scispace - formally typeset
Search or ask a question
Author

Trilok Singh

Bio: Trilok Singh is an academic researcher from Indian Institute of Technology Bombay. The author has contributed to research in topics: Slope stability & Rock mass classification. The author has an hindex of 54, co-authored 373 publications receiving 10286 citations. Previous affiliations of Trilok Singh include Indian Institute of Technology Delhi & University of Cologne.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a method to reproduce stable and high power conversion efficiency (PCE) of a triple cation perovskite prepared using a one-step solution deposition and low-temperature annealing fully conducted in controlled ambient humidity conditions was explored.
Abstract: Perovskite solar cells have evolved to have compatible high efficiency and stability by employing mixed cation/halide type perovskite crystals as pinhole-free large grain absorbers. The cesium (Cs)–formamidium–methylammonium triple cation-based perovskite device fabricated in a glove box enables reproducible high-voltage performance. This study explores the method to reproduce stable and high power conversion efficiency (PCE) of a triple cation perovskite prepared using a one-step solution deposition and low-temperature annealing fully conducted in controlled ambient humidity conditions. Optimizing the perovskite grain size by Cs concentration and solution processes, a route is created to obtain highly uniform, pinhole-free large grain perovskite films that work with reproducible PCE up to 20.8% and high preservation stability without cell encapsulation for more than 18 weeks. This study further investigates the light intensity characteristics of open-circuit voltage (Voc) of small (5 × 5 mm2, PCE > 20%) and large (10 × 10 mm2, PCE of 18%) devices. Intensity dependence of Voc shows an ideality factor in the range of 1.7-1.9 for both devices, implying that the triple cation perovskite involves trap-assisted recombination loss at the hetero junction interfaces that influences Voc. Despite relatively high ideality factor, perovskite device is capable of supplying high power conversion efficiency under low light intensity (0.01 Sun) whereas maintaining Voc over 0.9 V.

424 citations

Journal ArticleDOI
01 Jan 2012
TL;DR: The neuro fuzzy system is applied to predict the rock Young's modulus to overcome the limitation of ANN and fuzzy logic and endow with high performance of predictive neuro-fuzzy system to make use for prediction of complex rock parameter.
Abstract: The engineering properties of the rocks have the most vital role in planning of rock excavation and construction for optimum utilization of earth resources with greater safety and least damage to surroundings. The design and construction of structure is influenced by physico-mechanical properties of rock mass. Young's modulus provides insight about the magnitude and characteristic of the rock mass deformation due to change in stress field. The determination of the Young's modulus in laboratory is very time consuming and costly. Therefore, basic rock properties like point load, density and water absorption have been used to predict the Young's modulus. Point load, density and water absorption can be easily determined in field as well as laboratory and are pertinent properties to characterize a rock mass. The artificial neural network (ANN), fuzzy inference system (FIS) and neuro fuzzy are promising techniques which have proven to be very reliable in recent years. In, present study, neuro fuzzy system is applied to predict the rock Young's modulus to overcome the limitation of ANN and fuzzy logic. Total 85 dataset were used for training the network and 10 dataset for testing and validation of network rules. The network performance indices correlation coefficient, mean absolute percentage error (MAPE), root mean square error (RMSE), and variance account for (VAF) are found to be 0.6643, 7.583, 6.799, and 91.95 respectively, which endow with high performance of predictive neuro-fuzzy system to make use for prediction of complex rock parameter.

339 citations

Journal ArticleDOI
TL;DR: In this article, an attempt has been made to evaluate and predict the blast-induced ground vibration and frequency by incorporating rock properties, blast design and explosive parameters using the artificial neural network (ANN) technique.

336 citations

Journal ArticleDOI
TL;DR: In this article, the mechanical properties of one igneous, three sedimentary and three metamorphic rock types were determined in the laboratory and correlated with P-wave velocity, which may avoid the necessity for time-consuming and tedious laboratory testing.
Abstract: Impact strength index, slake durability index and uniaxial compressive strength (UCS) are important properties of a rock mass which are used widely in geological and geotechnical engineering. In this study, the mechanical properties of one igneous, three sedimentary and three metamorphic rock types were determined in the laboratory and correlated with P-wave velocity. Empirical equations have been developed to predict the impact strength index, slake durability index and UCS from P-wave velocity, which may avoid the necessity for time-consuming and tedious laboratory testing. To check the sensitivity of the empirical relations, a t test was performed which confirmed the validity of the proposed correlations.

296 citations

Journal ArticleDOI
TL;DR: The optical measurements showed a strong absorption band around 500 nm, and the devices made on anatase TiO2 mesoporous layer showed good performance with current density over 0.8 mA cm(-2), while the devices on brookiteTiO2 layer and planar (free of porous layer) was inefficient.
Abstract: Methylammonium iodo bismuthate ((CH3NH3)3Bi2I9) (MBI) perovskite is a promising alternative to rapidly progressing hybrid organic–inorganic lead perovskites because of its better stability and low toxicity compared to lead-based perovskites. Solution-processed perovskite fabricated by single-step spin-coating and subsequent heating produced polycrystalline films of hybrid perovskite (CH3NH3)3Bi2I9), whose morphology was influenced drastically by the nature of substrates. The optical measurements showed a strong absorption band around 500 nm. The devices made on anatase TiO2 mesoporous layer showed good performance with current density over 0.8 mA cm–2 while the devices on brookite TiO2 layer and planar (free of porous layer) was inefficient. However, all the MBI devices were stable to ambient conditions for more than 10 weeks.

