@article {49552, title = {Investigating the visible range photoresponse of an organic single-crystal analogue of the green fluorescent protein}, journal = {Nanoscale}, volume = {17}, year = {2025}, month = {APR}, pages = {8614-8623}, type = {Article}, abstract = {

The growing demand for lightweight, flexible, semi-transparent and low-cost photodetectors (PDs) in wearable electronics and optical communication systems has prompted studies to investigate organic materials as feasible alternatives to conventional inorganic PDs. However, modern organic PDs often face responsivity, detectivity, and photoresponse speed limitations, particularly in the visible range. Here, we present the photoresponse of an organic single-crystal analogue of the green fluorescent protein (GFP) chromophore photodetector, fabricated on a silicon nitride substrate. A significant increase in photocurrent was detected upon illumination with visible wavelengths (532 nm, 630 nm, and halogen light). A remarkably consistent and repeatable photoresponse was obtained during the ON and OFF illumination cycles. The device showed the dependence of photocurrent on the applied bias voltages. The measured photocurrent, responsivity, detectivity, rise time, decay time, noise equivalent power and external quantum efficiency are studied for different wavelengths. Strikingly, the fabricated device demonstrates excellent performance in the visible region compared to several conventional organic and inorganic PDs. The observed responsivity and detectivity values for the device are 98 mA W-1 and 7.94 x 108 Jones, respectively. Furthermore, the device also exhibits rapid photoresponse dynamics with a rise time of 180 ms and a decay time of 152 ms. The excellent photodetection features indicate that the single crystal GFP could serve as a versatile broadband material for future applications in optoelectronics.

}, issn = {2040-3364}, doi = {10.1039/d4nr05252h}, author = {Virole, Vishal and Dabke, Niteen and Verma, Sahil and Kumar, Ajay and Pandya, Rinu and Husale, Sudhir and Vanka, Kumar and Gonnade, Rajesh and Kanawade, Rajesh} } @article {49882, title = {Optimisation of metallic bismuth nanoparticle supported Pt-Bi(x\%)/C hybrid electrocatalyst for cost effective and efficient hydrogen production in alkaline media}, journal = {International Journal of Hydrogen Energy}, volume = {161}, year = {2025}, month = {AUG}, pages = {150699}, type = {Article}, abstract = {

The present study employed a simple mechanochemical method followed by 24-h ultrasonication to synthesize oxide-free metallic bismuth (Bi) nanoparticles. This was further used to synthesize a Pt-Bi(x\%)/C (NC-x) hybrid electrocatalyst for the hydrogen evolution reaction in alkaline media. X-ray photoelectron spectroscopy and contact angle measurements reveal, Bi modifies the electronic structure and surface morphology of the Pt/C electrocatalyst, thus enhancing reaction kinetics and active site availability. The relative three-electrode study reveals that optimised NC-20 electrocatalyst reduces the overpotentials by 10.44 \% and enhances the current density by 53 \% compared to commercial Pt/C. The practical applicability of the NC-20 electrocatalyst was studied with the 13 cm2 single cell anion exchange membrane electrolyser. The catalyst demonstrates promising performance where the current density of NC-20//IrO2 relatively increases by 22.6 \% compared to standard Pt/ C//IrO2, and shows continuous production and stable performance when monitored for 30 h.

}, keywords = {AEM, Bismuth nanoparticles, electrocatalyst, Full cell electrolysis, hydrogen evolution reaction, water electrolysis}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2025.150699}, author = {Dokhe, Revati and Ugale, Atul and Dube, Onkar and Varpe, Vaibhav and Galave, Chaitanya and Hattale, Gangadhar and Kadam, Rutuja and Virole, Vishal and Kumar, Ajay and Husale, Sudhir and Natu, Varun and Shevate, Rahul and Kanawade, Rajesh} } @article {49954, title = {Photoluminescence decay lifetime study of hydrothermally synthesized highly porous ruthenium-silica composite for optical dissolved oxygen sensing application}, journal = {ACS Applied Nano Materials}, volume = {9}, year = {2026}, month = {JAN}, pages = {937-949}, type = {Article}, abstract = {

