Kulwinder Kaur

Bio: Kulwinder Kaur is an academic researcher from PEC University of Technology. The author has contributed to research in topics: Thermoelectric effect & Thermoelectric materials. The author has an hindex of 21, co-authored 107 publications receiving 1429 citations. Previous affiliations of Kulwinder Kaur include Indian Institute of Technology Ropar & Guru Nanak Dev University.

Strategic review of interface carrier recombination in earth abundant Cu–Zn–Sn–S–Se solar cells: current challenges and future prospects

Abstract: Earth abundant Cu–Zn–Sn–S–Se (CZTSSe) is considered as a promising material for large area and cost effective solar energy harvesting. The current efficiency of CZTSSe champion solar cell, ∼12.7%, is much lower than that of its counterpart Cu–In–Ga–Se (CIGS) solar cell, ∼22.6%, and its theoretically predicted Shockley–Queisser (SQ) limit, ∼32%. This performance disparity is because of a large voltage deficit, ∼0.62 V, in comparison to the optical band gap that primarily results from high carrier recombination at the charge extraction interfaces. The different physical and chemical properties of interfacial layers often cause unfavorable band alignment and interfacial states that lead to high carrier recombination and eventually result in lower device efficiency. To obtain new insights about interfaces and to overcome the interface-related pitfalls, research on interface engineering of solar cells is rapidly accelerating and proven beneficial to achieve better device efficiency. This work provides a detailed strategic review on carrier transport and carrier recombination mechanisms by probing different interfaces of Mo/CZTSSe/CdS/i-ZnO/Al–ZnO/Al through every possible aspect. This review proposes eccentric approaches of carrier management.

Progress and prospects of CZTSSe/CdS interface engineering to combat high open-circuit voltage deficit of kesterite photovoltaics: a critical review

Abstract: CZTSSe solar cells are considered to be potential and cost-effective alternative solutions to mature photovoltaic technology for meeting future energy demands. However, the current performance of CZTSSe solar cells is limited due to their high voltage deficit. The comparison of figure-of-merits of the two technologies show that CZTSSe has 62% lower open circuit voltage compared to that of 35% for CIGS, with respect to their associated band gaps. Efficient charge separation and extraction at the absorber–buffer (p–n) junction is paramount for mitigating the voltage loss and achieve high photo-conversion efficiency. The rapid progress for achieving high deliverables in CZTSSe is impeded by interface recombination, which is a consequence of poor-quality p–n junction. The inherent association of CZTSSe with secondary phases and defects due to narrow phase stability plays an unfavorable role in producing a good quality interface. The high density of interface defects, unfavorable band alignment, and structural inhomogeneities across the interface are some of the leading causes that nurture interface dominant recombination pathways. These interface-related concerns have drawn the scientific community towards interface engineering and modification of the interface to bring closer performance parity between CZTSSe and matured CIGS solar cell technology. Several approaches have attempted to develop favorable interface features that facilitate improved device performance. This work addresses the critical aspects of interface engineering of the absorber–buffer heterojunction in CZTSSe solar cells and the importance of tools that are essential to identify and eradicate the root causes of low efficiency.

Determining Beta Sheet Crystallinity in Fibrous Proteins by Thermal Analysis and Infrared Spectroscopy

Abstract: We report a study of self-assembled beta-pleated sheets in B. mori silk fibroin films using thermal analysis and infrared spectroscopy. B. mori silk fibroin may stand as an exemplar of fibrous proteins containing crystalline beta-sheets. Materials were prepared from concentrated solutions (2−5 wt % fibroin in water) and then dried to achieve a less ordered state without beta-sheets. Crystallization of beta-pleated sheets was effected either by heating the films above the glass transition temperature (Tg) and holding isothermally or by exposure to methanol. The fractions of secondary structural components including random coils, alpha-helices, beta-pleated sheets, turns, and side chains were evaluated using Fourier self-deconvolution (FSD) of the infrared absorbance spectra. The silk fibroin films were studied thermally using temperature-modulated differential scanning calorimetry (TMDSC) to obtain the reversing heat capacity. The increment of the reversing heat capacity ΔCp0(Tg) at the glass transition fo...

Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types

Abstract: A checklist of Recent and fossil catfishes (Order Siluriformes) is presented, summarizing taxonomic literature published through 2005. From 4624 nominal species group names and 810 genus group names, 3093 species are recognized as valid, and are distributed among 478 genera and 36 families. Distributional summaries are provided for each species, and nomenclatural synonymies, including relevant information on all name-bearing types, are included for all taxa. One new name is proposed herein: Clariallabes teugelsi, as a replacement for Clarias (Allabenchelys) dumerili longibarbis David & Poll, 1937, which is preoccupied by Clarias longibarbis Worthington, 1933, but has been treated as a valid species of Clariallabes by Teugels. Acrochordonichthys melanogaster Bleeker, 1854, is designated as type species of Acrochordonichthys Bleeker, 1857, inasmuch as no earlier valid designation has been found. A new genus Pseudobagarius , is proposed for the “ pseudobagarius group” of species formerly placed in Akysis . The status of 228 species group names remains unresolved and 31 names based on otoliths ascribed to catfishes are listed but not placed into the checklist. The current emphasis given to catfish taxonomy at present is likely to result in a dramatic increase in the total number of valid taxa as well as major changes in the membership of some of the higher level taxa recognized here.

Copper-containing mesoporous bioactive glass scaffolds with multifunctional properties of angiogenesis capacity, osteostimulation and antibacterial activity

Abstract: It is of great importance to develop multifunctional bioactive scaffolds, which combine angiogenesis capacity, osteostimulation, and antibacterial properties for regenerating lost bone tissues. In order to achieve this aim, we prepared copper (Cu)-containing mesoporous bioactive glass (Cu-MBG) scaffolds with interconnective large pores (several hundred micrometer) and well-ordered mesopore channels (around 5 nm). Both Cu-MBG scaffolds and their ionic extracts could stimulate hypoxia-inducible factor (HIF)-1a and vascular endothelial growth factor(VEGF) expression in human bone marrow stromal cells(hBMSCs). In addition, both Cu-MBG scaffolds and their ionic extracts significantly promoted the osteogenic differentiation of hBMSCs by improving their bone-related gene expression (alkaline phosphatase (ALP), osteopontin(OPN) and osteocalcin (OCN)). Furthermore, Cu-MBG scaffolds could maintain a sustained release of ibuprofen and significantly inhibited the viability of bacteria. This study indicates that the incorporation of Cu2þ ions into MBG scaffolds significantly enhances hypoxia-like tissue reaction leading to the coupling of angiogenesis and osteogenesis. Cu2þ ions play an important role to offer the multifunctional properties of MBG scaffold system. This study has demonstrated that it is possible to develop multifunctional scaffolds by combining enhanced angiogenesis potential, osteostimulation, and antibacterial properties for the treatment of large bone defects.