260 citations


Cited by
More filters
Journal ArticleDOI
17 Feb 2017-Science
TL;DR: A contact-passivation strategy using chlorine-capped TiO2 colloidal nanocrystal film that mitigates interfacial recombination and improves interface binding in low-temperature planar solar cells is reported.
Abstract: Planar perovskite solar cells (PSCs) made entirely via solution processing at low temperatures (<150°C) offer promise for simple manufacturing, compatibility with flexible substrates, and perovskite-based tandem devices. However, these PSCs require an electron-selective layer that performs well with similar processing. We report a contact-passivation strategy using chlorine-capped TiO2 colloidal nanocrystal film that mitigates interfacial recombination and improves interface binding in low-temperature planar solar cells. We fabricated solar cells with certified efficiencies of 20.1 and 19.5% for active areas of 0.049 and 1.1 square centimeters, respectively, achieved via low-temperature solution processing. Solar cells with efficiency greater than 20% retained 90% (97% after dark recovery) of their initial performance after 500 hours of continuous room-temperature operation at their maximum power point under 1-sun illumination (where 1 sun is defined as the standard illumination at AM1.5, or 1 kilowatt/square meter).

1,912 citations

Journal ArticleDOI
TL;DR: The fundamentals, recent research progress, present status, and views on future prospects of perovskite-based photovoltaics, with discussions focused on strategies to improve both intrinsic and extrinsic (environmental) stabilities of high-efficiency devices are described.
Abstract: The photovoltaics of organic–inorganic lead halide perovskite materials have shown rapid improvements in solar cell performance, surpassing the top efficiency of semiconductor compounds such as CdTe and CIGS (copper indium gallium selenide) used in solar cells in just about a decade. Perovskite preparation via simple and inexpensive solution processes demonstrates the immense potential of this thin-film solar cell technology to become a low-cost alternative to the presently commercially available photovoltaic technologies. Significant developments in almost all aspects of perovskite solar cells and discoveries of some fascinating properties of such hybrid perovskites have been made recently. This Review describes the fundamentals, recent research progress, present status, and our views on future prospects of perovskite-based photovoltaics, with discussions focused on strategies to improve both intrinsic and extrinsic (environmental) stabilities of high-efficiency devices. Strategies and challenges regardi...

1,720 citations

Journal ArticleDOI
TL;DR: A state-of-the-art literature survey is conducted to taxonomize the research on TOPSIS applications and methodologies and suggests a framework for future attempts in this area for academic researchers and practitioners.
Abstract: Multi-Criteria Decision Aid (MCDA) or Multi-Criteria Decision Making (MCDM) methods have received much attention from researchers and practitioners in evaluating, assessing and ranking alternatives across diverse industries. Among numerous MCDA/MCDM methods developed to solve real-world decision problems, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) continues to work satisfactorily across different application areas. In this paper, we conduct a state-of-the-art literature survey to taxonomize the research on TOPSIS applications and methodologies. The classification scheme for this review contains 266 scholarly papers from 103 journals since the year 2000, separated into nine application areas: (1) Supply Chain Management and Logistics, (2) Design, Engineering and Manufacturing Systems, (3) Business and Marketing Management, (4) Health, Safety and Environment Management, (5) Human Resources Management, (6) Energy Management, (7) Chemical Engineering, (8) Water Resources Management and (9) Other topics. Scholarly papers in the TOPSIS discipline are further interpreted based on (1) publication year, (2) publication journal, (3) authors' nationality and (4) other methods combined or compared with TOPSIS. We end our review paper with recommendations for future research in TOPSIS decision-making that is both forward-looking and practically oriented. This paper provides useful insights into the TOPSIS method and suggests a framework for future attempts in this area for academic researchers and practitioners.

1,571 citations

11 Jun 2010
Abstract: The validity of the cubic law for laminar flow of fluids through open fractures consisting of parallel planar plates has been established by others over a wide range of conditions with apertures ranging down to a minimum of 0.2 µm. The law may be given in simplified form by Q/Δh = C(2b)3, where Q is the flow rate, Δh is the difference in hydraulic head, C is a constant that depends on the flow geometry and fluid properties, and 2b is the fracture aperture. The validity of this law for flow in a closed fracture where the surfaces are in contact and the aperture is being decreased under stress has been investigated at room temperature by using homogeneous samples of granite, basalt, and marble. Tension fractures were artificially induced, and the laboratory setup used radial as well as straight flow geometries. Apertures ranged from 250 down to 4µm, which was the minimum size that could be attained under a normal stress of 20 MPa. The cubic law was found to be valid whether the fracture surfaces were held open or were being closed under stress, and the results are not dependent on rock type. Permeability was uniquely defined by fracture aperture and was independent of the stress history used in these investigations. The effects of deviations from the ideal parallel plate concept only cause an apparent reduction in flow and may be incorporated into the cubic law by replacing C by C/ƒ. The factor ƒ varied from 1.04 to 1.65 in these investigations. The model of a fracture that is being closed under normal stress is visualized as being controlled by the strength of the asperities that are in contact. These contact areas are able to withstand significant stresses while maintaining space for fluids to continue to flow as the fracture aperture decreases. The controlling factor is the magnitude of the aperture, and since flow depends on (2b)3, a slight change in aperture evidently can easily dominate any other change in the geometry of the flow field. Thus one does not see any noticeable shift in the correlations of our experimental results in passing from a condition where the fracture surfaces were held open to one where the surfaces were being closed under stress.

1,557 citations

01 Apr 2016
TL;DR: The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964.
Abstract: Time is divided by geologists according to marked shifts in Earth's state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Here we review the historical genesis of the idea and assess anthropogenic signatures in the geological record against the formal requirements for the recognition of a new epoch. The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964. The formal establishment of an Anthropocene Epoch would mark a fundamental change in the relationship between humans and the Earth system.

1,173 citations