Dr Nimai Mishra, Assistant Professor, Department of Chemistry, SRM University-AP along with his team comprising of his PhD scholars Mr. Syed Akhil, Ms. V.G.Vasavi Dutt, and Mr Rahul Singh have published a research article titled “Surface-State-Mediated Interfacial Hole Transfer Dynamics Between CsPbBr3 Perovskite Nanocrystals and Phenothiazine Redox Couple” in The Journal of Physical Chemistry-C, published by The American Chemical Society with an impact factor of ~4.126.

Dr Mishra’s research interests lie in Semiconductor nanocrystals, Core/shell branched structures, Nanowires, Perovskite nanocrystals and Optoelectronic device fabrication. He studied the role of surface chemistry for improving excited state hole transfer from CsPbBr3 nanocrystals to an acceptor, potentially applicable for photocatalytic applications.

About the research:

Recently, caesium lead bromide (CsPbBr3) perovskite nanocrystals (PNCs) gained enormous attention for designing photocatalytic reactions because of their photocatalytic properties. But the surface chemistry of nanocrystals is often ignored which dictate the excited state interactions of these semiconductor nanocrystals with the charge shuttling redox-active molecules. In this work, we have explored the impact of CsPbBr3 perovskite nanocrystals with the three different surface chemistries on the excited state interactions with the standard hole acceptor phenothiazine molecule. From the steady PL-lifetime decay measurements we have calculated the photoinduced hole transfer (PHT). In the amine-free PNCs case, PHT is 6 times higher than the conventional amine capped ligands. Using the lifetime fast component (1) rate constants, we have calculated the hole transfer constant (kht) which is 3.942 × 108 s-1 and it is 4 times higher in amine-free ligands when compared with conventional amine ligands system.

According to Dr Nimai Mishra, the most important contribution of this research is that these results highlight the impact of surface chemistry on the excited state interactions of CsPbBr3 PNCs and conclude amine-free PNCs could be an ideal candidate for photocatalytic reactions.

Read the full paper: https://pubs.acs.org/doi/10.1021/acs.jpcc.1c07129

Swikriti Khadke, Pragya Gupta, and Shanmukh Rachakunta from third-year Computer Science Engineering have published a research paper titled “Efficient Plastic Recycling and Remold Circular Economy using the Technology of Trust – Blockchain” along with their mentors from SRM University-AP Dr Jatindra Kumar Dash, Dr Goutam Kumar Dalapati and Dr Sabyasachi Chakrabortty in the peer-reviewed journal Sustainability.

Global plastic waste is increasing rapidly. The strategic management of plastic waste and recycling can preserve environmental species and associated costs. The utilization of plastic can be done by introducing Blockchain during plastic waste recycling. Automation for the segregation and collection of plastic waste can effectively establish a globally recognizable tool using Blockchain-based applications. Collection and sorting of plastic recycling are feasible by keeping track of plastic with unique codes or digital badges throughout the supply chain. Efficient recycling technology is essential to reduce plastic pollution. Many technologies have been employed to enhance plastic recycling. Among them, blockchain is promising for plastic recycling and circular economy (CE). Blockchain, a distributed ledger, consists of some ordered blocks which are unchangeable. This can be considered an exemplary way to push the transactions of their customers under the same blockchain technology. The research group used machine learning techniques to predict plastic generation globally so that they could see the impact it will make in the coming future. The students have used ARIMA – Auto-Regressive Integrated Moving Average for the study.

The potential idea is to utilize an approach wherein recyclers can keep track of generated waste as it moves through the various chains. A platform that works by tracking recycling activities across a local recycling supply chain on the Blockchain. When this will be publicly available, consumers can also use the ledger info to make more informed purchasing decisions. The Blockchain can be utilized to track individual items through the recycling supply chain by creating physical markers like QR codes.

The suggested Blockchain-based platform can be implemented in various nations with an autonomous waste collector and storage system. This process can be expanded to individual collectors and storage systems. The novel process will be created by incorporating a reward-based Blockchain scheme with the collaboration of global businesses and local waste collectors. The proposed model further allows the effective sharing of databases among various supply chains to create a CE.