Pore size and surface area of photoluminescence (PL)-based transition metal composites play crucial roles in facilitating oxygen diffusion, thereby enhancing the response and sensitivity of optical dissolved oxygen (DO) sensors. In this study, we successfully applied the hydrothermal method to synthesize a porous ruthenium composite embedded in a silica matrix, demonstrating its effectiveness for optical DO sensing applications. The ruthenium-silica (Ru-Si) composites were synthesized using Ru(bpy)3 2+ and tetraethyl orthosilicate (TEOS) as precursors, with reaction temperatures ranging from 120 degrees C to 200 degrees C over a fixed duration of 4 h. The structural, morphological, and compositional characterization techniques confirmed the successful synthesis and evaluated the porosity, surface features, and chemical structure of the resulting composites. The optimized Ru-Si composite exhibited the highest porosity, characterized by a specific surface area of 996.78 m2 g- 1, and exhibited the highest decay lifetime of 8.14 mu s in deionized (DI) water, compared to other composites. Importantly, we demonstrate an excellent linear response of the synthesized Ru-Si composite to DO concentrations ranging from 2.58 to 11.16 mg L-1, with a Stern-Volmer constant of 0.12. Furthermore, a density functional theory study was conducted to investigate the electronic transitions and to elucidate the oxygen quenching mechanism of the excited Ru composite with molecular oxygen. The calculated photophysical parameters of the composite show good agreement with the experimental results. Preliminary results suggest that the synthesized Ru-Si with high pore size and surface area could be an efficient and effective composite for use in DO sensing applications.

}, keywords = {Hydrothermal method, opticalDO sensor, oxygen quenching, photoluminescent, ruthenium composite}, doi = {10.1021/acsanm.5c04307}, author = {Hattale, Gangadhar and Kadam, Rutuja and Virole, Vishal and Pandya, Rinu and Paul, Aditya and Kumar, Ajay and Shevate, Rahul and Vanka, Kumar and Saha, Avishek and Kanawade, Rajesh} } @article {50050, title = {Polysulfone-based polymer carbon dot membrane for optical dissolved oxygen sensing application}, journal = {Chemistry-An Asian Journal}, volume = {21}, year = {2026}, month = {MAR}, pages = {e70685}, type = {Article}, abstract = {

The precise monitoring of dissolved oxygen (DO) is essential across industrial, environmental, and biomedical applications. However, the state-of-the-art DO sensing methods often suffer from inherent limitations, which hinder their effectiveness for real-time and long-term DO monitoring. Optical DO sensing, despite its advantages, utilizes expensive metal complexes and is prone to photobleaching and slow response time. Here, we introduce a novel polymer carbon dot (PCD) as a promising candidate for lifetime-based optical DO sensing. The PCD is a metal-free, nontoxic, fluorescent, long decay-lifetime material that is synthesized through hydrothermal method. Our fluorescent PCD exhibits high emission quantum yield (24.32\%), long decay-lifetime (10.43 \& micro;s), and a linear response to DO concentrations ranging from 0.7 to 12.7 mg/L, with a Stern-Volmer constant of 0.1115. Further, to obtain better oxygen diffusion, high porosity, optical transparency, and high flexibility, PCD was embedded into a polysulfone matrix (PSF_PCD). The PSF_PCD membrane shows better results for the decay lifetime (9.4 \& micro;s), surface energy (40.26 mN/m), and average pore diameter of 5 nm. Hence, the obtained results demonstrate the applicability of the PCD in optical DO sensors for real-time and long-term monitoring of DO levels.

}, keywords = {decay lifetime, dissolved oxygen, Hydrothermal method, polymer carbon dots, polysulfone-based membrane}, issn = {1861-4728}, doi = {10.1002/asia.70685}, author = {Kadam, Rutuja and Hattale, Gangadhar and Virole, Vishal and Pal, Sanjivani and Abraham, Athira and Paul, Aditya and Kumar, Ajay and Shevate, Rahul and Banpurkar, Arun and Kanawade, Rajesh and Saha, Avishek} }