Benzoyl peroxide (BPO) is generally considered as first line treatment against acne. Low water solubility and formation of larger clusters and limited skin permeation upon topical application necessitates the application of high amount of drug for desired action which leads to induction of skin irritation. In the present study, we developed BPO-loaded niosomal formulation to improve its permeation through skin. The niosomes were further loaded in the carbopol gel to improve contact time. The results of the skin permeation study, skin retention study revealed that niosomes can effectively improve the drug permeation through skin. Application of niosomal gel significantly reduced the bacterial load after a treatment of four days. This reduction in bacterial load was further resulted in a significant reduction in the inflammation with minimal skin irritation compared with plain drug and the plain niosomal formulation.

Owing to the high thermoelectric (TE) conversion efficiency, low cost, and environmental friendliness Mg 2 Si 0.3 Sn 0.7 solid solution has emerged as the material of choice for the n-leg of a TE generator for midtemperature (room temperature to 800 K) applications. Dimensionless TE figure-of-merit (ZT) values of 1.3 (at 700 K) have been reported in this compound when optimally doped. High ZT values in this compound are due to a combination of improved electrical properties (band convergence effect) and reduced lattice thermal conductivity (alloy scattering of phonons). Here we demonstrate that the TE performance in this solid solution can be improved further (ZT max = 1.7 at T = 673 K, which is a record in silicide-based TE materials) by enhancing phonon scattering with embedded nanoprecipitates. The high ZT values are obtained when Mg 2 Si 0.3 Sn 0.7 is codoped with Bi and Cr. While Bi helps in optimizing the electrical transport properties, Cr results in formation of nanoprecipitates. Transmission electron microscopy (TEM) studies indicate embedded nanoprecipitates rich in elemental Cr and Sn. The nanoprecipitates also result in a strained interface as confirmed from high-resolution TEM (HRTEM) and grazing incidence XRD (GIXRD) studies. This results in an ∼15% reduction in the lattice thermal conductivity (κ L ) compared to the only Bi-doped sample while retaining similar power factor (S 2 σ) values. The overall effect is a ZT eng value of 0.73, which corresponds to a conversion efficiency (η) of 12% with the cold side temperature of 323 K and a ΔT = 350 K.

Thermoelectric (TE) generators enable the direct and reversible conversion between heat and electricity, providing applications in both refrigeration and power generation. In the last decade, several TE materials with relatively high figures of merit (zT) have been reported in the low‐ and high‐temperature regimes. However, there is an urgent demand for high‐performance TE materials working in the mid‐temperature range (400–700 K). Herein, p‐type AgSbTe2 materials stabilized with S and Se co‐doping are demonstrated to exhibit an outstanding maximum figure of merit (zTmax) of 2.3 at 673 K and an average figure of merit (zTave) of 1.59 over the wide temperature range of 300–673 K. This exceptional performance arises from an enhanced carrier density resulting from a higher concentration of silver vacancies, a vastly improved Seebeck coefficient enabled by the flattening of the valence band maximum and the inhibited formation of n‐type Ag2Te, and ahighly improved stability beyond 673 K. The optimized material is used to fabricate a single‐leg device with efficiencies up to 13.3% and a unicouple TE device reaching energy conversion efficiencies up to 12.3% at a temperature difference of 370 K. These results highlight an effective strategy to engineer high‐performance TE material in the mid‐temperature range.

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Metallization (known as contacting) of thermoelectric (TE) legs is vital to the long-term performance of a TE device. It is often observed that the compositional changes in a TE solid solution may render a given contact material unsuitable due to a mismatch in the thermal expansion coefficient values. Finding suitable contact materials for TE solid solutions (which often are the best TE materials) remains a challenge. In this work, we propose a multilayer single-step approach in which the same combination of contact materials can be used for a wide compositional range in a solid solution. The outer layer is a metal foil, which helps in creating an Ohmic contact with the interconnects. The intermediate layer is a mixture of the TE material and a metal powder, which results in the formation of the diffusion barrier. The innermost layer is the TE material, which is the active component of the device. The strategy was applied on n- and p-doped Mg2Si0.3Sn0.7 with elemental Cu and Ni providing the desired interface functionalities. Single-step compaction was carried out using the monoblock sintering technique. Microscopic investigation reveals the formation of a well-bonded crack-free interface. Various intermetallic phases were identified at the interface, and the formation of the MgNi2Sn phase was found to be critical to prevent any interdiffusion of elements. Electrical contact resistance (r c) measurements were conducted, and low values of 3 and 19 μΩ cm2 were measured in n- and p-type legs, respectively. The contacted TE legs were further annealed at 400 °C for 7 days to check their stability. Microstructural and electrical resistance measurements reveal minimal changes in the interface layer and r c values, indicating the workability of the multilayer technique.

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Mg2Si specimens doped with Bi, Al, and Se are synthesized via induction melting followed by rapid compaction using an induction assisted hot‐uniaxial press. Phase formation, dopant solubility, and microstructure are studied using X‐Ray diffraction and scanning electron microscopy. Results indicate the presence of the dopants to varying extent in the Mg2Si matrix, which is reflected in the lattice parameter and charge carrier concentration values. Temperature dependent thermoelectric properties are measured between room temperature and 673 K. Se is observed to enhance the density of states (DOS) effective mass (mnormalD*), while Al increased the carrier mobility (μ). Best thermoelectric performance are obtained for co‐doped Bi,Se and Bi,Al compositions with ≈20% increase in engineering figure of merit, ZTeng (ΔT = 350 K) compared to only Bi doped specimen. This enhancement can be explained from the observed electronic (increased mnormalD* due to Se incorporation) and microstructural (μ increase in Al containing compositions due to lower grain boundary magnesium oxide layer)characteristics of the specimens. Also, grain boundary accumulation (of Bi) is observed in Bi doped samples which results in a lowering of the lattice thermal conductivity, κnormalL.