Routes for realizing high-performing Si solar cells by using periodic structures

Yadav, Pankaj,Patel, Malkeshkumar,Kim, Hyunyub,Cho, Yunae,Kim, Hyunki,Kim, Joondong,Yi, Junsin,Kim, Dong-Wook Elsevier 2017 Materials research bulletin Vol.94 No.-

<P><B>Abstract</B></P> <P>Theoretical suggestion indicated the substantial improvement of solar cells by using periodic structures. Yet, the promise has not been practically realized due to the lack of electrical analyses of periodical light-absorbing structure. Here, we report the record high-efficiency of 16.9% for periodically patterned silicon (Si) solar cells. Periodic Si micro-pillars were fabricated for large-scale solar cells. The Si pillars with a height of about 5μm provided significantly enlarged light-active surface, which improved the photo-generated carrier collection efficiency. From optical aspects, the pillar structures reduced light reflection and hence effectively drove more photons into the absorber layer. Additionally, the enhanced pillar-structured Si surface definitely contributed to reduce an electrical resistance of a solar cell. We demonstrated that the surficial enhanced Si design could be a promising approach for high-efficient solar cell applications. We may suggest a route for the optimum electrical designs of periodic structured solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The record high-efficiency of 16.9% for periodically patterned Si solar cells. </LI> <LI> Optical and electrical benefits of periodic microscale Si structures. </LI> <LI> Design routes for realizing high-performing periodic Si solar cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Critical aspects of impedance spectroscopy in silicon solar cell characterization: A review

Yadav, Pankaj,Pandey, Kavita,Bhatt, Vishwa,Kumar, Manoj,Kim, Joondong PERGAMON 2017 RENEWABLE AND SUSTAINABLE ENERGY REVIEWS Vol.76 No.-

<P><B>Abstract</B></P> <P>Solar energy generation and utilization is dominated by silicon based solar photovoltaic technology, which has a market share of 80–90% of the solar photovoltaic industry worldwide. The performance indicating parameters of silicon solar cells include power conversion efficiency, series and shunt resistance, ideality factor and built-in potential. These parameters are mostly characterized by DC techniques, which is limited by its insufficiency to identify other important parameters such as interfacial diffusion and transition capacitance and resistive and capacitive components of p-p<SUP>+</SUP> interface of a silicon solar cell. Impedance spectroscopy is considered to be one of the most promising techniques for the characterization of abovementioned performance limiting parameters of a solar cell. In order to address the decoupling of various physical processes associated with different interfaces of a solar cell, quantitative analysis of the impedance spectroscopic data is required. An appropriate mathematical model is frequently used to correlate with the physical performance limiting parameters. This review presents a complete overview of the required mathematical models to analyse impedance spectroscopic data for interfacial processes of silicon solar cell.</P>

Interfacial Energetics of All Oxide Transparent Photodiodes

Pankaj Yadav,Hong-sik Kim,Malkeshkumar Patel,Joondong Kim 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.2

Comparative Performance of Line Probe Assay (Version 2) and Xpert MTB/RIF Assay for Early Diagnosis of Rifampicin-Resistant Pulmonary Tuberculosis

( Raj Narayan Yadav ),( Binit Kumar Singh ),( Rohini Sharma ),( Jigyasa Chaubey ),( Sanjeev Sinha ),( Pankaj Jorwal ) 대한결핵 및 호흡기학회 2021 Tuberculosis and Respiratory Diseases Vol.84 No.3

Background: The emergence of drug-resistant tuberculosis (TB), is a major menace to cast off TB worldwide. Line probe assay (LPA; GenoType MTBDRplus ver. 2) and Xpert MTB/RIF assays are two rapid molecular TB detection/diagnostic tests. To compare the performance of LPA and Xpert MTB/RIF assay for early diagnosis of rifampicin-resistant (RR) TB in acid-fast bacillus (AFB) smear-positive and negative sputum samples. Methods: A total 576 presumptive AFB patients were selected and subjected to AFB microscopy, Xpert MTB/RIF assay and recent version of LPA (GenoType MTBDRplus assay version 2) tests directly on sputum samples. Results were compared with phenotypic culture and drug susceptibility testing (DST). DNA sequencing was performed with rpoB gene for samples with discordant rifampicin susceptibility results. Results: Among culture-positive samples, Xpert MTB/RIF assay detected Mycobacterium tuberculosis (Mtb) in 97.3% (364/374) of AFB smear-positive samples and 76.5% (13/17) among smear-negative samples, and the corresponding values for LPA test (valid results with Mtb control band) were 97.9% (366/374) and 58.8% (10/17), respectively. For detection of RR among Mtb positive molecular results, the sensitivity of Xpert MTB/RIF assay and LPA (after resolving discordant phenotypic DST results with DNA sequencing) were found to be 96% and 99%, respectively. Whereas, specificity of both test for detecting RR were found to be 99%. Conclusion: We conclude that although Xpert MTB/RIF assay is comparatively superior to LPA in detecting Mtb among AFB smear-negative pulmonary TB. However, both tests are equally efficient in early diagnosis of AFB smear-positive presumptive RR-TB patients.

