GROWTH OF K 2 CO 3 -DOPED KDP CRYSTAL FROM AN AQUEOUS SOLUTION AND AN INVESTIGATION OF ITS PHYSICAL PROPERTIES RAST KDP KRISTALOV Z DODATKOM K 2 CO 3 IZ VODNE RAZTOPINE IN PREISKAVA NJIHOVIH FIZIKALNIH LASTNOSTI

In this present work, KDP and 2M%-K2CO3-doped KDP crystals were grown by a slow-evaporation solution technique. The grown crystals were characterized by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray diffractometry (XRD), UV-Vis spectroscopy, and laser damage threshold (LDT) analysis. The presence of the functional groups of the grown crystals was identified from the FT-IR spectra. The XRD tests showed that the grown crystals had a tetragonal structure. A comparison of the optical transmission of the grown crystals revealed that the K2CO3-doped KDP crystal had a higher transmission than the pure KDP crystal for the entire UV and visible region. Keywords: growth from solution, slow-evaporation solution technique, KDP crystal, K2CO3 additive V predstavljenem delu so KDP in z 2M % K2CO3 dopirani KDP kristali rasli s tehniko po~asnega izhlapevanja teko~ine. Dobljeni kristali so bili karakterizirani iz infrarde~o spektroskopijo s Fourierjevo transformacijo (FT-IR), z rentgensko difrakcijo (XRD), z UV-Vis spektroskopijo in s pragom po{kodbe z laserjem (LDT). Prisotnost funkcionalnih skupin kristalov v rasti je bila dolo~ena s FT-IR spektrom. XRD je pokazal, da imajo rasto~i kristali tetragonalno zgradbo. Primerjava prepustnosti svetlobe v rasto~ih kristalih je odkrila, da imajo KDP kristali, dopirani s K2CO3, bolj{o prepustnost kot pa~isti KDP v celotnem UV in v vidnem podro~ju. Klju~ne besede: rast iz raztopine, tehnika po~asnega izparevanja raztopine, KDP kristal, dodatek K2CO

The physical and electrochromic properties of Prussian Blue thin films electrodeposited on ITO electrodes

In this article, a set of Prussian Blue (PB) thin films with different electrodeposition times (25 s, 50 s, 75 s, 100 s and 150 s) in air at ambient temperature was prepared. The layers were characterized by a variety of techniques which include, field effect scanning electron microscopy, energy-dispersive X-ray spectrometer, X-ray diffraction, Fourier transform infared spectroscopy, UV-Vis spectrophotometry, and electrochemical analysis. A simple and exact electrochemical method was used to estimate the optimal voltages for coloring and bleaching of different PB layers. Controlling electrodeposition time along with applying suitable voltage enabled us to investigate and improve electrochromic properties of PB layer. The sample prepared under 75 s deposition time showed probably a composition intermediate between the insoluble and soluble form. Furthermore, this sample (S75) shows a better electrochromic properties. High value of electrochromic contrast 55.36% at 555 nm and well stability of ion exchange by cycling are the characteristics of this layer. The control of the deposition time resulted in an increase of 9.38 times of the contrast ratio and corresponding values for optical density (Delta OD) of the PB layers.The authors also acknowledgement FEDER, through COMPETE and Fundacao para a Ciencia e a Tecnologia (FCT) Pest-OE/QUI/UI0616/2014 and the project LUMECD (POCI-01-0145-FEDER-016884)

Growth and characterization of TGS single crystal doped with NiSO4 grown by Sankaranarayanan-Ramasamy method

Unidirectional <001> NiSO4 doped triglycine sulphate (TGS) single crystal of 15 mm in diameter and 150 mm in length was successfully grown in aqueous solution by Sankaranarayanan-Ramasamy (S-R) method. The characterization of the grown crystal was made by powder X-ray diffraction, UV-Vis. spectroscopy, Fourier transform infrared spectroscopy (FTIR), Vicker’s microhardness studies. The X-ray diffraction analysis revealed a monoclinic structure for the grown crystal. UV–Vis. analysis showed high transmittance for the doped TGS crystal in the entire visible region. FTIR spectrum verified the presence of various functional groups in the grown specimen. Vicker's microhardness studies of the doped TGS crystal showed that it is harder than pure TGS crystal. The density of the doped crystal was found to be higher than that of the undoped one

Gellan-gum and LiTFSI-Based solid polymer electrolytes for electrochromic devices

It has been long recognized that solid polymer electrolytes (SPEs) are potentially interesting for solid-state electrochemical devices. Gellan gum (Ge)-based SPEs, plasticized with glycerol (Gly) and doped with lithium bis(trifluoromethanesulfone)imide (LiTFSI) were prepared by the solvent casting technique, and their properties were evaluated. LiTFSI-based SPE systems exhibit, on the average, higher conductivities than similar systems with other lithium salts. The structure, morphology, complex impedance spectroscopy, cyclic voltammetry and thermal stability of the new electrolyte system were characterized. Electrochromic devices (ECDs) were built with optimized electrolyte samples and their performance was analyzed. The samples were applied in small ECDs with glass/ITO/CeO2-TiO2/SPE/Prussian blue/ITO/glass configuration. The devices presented a two-modulation operation: a semi-bright mode (-2.5 V) and a dark mode (+0.5 V). The best results were obtained with the ECD containing the GeGly(1)Li(2.4) electrolyte, for which the transmittance (T) values in the bleached and colored states were ca. 33.4/43.0 % and 5.4/8.8 % at 555/1000 nm, respectively. These results correspond to Delta T and Delta OD values of 28.0/34.2 % and 0.79/0.69, respectively, which give quite high CEin and CEout values of -4925 cm(2) C-1 for bleaching (Q(in)=-272.1 mu C cm(-2)), and 2062 cm(2) C-1 for coloring (Q(out)=650.0 mu C cm(-2)), at 630 nm. This electro-optical performance suggests that the proposed SPE systems are promising materials to be further investigated and applied in ECDs.The authors are grateful to FundacAo para a Ciencia e a Tecnologia (FCT) under contracts, UID/QUI/00686/2020, UIDB/00616/2020 and UIDP/00616/2020. V. B. Isfahani acknowledges a Post-Doc grant from the project NORTE-01-0145-FEDER-028538. R.F.P. Pereira thanks FCT-UM for the contracts in the scope of Decreto-Lei 57/2016 and 57/2017. M. Fernandes acknowledges FCT-UTAD for the contract in the scope of Decreto-Lei 57/2016 and Lei 57/2017. A. Pawlicka acknowledges The Brazilian National Council for Scientific and Technological Development (CNPq) for grant 307429/2017-2 and R. C. Sabadini acknowledges "CoordenacAo de Aperfeicoamento de Pessoal de Nivel Superior" (CAPES) for grant 88881.172281/2018-01