Browsing by Author "Ankit Kumar Srivastava"

Now showing 1 - 3 of 3

Lysosome-targeting solid state NIR emissive donor-acceptor molecules: a study on photophysical modulation through architectural distinction
(Royal Society of Chemistry, 2024) Ashish Kumar Kushwaha; Ankit Kumar Srivastava; Pradeep Kumar; Anjani Kumar; Saripella Srikrishna; Roop Shikha Singh
The prevalence of the D-A strategy in achieving red-shifted emission has been established through designing D-A molecules of D-A-D and A-D-A constructs. Architectural control over such D-A systems integrates solid state NIR emission with lysosome tracking and sets a multifarious goal of photophysical modulation in a comprehensive way. In particular, two compounds, CPM-1 (D-A-D) and CPM-2 (A-D-A), have been synthesized by introducing carbazole-based donors and difluoroboron acceptors. Lysosome targeting and imaging have been achieved through incorporation of a morpholine unit, which ultimately imparts viscosity sensitivity to the construct. The fluorophores exhibited significant emission in solution along with distinctive solvatochromism, viscochromism and TICT. A comparative account of these competitive photophysical properties revealed the superior charge transfer properties of the A-D-A construct (CPM-2), while the D-A-D molecule (CPM-1) was found to be a better molecular rotor with marked viscochromism. The solid state NIR emission has been found to be much more intense in CPM-1 relative to CPM-2, which further highlights the influence of structural aspects on photophysical behvaiour. Theoretical studies further established the distinctive characteristics of ground and excited states in these compounds. Owing to its excellent viscochromic behvaiour, CPM-1 has been successfully utilized in lysosome targeting in wild-type Drosophila fly gut tissues through co-localization studies. © 2024 The Royal Society of Chemistry.
Mechanochromism and aggregation-induced emission directed by donor strength in quinoxaline-based D-A molecules with application in latent fingerprinting and inkless writing
(Royal Society of Chemistry, 2025) S. Dasaratha Kumar; Ankit Kumar Srivastava; Ashish Kumar Kushwaha; Anjani Kumar; Roop Shikha Singh
The molecular structure influences essential properties such as photoluminescence, charge transfer, and mechanical responsiveness, directly impacting material performance in optoelectronics, sensing, and bioimaging. The present work is a systematic effort to develop three organic molecules (QPA1, QPA2 and QPA3) having a donor-acceptor construct, wherein the charge transfer (CT) states were augmented with an aggregation-induced emission (AIE) effect. The synthesized molecules feature an aminophenyl group as the donor and formylated quinoxaline core as the acceptor. The variations in the donor strength on the aminophenyl core, from -H (QPA1) and -Me (QPA2) to -Ph (QPA3), profoundly and intricately modulated the AIE attribute as well as the CT states. QPA1 turns out to be an aggregation-caused quenching (ACQ) fluorophore, while QPA2 and QPA3 behave as AIEgens, with QPA3 showing superior efficiency. Furthermore, the charge transfer properties are modulated by donor strength, with QPA3 demonstrating a more pronounced intramolecular charge transfer response. QPA1-QPA3 molecules have significant solid-state emission and have shown mechanofluorochromic (MFC) behaviour in response to mechanical stress. The MFC response varies with the change in substituents. The excellent AIE activity of QPA3 has enabled its exploration for latent fingerprinting with three levels of detailing. The good contrast and brightness in the solid-state emission of QPA1 and QPA3 were further utilized for inkless writing application. © 2025 The Royal Society of Chemistry.
Smart sensing solutions for the growth of agriculture
(Elsevier, 2024) Ankit Kumar Srivastava; Swasti Saxena; Surendra K. Yadav; Prashasti Ashok
The global population is growing suddenly, and resources are being used up quickly. We need creativity, especially in agriculture, to feed such a vast population. The most technologically advanced and demanding industry now is agriculture. There is a serious concern about how quickly the condition of the land is declining. We must apply contemporary agricultural assistance to end hunger, improve the farmer's financial situation, and so directly enhance the financial situation of the nation. One of the buzzwords of the moment is "precision farming" or "smart farming," and with the development of technology, particularly in the areas of Internet of Things and artificial intelligence, agriculture is reaching new heights. The creation of various uses and sensors for farming growth is greatly aided by IoT and sensor networks. This motivates us to offer the classification of various smart sensing applications and breakthroughs in agriculture. We will discuss a variety of sensors in this chapter that will be useful in forestry and agriculture. © 2024 Elsevier Inc. All rights reserved.