Transparent Cu₄O₃/ZnO heterojunction photoelectric devices

Kim, Hong-Sik,Yadav, Pankaj,Patel, Malkeshkumar,Kim, Joondong,Pandey, Kavita,Lim, Donggun,Jeong, Chaehwan Academic Press 2017 Superlattices and microstructures Vol.112 No.-

<P><B>Abstract</B></P> <P>The present article reports the development of flexible, self-biased, broadband, high speed and transparent heterojunction photodiode, which is essentially important for the next generation electronic devices. We grow semitransparent p-type Cu<SUB>4</SUB>O<SUB>3</SUB> using the reactive sputtering method at room temperature. The structural and optical properties of the Cu<SUB>4</SUB>O<SUB>3</SUB> film were investigated by using the X-ray diffraction and UV–visible spectroscopy, respectively. The p-Cu<SUB>4</SUB>O<SUB>3</SUB>/n-ZnO heterojunction diode under dark condition yields rectification behavior with an extremely low saturation current value of 1.8 × 10<SUP>−10</SUP> A and a zero bias photocurrent under illumination condition. The transparent p-Cu<SUB>4</SUB>O<SUB>3</SUB>/n-ZnO heterojunction photodetector can be operated without an external bias, due to the light-induced voltage production. The metal oxide heterojunction based on Cu<SUB>4</SUB>O<SUB>3</SUB>/ZnO would provide a route for the transparent and flexible photoelectric devices, including photodetectors and photovoltaics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> All metal oxide device is proposed for advanced transparent photoelectric devices. </LI> <LI> Transparent metal oxide (p-Cu<SUB>4</SUB>O<SUB>3</SUB>/n-ZnO) device is fabricated room temperature. </LI> <LI> Flexible p-n heterojunction photodetector is operating without a bias. </LI> </UL> </P>

Molecular analysis of mitochondrial cytochrome oxidase I gene of Aedes aegypti L. mosquitoes

Ratnapal Gandhi,Kamlesh K. Yadav,Prabhakargouda B. Patil,Pankaj Bihani,Bharat Char,Shaibal K. Dasgupta,Usha B. Zehr,Shirish R. Barwale 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.1

Aedes aegypti is the most important arboviral vector worldwide. Recent studies reported that genetic variations and gene flow among same mosquito species is responsible for different disease transmission rate. Hence, to understand the relationship between genetic diversity and disease transmission potential, study on genetic variations among mosquito populations is essential. The aim of present study was to investigate the genetic variations of Ae. aegypti targeting COI gene from nine villages of Jalna District, Maharashtra and three laboratory strains originated from Aurangabad, Delhi and transgenic OX513A strain imported from OXITEC, UK. OX513A strain consists of a self-limiting dominant lethal gene construct intended for its use in suppression of Ae. aegypti population by sustained male adult releases in the environment. Mosquito eggs from field and laboratory strains were reared to adults and identified on the basis of morphological characteristics followed by COI gene sequence. Result of MSA and haplotype analysis revealed low genetic variations among field samples and Aurangabad strain, belonged to two haplotypes (H1 and H2) except Ramkheda village represented by separate haplotype H3. Other laboratory DEL strain and transgenic OX513A have great genetic variability to all isolates and have a separate haplotypes H4 and H5. Similar results were observed in phylogenetic analysis. Our observation of phylogenies revealed close relationship among the DEL and transgenic strain OX513A with few Indian and worldwide isolates. The information on genetic variability of mosquito population could help to understand and design the strategies for risk mitigation and effective implementation of new vector control tools like genetically modified mosquitoes.

