Indian Institute of Technology Indore

About: Indian Institute of Technology Indore is a education organization based out in Indore, Madhya Pradesh, India. It is known for research contribution in the topics: Computer science & Chemistry. The organization has 1606 authors who have published 4803 publications receiving 66500 citations.

Carbazole-Based Spiro[fluorene-9,9'-xanthene] as an Efficient Hole-Transporting Material for Perovskite Solar Cells.

Abstract: For the practical application of perovskite solar cells (PSC), it is desirable to have high efficiency, long-term stability, and low manufacturing cost. Therefore, it is required to develop inexpensive and well-performing hole-transporting materials (HTMs). In this study, we synthesized SFXDAnCBZ, which is a new carbazole-based spiro[fluorene-9,9'-xanthene] (SFX) derivative, where the central core and end-cap units consist of SFX and N3,N6-bis(di-4-anisylamino)-9H-carbazole (DAnCBZ), respectively, as an efficient and low-cost HTM for PSCs. Photoluminescence quenching at the SFXDAnCBZ/perovskite interface was more effective than at the perovskite/Spiro-OMeTAD (2,2',7,7'-tetrakis-(N,N-di-p-methoxy-phenyl-amine) 9,9'spiro-bifluorene) interface. We fabricated a PSC with a power conversion efficiency (PCE) of 20.87% under 1 sun illumination (100 mW cm-2) using SFXDAnCBZ as an HTM. This value is comparable to that measured for the benchmark Spiro-OMeTAD. Thus, this result confirms that SFX core-based materials can be a new kind of HTMs for high-efficiency and low-cost PSCs.

Design of Time---Frequency Optimal Three-Band Wavelet Filter Banks with Unit Sobolev Regularity Using Frequency Domain Sampling

Abstract: In this paper, we design three-band time---frequency-localized orthogonal wavelet filter banks having single vanishing moment. We propose new expressions to compute mean and variances in time and frequency from the samples of the Fourier transform of the asymmetric band-pass compactly supported wavelet functions. We determine discrete-time filter of length eight that generates the time---frequency optimal time-limited scaling and wavelet functions using cascade algorithm. Time---frequency product (TFP) of a function is defined as the product of its time variance and frequency variance. The TFP of the designed functions is close to 0.25 with unit Sobolev regularity. Three-band filter banks are designed by minimizing a weighted combination of TFPs of wavelets and scaling functions. Interestingly, empirical results show that time---frequency optimal, filter banks of length nine, designed with the proposed methodology, have unit Sobolev regularity, which is maximum achievable with single vanishing moment. Design examples for length six and length nine filter banks are given to demonstrate the effectiveness of the proposed design methodology.

Understanding the climate change impact on crop yield over Eastern Himalayan Region: ascertaining GCM and scenario uncertainty

Abstract: It is well established that the adverse impact of climate change is going to affect every aspect of the ecosystem in the hilly terrain of the Himalayan region. Therefore, it is inevitable to assess the climate change impact on crop yield over the hilly terrain to undertake sustainable adaptation and agricultural practices. In the present study, Sikkim is considered as a study area, and crop simulation for three different crops (rice, wheat and maize) is carried out using calibrated AquaCrop with an available baseline dataset of 17 years (1998–2015). The future projections of different crop yields are obtained by using bias-corrected climate scenarios from four different global climate models (GCMs) under two different emission scenarios. Moreover, the uncertainty associated with the GCM and emission scenario is examined through the possibility theory. The outcomes from the simulations indicate an increase in the mean percentage change in the yield (0.5% to 20% for rice, 2% to 44% for wheat and 10% to 25% for maize) over Sikkim during 2021–2099. The increase in the mean yield can be attributed to the suitable temperature profile, increase in the CO2 concentration, high elevation of the study area and no significant water stress during the growing seasons of different crops and using the possibility approach indicates that during the recent past (2006–2015), the stabilized scenario is prevailing over the high emission scenarios in most of the cases. Our results facilitate the water and agricultural manager for considering proper and robust adaptation measures to ensure sustainability.

Localized surface plasmon resonance on Au nanoparticles: tuning and exploitation for performance enhancement in ultrathin photovoltaics

Abstract: We report a detailed correlation analysis of the size, shape, and distribution of Au nanoparticles (NPs) on fine-tuning of localized surface plasmon resonance and optical absorption cross-section. Experimental analysis of annealing temperature and initial Au layer thickness on NP parameters such as size, interparticle distance, surface coverage, and circularity factor has been studied. The effect of annealing on the morphological, structural, dielectric, and elemental behavior of Au NPs has been reported. Theoretically, we have analyzed the tuning of LSPR and absorption cross-section peaks by varying NP parameters, surrounding medium, and substrate. This report is critical in terms of predicting performance enhancement of ultrathin photovoltaics with varied cell architectures.