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Thin films of delafossites of ␣-AgGaO 2 were prepared on ␣-Al 2 O 3 ͑0001͒ and on Si ͑100͒ single crystal substrates by pulsed laser deposition. The films have a band gap of 4.12 eV and a transparency of more than 50% in the visible region. The electrical conductivity at 300 K was 3.2ϫ 10 −4 S cm −1 . The positive sign of Seebeck coefficient ͑+70 V K −1 ͒ demonstrated the p-type conduction in the films. Transparent p-n heterojunctions on a glass substrate having a structure glass/ITO/ n-ZnO / p-AgGaO 2 were fabricated. The ratio of forward to reverse current was more than 100 in the range of −2 to + 2 V.

Liquid phase exfoliation of Ti3C2Tx MXene using LiF/HCl mix, forming HF in situ, has been modified by the addition of NH4OH. The base assisted dilution and extraction of MXene enables a quick control over pH and improves the structural, morphological and optical properties of the compound. The formation of a buffer compound NH4F, reduces the oxidation on the surface of MXene and etches off the residual MAX phase, by attacking Al. The structural features of the prepared NH4OH added Ti3C2Tx MXene are remarkably better than the HF etched samples, with the characteristic MXene peak in XRD being emphasized in the former. The addition of ammonia solution improves the milder in situ HF etching technique, by giving the characteristic open accordion structure to the compound, making the compound easy to delaminate and more stable against oxidation in ambient atmosphere.

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A novel lead free nano fibers of Cesium Titanium Bromide (CsTiBr3) perovskite is synthesized on commercial glass substrate by a two stage deposition method for the first time. Cesium Bromide thin film prepared by vacuum evaporation by resistive heating is the substrate for deposition of Titanium Bromide (TiBr4) vapor by an in-house deposition arrangement. The duration of deposition of TiBr4 vapor on CsBr thin film plays a key role on the structural, compositional and morphological properties of CsTiBr3. The mechanism behind the formation of nano fibers of CsTiBr3 from polygonal grains of CsBr is discussed in detail. The grain boundary grooving of CsBr polygonal grains influences the evolution and dimension of CsTiBr3 nano fibers. The nano fiber structure and lead free nature makes this novel perovskite a promising candidate for sensors, nanolasers and for future nanoelectronics.