Optical and electrical properties of Cu-based all oxide semi-transparent photodetector

Kim, Hong-Sik,Patel, Malkeshkumar,Yadav, Pankaj,Kim, Joondong,Sohn, Ahrum,Kim, Dong-Wook American Institute of Physics 2016 Applied Physics Letters Vol.109 No.10

Nano-alumina wrapped carbon microspheres for ultrahigh elimination of pentavalent arsenic and fluoride from potable water

Savan K. Raj,Vartika Sharma,Anshul Yadav,Pankaj D. Indurkar,Vaibhav Kulshrestha 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

Materials with ultrahigh adsorption competences are extensively required for effective wastewaterremediation. Unfortunately, leaching and agglomeration of nanomaterial-based adsorbents is a commonproblem to be resolved. Carbon-based hybrid nanocomposite showing enormous capability in the field ofwastewater treatment. Arsenic and fluoride in water have unpropitious effects on people’s health, andremediation of these ions through adsorption is one of the foremost challenges and high priority tothe research. The present study deals with fabricating a novel composite using alumina wrapped carbonmicrospheres (Al-CMs) with high adsorption capacities and investigating the mechanism for removingpentavalent arsenic/arsenate (As(V)) and fluoride (F) at the molecular level. The maximum adsorptioncapacities for As(V) and F calculated from the Langmuir model are 68 and 371.1 mg/g, respectively, comparativelyhigher than other reported nano-adsorbents. Under optimized conditions, Al-CMs are able toremove more than 98% of F and As(V) under wide range of pH (2–12). Further, the interaction energy ofAl-CMs with F and As(V) was examined using density functional theory (DFT). The reported work exhibitsa feasible adsorbent for removing F and As(V) from the wastewater.

Atypical Radiographic Presentation of Aggressive Vertebral Haemangioma: Experience of Two Cases

Samarth Mittal,Syed Ifthekar,Kaustubh Ahuja,Gagandeep Yadav,Subhajit Maji,Sonal Saran,Pankaj Kandwal 대한척추외과학회 2021 대한척추외과학회지 Vol.28 No.1

Study Design: Case report Objective: We report two cases of vertebral body haemangioma with atypical radiological features causing neurological deficit. Summary of Literature Review: Vertebral haemangiomas are usually asymptomatic and are discovered incidentally during imaging. However, complications such as pain, neurological deficit, vertebral body fracture can arise due to different mechanisms. Materials and Method: We report two cases of vertebral hemangioma of dorsal spine with atypical radiological features. Results: Good pain relief, neurological recovery and functional outcome was achieved by embolization and surgical decompression/ tumor resection along with stabilization in case of aggressive vertebral hemangioma. Aggressive vertebral hemangioma may present with atypical radiographic features. Conclusions: Aggressive vertebral haemangioma may have atypical radiographic presentation. Surgical decompression is one of the preferred treatment of it.

Evaluation of Challenges in Diagnosis of Spontaneous Subacute Pyogenic Spondylodiscitis in Immunocompetent Patients: Experiences from a Tertiary Care Center

Naveen Pandita,Souvik Paul,Gagandeep Yadav,Roop Bhushan Kalia,Pankaj Kandwal 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.4

Study Design: Prospective clinical study. Purpose: We evaluated the challenges faced during diagnosis and management of patients with subacute pyogenic discitis and discussed various clues in clinical history, radiologic and hematologic parameters of these patients that helped in establishing their diagnosis. Overview of Literature: Present literature available shows that in patients with subacute spondylodiscitis and infection with less virulent organisms, the clinical picture often is confusing and the initial radiologic and hematologic studies do not contribute much toward establishing the diagnosis. Methods: Demographic pattern, predisposing factors, clinical presentation, comorbidities, microbiology, treatment, neurologic recovery, and complications of 11 patients were prospectively reviewed regarding their contribution toward the conformation of diagnosis of subacute pyogenic discitis. Results: Mean age at presentation was 46.0 years with average preoperative Oswestry Disability Index and Visual Analog Scale scores of 83.4 and 7.18, respectively. Mean follow-up duration was 12.0 months. The most common site of infection was the lumbar spine, followed by the thoracic spine (n=1). Infective organisms were isolated in only 45% of cases. Staphylococcus aureus was the most common causative organism isolated. Conclusions: Diagnosing subacute spondylodiscitis in a patient presenting with subacute low backache poses a diagnostic challenge. Clinical and radiologic picture are deceiving, and bacteriologic results often are negative, further complicating the picture. A detailed medical history along with clinical, radiologic, and biochemical parameters prevents missing the diagnosis. Serial serum C-reactive protein and alkaline phosphatases were more reliable blood parameters in cases of subacute presentation.