Browsing by Author "Saykar, Nilesh G"

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Dual-Functional 3-Acetyl-2,5-dimethylthiophene Additive-Assisted Crystallization Control and Trap State Passivation for High-Performance Perovskite Solar Cells
(American Chemical Society, 2022-11-25T00:00:00) Saykar, Nilesh G; Iqbal, Muzahir; Pawar, Mahendra; Chavan, Kashinath T; Mahapatra, Santosh K
Defect-mediated charge recombination and successive degradation mainly lag the performance of perovskite solar cells (PSCs). Insufficiency or evaporation of organic cations leaves behind the undercoordinated Pb2+ions, which act as severe charge recombination centers. Herein, theoretical and experimental insights into crystallization control and defect passivation of MAPbI3perovskite by the dual-functional 3-acetyl-2,5-dimethylthiophene (ADT) molecule are presented. Density functional theory calculations show that both functional groups of ADT possessing different interaction energies could interact with PbI2. The carbonyl group in ADT shows the dominant interaction with Pb2+forming an intermediate product that might decrease the crystallization rate. Further, the coordinate bonding between ADT and uncoordinated Pb2+ions in perovskite leads to defect passivation. The 0.6% ADT-modified PSCs possess an average power conversion efficiency (PCE) of 18.22 � 0.80% and the highest PCE of 19.03%, whereas the pristine PSCs exhibit an average PCE of 16.23 � 1.32% and the highest PCE of 17.47%. Furthermore, the modified PSCs maintain 80% of the initial PCE up to 650 h during storage at ambient conditions (RH = 35 � 5%). The present study shows that the simultaneous crystalization control and defect passivation achieved via an ADT additive engineering approach could be an efficient strategy to enhance the PCE and stability of PSCs. � 2022 American Chemical Society. All rights reserved.
Impact of Shape (Nanofiller vs. Nanorod) of TiO2 nanoparticle on Free Standing Solid Polymeric Separator for Energy Storage/Conversion Devices
(Wiley, 2018) Arya, Anil; Saykar, Nilesh G; Sharma, Achchhe Lal
We report the investigation on examining the impact of nanofiller (NF)- versus nanorod (NR)-shaped titanium oxide(TiO2) nanoparticle on the structural, electrochemical, transport, thermal, and dielectric properties of the solid polymer electrolyte(SPE). Thin SPEfilms comprising of poly(ethylene oxide), sodium hexafluorophosphate, and dispersed with TiO2NF, TiO2NR (synthe-sized by hydrothermal route) has been prepared via solution cast technique. The shape of nanoparticle influences the morphologicaland structural properties as observed infield emission scanning electron microscope and X-ray diffraction analysis. The highest ionicconductivity was exhibited by the NR dispersed system and is higher than NF dispersed system for all recorded concentration consis-tently. It is attributed to the formation of the long-range conductive path with NR when compared with NF. In addition, the electro-chemical stability window is much higher (~5 V) than the NF-doped system. Furthermore, the dielectric properties of SPE wereinvestigated andfitted in the complete frequency window (1 Hz–1 MHz;T=40–100 C@10 C). It is observed that the NR dispersedsystem shows higher dielectric strength and low relaxation time with respect to NF dispersed system. The results suggest that the NRdispersed SPE possess enhanced properties and is more appropriate for an application in high energy density solid-state Na ion batte-ries.
Synthesis of NiO-Co3O4 nanosheet and its temperature-dependent supercapacitive behavior
(IOPscience, 2018) Saykar, Nilesh G; Pilania, Ritu Kumari; Banerjee, Indrani; Mahapatra,S.K.
A nanosheet of nickel and cobalt double hydroxides (NC RT) has been synthesized by the facile hydrothermal method. It has been treated at temperatures of 300 °C, 400 °C and 500 °C, namely NC 300, NC 400 and NC 500, respectively, to obtain a nanosheet of NiO °Co3O4. Samples have been investigated using XRD, Raman spectroscopy, FESEM and TEM. It can be observed that nickel hydroxide is converted to NiO at 300 °C, whereas cobalt hydroxide is converted to Co3O4 at 400 °C. The double hydroxide nanosheet leads to porous oxide nanosheet at an elevated temperature. The formation of porous structure could be attributed to the rapid release of water molecules during thermal treatment. Four symmetric supercapacitors are prepared with NC RT, NC 300, NC 400 and NC 500 as electrode materials, keeping 3 M KOH as an electrolyte and Whatman filter paper as a separator for all the symmetric supercapacitors. It can be seen that the specific capacitances of the NC RT, NC 300, NC 400 and NC 500 symmetric supercapacitors are decreased with increasing temperature in the range of 25 °C °80 °C and scan rate in the range of 10 °500 mV s−1. It can be seen that the NC 300 has excellent supercapacitive behavior. The specific capacitance of NC RT decreased from 20 to 6 F g−1, NC 300 decreased from 324 to 57 F g−1, NC 400 decreased from 132 to 61 F g−1 and NC 500 decreased from 81 to 48 F g−1 with the variation of scan rate from 10 °500 mV −1. The decrement in the specific capacitance may be attributed to the increased bulk and charge transfer resistance at elevated temperature.