Talking about the social implications of the research, the students firmly believe that the study will result in the introduction of new technology in the recycling industry and promote awareness about technology in rural areas. Developing a platform and implementing blockchain and other facilities will be the focus of these young innovative brains of SRM University-AP in the forthcoming days.

Read the full paper here: https://doi.org/10.3390/su13169142

Dr Nimai Mishra, Assistant Professor, Department of Chemistry, SRM University-AP, Andhra Pradesh, along with his research group comprising of students pursuing PhD under him, Ms V.G.Vasavi Dutt and Mr Syed Akhil has published a research article titled Cesium Lead Bromide Perovskite Nanocrystals as a Simple and Portable Spectrochemical Probe for Rapid Detection of Chlorides in the Journal ChemistrySelect (Publisher: Wiley-VCH on behalf of Chemistry Europe, Impact Factor-2.2).

Chloride anions are widely abundant in water and when they combine with calcium, potassium, and magnesium, they form chloride salts. However, the higher concentrations badly affect the environment by causing severe dehydration and even plant death. High concentrations of sodium chloride exhibit the potential of corrosive damage thereby releasing toxic metals from plumbing fixtures. Hence, there is a need to monitor the concentration levels of chloride salts in water. Several techniques like titration, spectrophotometry, ion chromatography, electrochemistry, etc have been reported to date. Despite the high accuracy and precision of these techniques, they involve expensive instrumentation and is out of reach from on-site detection. Hence, it is necessary to look for simple, portable, and cost-effective strategies for the detection of chlorides in the water.

In this article, Dr Mishra’s research group demonstrated that the wide spectral tunability of CsPbBr3 perovskite nanocrystals (NCs) via instantaneous and facile anion exchange, make them a suitable candidate for chloride detection. Rapid anion-exchange processes between CsPbBr3 perovskite NCs and different chloride solutions were carried out in ambient conditions. The resultant anion-exchanged CsPbCl3-xBrx NCs preserved the structural properties and exhibited a remarkable blue shift in photoluminescence spectra. This forms a basis for the detection of chloride ions in water. This has been applied with the limit of detection up to 100 µM. The detection strategies were not only limited to the direct addition of chloride solutions to NCs, but they also showed a visual colour change under UV light when the chloride solution is drop-casted on CsPbBr3 films that are deposited on glass substrates. Furthermore, the detection strategy is established by drop-casting CsPbBr3 NCs onto paper strips that are pre-soaked in chloride solutions. A considerable blue shift in fluorimetry proves them to be an excellent sensing medium as practical spectrochemical probes for on-site detection of chlorides. Based on this, a colour chart and selectivity chart to access the presence of chlorides and their concentration is also demonstrated.

Read the full paper here

An interactive session between Prof U Ramamurty, President Chair Professor, School of Mechanical & Aerospace Engineering at Nanyang Technological University (NTU), Singapore, and the faculty members of SRM University – AP, Andhra-Pradesh was held on Monday.

During the discussion, Prof Ramamurty emphasized the importance of research collaboration between faculty members from different research areas and about utilizing expertise to achieve significant scientific output.

Dr Pardhasaradhi Maram from the Department of Chemistry, Dr Sabyasachi Mukhopadhyay from the Department of Physics, and Prof G S Vinod Kumar from the Department of Mechanical Engineering presented their detailed research areas that focus on storage devices, catalysts for value-added products, energy and sensing devices, novel metallic materials, additive manufacturing of metals and Bio-implants, and industry collaborative research work.

Prof Ramamurty said that he is glad to see that productive science is being done at SRM University-AP. “Given that the University has started only 4 years ago and been functioning amidst a pandemic for more than one and a half years, the progress in research is significant and very impressive. Interdisciplinary efforts between various departments in the University will give effective results”, he added.

Prof D Narayana Rao, Pro-Vice-Chancellor, SRM University – AP expressed his interest in establishing NTU – SRM joint Centre for Advanced Research in functional and structural materials at SRM University campus to Prof Ramamurty. The centre that Prof Rao envisions will provide an opportunity to synergize the expertise and resources of NTU, Singapore, and SRM University – AP to carry out front-line research in the areas of novel materials, self-healing materials and also additive manufacturing (3D Printing of metals and bio-implants).