIONS: This is the first study that provides evidence within the Indian context that the text messaging platform may be used for delivering an SLT cessation intervention. The integration of a theoretical basis and research findings from target users can guide future intervention development