The National Institute for Interdisciplinary Science and Technology (NIIST, formerly Regional Research Laboratory, Trivandrum) is a constituent laboratory of CSIR, India, engaged in research and development activities in the field of agroprocessing and technology, microbial processes and technology, chemical sciences and technology, material sciences and technology and process engineering and environmental technology. Around approximately 80 scientists and 300 research fellows are working in various scientific disciplines in this institute. The programmes have a blend of basic research, technology development and commercialization; have specific thrusts on frontier areas of research, National Mission Projects, regional resource-based activities and R & D - Industry - Academia linkages. The laboratory has excellent collaborative programmes with major National & International agencies too. the present director of the institute is Dr. A. Ajayaghosh.It was established in 1975 as a CSIR Complex, then named as the Regional Research Laboratory in 1978 and later renamed as NIIST in 2007.
Single-atom palladium nanoclusters (Pd-SA NCs) anchored on boron carbon nitride (BCN-Pd) were rationally constructed via an in situ thermal polymerization-impregnation strategy, yielding atomically dispersed Pd sites at an ultralow metal loading (0.39 wt %). Advanced structural characterization (EXAFS, XANES, and HRTEM) confirms the predominance of isolated Pd centers coordinated with C/N environments, along with highly dispersed Pd nanocluster features, establishing a catalytically versatile Pd-C-N interfacial structure. The BCN-Pd catalyst exhibits dual functionality, efficiently promoting both nitroarene hydrogenation and base-free aminocarbonylation reactions. Notably, oxalic acid dihydrate is employed as a safe, inexpensive, and environmentally benign CO surrogate, eliminating the need for hazardous gaseous CO. The catalyst delivers excellent activity and selectivity (>98% yield) under mild conditions, significantly reducing noble metal consumption while maintaining high catalytic efficiency. In addition to suppressing metal waste, the system demonstrates outstanding stability and recyclability, outperforming conventional Pd catalysts. Density functional theory (DFT) calculations elucidate the aminocarbonylation mechanism and reveal a strong correlation between theoretical predictions and experimental observations. Overall, this work establishes BCN-supported Pd single-atom architectures as an effective and sustainable catalytic platform for the synthesis of pharmaceutically relevant molecules.
GeTe-based degenerate semiconductors offer a promising platform for thermoelectric optimization owing to their responsive electronic structure and intrinsically low lattice thermal conductivity. However, neither the pure rhombohedral nor the pure cubic GeTe phase offers optimal band degeneracy for maximizing the thermoelectric power factor. Here, we demonstrate that defect-engineered co-doping enables simultaneous control of crystal symmetry and thereby electronic band structure in GeTe. Cr substitution suppresses the rhombohedral phase fraction and induces valence band convergence, leading to an enhanced m(DOS)* and nearly 35% increase in the power factor (53 mu W cm(-1) K-2) at 750 K, while excessive Cr (3.5%) destabilizes the rhombohedral phase. Temperature-dependent synchrotron x-ray diffraction further elucidates the role of Cr in lowering the onset temperature of cubic symmetry (similar to 663 K). A simple two-band phenomenological model incorporating the L-Sigma valence-band offset offers a transparent framework to rationalize the contrasting thermopower evolution in GeTe as compared to 2.5% Cr doped GeTe. In contrast, Se substitution stabilizes the rhombohedral lattice and suppresses the bipolar activation of minority carriers. Specifically, 2% Cr, 5% Se co-doped GeTe exhibits significant suppression of bipolar transport in the high-temperature thermoelectric transport. Ultraviolet photoelectron spectroscopy reveals a deeper Fermi level and increased work function upon Se incorporation, consistent with an increased minority carrier activation energy. These results establish defect-engineered co-doping as an effective strategy to couple phase evolution with valence band convergence, enabling enhanced thermoelectric performance in GeTe across abroad temperature range.
Polymer aerogels with inherent electron-donating or-accepting tendencies hold great promise for triboelectric nanogenerators (TENGs). However, conventional fabrication of polymer aerogels often involves complex processes and the use of cross-linking agents to ensure structural stability. Moreover, most research has primarily focused on enhancing the tribo-negative nature of polymer aerogels, with limited attention to improving the electron-donating characteristics, which is an essential factor for optimizing triboelectric performance. In this study, we have rationally fabricated a highly tribo-positive nylon-11 aerogel using unidirectional freeze casting. This method yields anisotropic nylon-11 aerogels with aligned crystalline domains, which modulate surface functional groups, enhance surface polarity, and improve charge transfer efficiency during contact-electrification. When paired with a tribo-negative PVDF layer, the anisotropic nylon-11 aerogel exhibited a peak-to-peak output voltage (Vpp) of 277 Vpp, outperforming the 228 Vpp generated by its isotropic counterpart. To further amplify the tribo-positive performance, we incorporated silk nanofibrils (SNFs) derived from natural silkworm cocoons. The addition of 10 wt% SNFs significantly enhanced the surface polarity, leading to a remarkable increase in output voltage to 650 Vpp and a maximum peak power density of 1 W/m2. This work presents an effective and scalable route to engineer tribo-positive aerogels, providing a significant advancement in the design of high-performance TENG materials and expanding their applicability in self-powered electronics.
Abstract Ordered assembly of fullerenes is of significant importance in organic electronic applications, as charge carrier mobility in fullerene-based materials is highly sensitive to structural order. However, commonly employed solution-processing techniques often suffer from strong aggregation tendencies or uncontrolled crystallization of fullerenes during film formation. In contrast, advanced nanofabrication techniques that enable precise control over fullerene morphology at the nanoscale are typically complex and costly. In this work, we propose a facile supramolecular strategy based on the polymer-assisted assembly of a pyridinium-functionalized fullerene amphiphile (FPy) to achieve ordered fullerene architectures, thereby enhancing charge carrier mobility through reduced energetic disorder. A commercially available anionic polymer, polystyrenesulfonate (PSS), was employed to assemble the cationic fullerene derivative (FPy) primarily via electrostatic interactions, further stabilized by π–π stacking between fullerene units. The interaction of FPy with PSS was confirmed by UV–visible absorption spectroscopy, while TEM, SEM, and AFM analyses revealed the formation of ultrathin two-dimensional crystalline nanosheets with highly ordered fullerene packing. X-ray diffraction (XRD) analyses clearly demonstrate a transition from polycrystalline FPy to a highly ordered and uniform face-centered cubic (FCC) lattice in the PSS/FPy hybrid, confirming the anionic polymer-induced switching toward a more ordered nanoassembly. Space-charge-limited current (SCLC) measurements further revealed an order-of-magnitude enhancement in electron mobility (0.92 × 10–3 cm2 V–1 S–1) compared to FPy alone, which can be correlated with the reduced energetic disorder in the FCC lattice structure of the PSS/FPy hybrid assembly. Overall, this study highlights the significance of polymer-assisted assembly of rationally designed amphiphilic fullerenes as a general and scalable strategy to improve electron transport in a wide range of optoelectronic devices.
