Efficient planar n-i-p type heterojunction flexible perovskite solar cells with sputtered TiO2electron transporting layers

Mali, Sawanta S.,Hong, Chang Kook,Inamdar, A. I.,Im, Hyunsik,Shim, Sang Eun The Royal Society of Chemistry 2017 Nanoscale Vol.9 No.9

<P>The development of hybrid organo-lead trihalide perovskite solar cells (PSCs) comprising an electron transporting layer (ETL), a perovskite light absorber and a hole transporting layer (HTL) has received significant attention for their potential in efficient PSCs. However, the preparation of a compact and uniform ETL and the formation of a uniform light absorber layer suffer from a high temperature processing treatment and the formation of unwanted perovskite islands, respectively. A low temperature/room temperature processed ETL is one of the best options for the fabrication of flexible PSCs. In the present work, we report the implementation of a room temperature processed compact TiO2 ETL and the synthesis of extremely uniform flexible planar PSCs based on methylammonium lead mixed halides MAPb (I-1-(X) Br-x)(3) (x = 0.1) via RF-magnetron sputtering and a toluene dripping treatment, respectively. The compact TiO2 ETLs with different thicknesses (30 to 100 nm) were directly deposited on a flexible PET coated ITO substrate by varying the RF-sputtering time and used for the fabrication of flexible PSCs. The photovoltaic properties revealed that flexible PSC performance is strongly dependent on the TiO2 ETL thickness. The open circuit voltage (V-OC) and fill factor (FF) are directly proportional to the TiO2 ETL thickness while the 50 nm thick TiO2 ETL shows the highest current density (J(SC)) of 20.77 mA cm(-2). Our controlled results reveal that the room temperature RF-magnetron sputtered 50 nm-thick TiO2 ETL photoelectrode exhibits a power conversion efficiency (PCE) in excess of 15%. The use of room temperature synthesis of the compact TiO2 ETL by RF magnetron sputtering results in an enhancement of the device performance for cells prepared on flexible substrates. The champion flexible planar PSC based on this architecture exhibited a promising power conversion efficiency as high as 15.88%, featuring a high FF of 0.69 and V-OC of 1.108 V with a negligible hysteresis under AM 1.5 G illumination. Furthermore, the mechanical bending stability revealed that the fabricated devices show stable PCE up to 200 bending cycles. The interface properties revealed that the 50 nm thick TiO2 ETL provides superior charge injection characteristics and low internal resistance. The present work provides a simplistic and reliable approach for the fabrication of highly efficient stable flexible perovskite solar cells.</P>

Solvothermal synthesis of high-performance Ni-Co layered double hydroxide nanofoam electrode for electrochemical energy storage

Patel, R.,Inamdar, A.I.,Hou, B.,Cha, S.,Ansari, A.T.,Gunjakar, J.L.,Im, H.,Kim, H. ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.4

<P>A nanofoam nickel cobalt layered double hydroxide (NiCo(OH)(2)) electrode film is fabricated on a stainless-steel substrate with the use of a simple one-step solvothermal process. The nanofoam NiCo(OH)(2) electrode exhibits a high specific capacitance of 2710.2 Fig at a current density.of 9.1 A/g, and a good capacity retention of similar to 70% after 2000 charge-discharge cycles at a high current density of 31.8 A/g. An energy density of 60.23 Wh/kg is obtained at a power density of 1.8 kW/kg. The excellent electrochemical energy storage performance of the NiCo(OH)(2) electrode is due to the synergetic effect of a significantly improved ionic diffusion and an effective charge transfer, which is linked to a well-dispersed interconnected nanofoam morphology and binder-free direct contact with the current collector. (C) 2017 Elsevier B.V. All rights reserved.</P>

Calcium nitrate (Ca(NO₃)₂)-based inorganic salt electrode for supercapacitor with long-cycle life performance

Cho, S.,Han, J.,Kim, J.,Jo, Y.,Woo, H.,Lee, S.,Aqueel Ahmed, A.T.,Chavan, H.C.,Pawar, S.M.,Gunjakar, J.L.,Kwak, J.,Park, Y.,Inamdar, A.I.,Kim, H.,Kim, H.,Im, H. ELSEVIER 2017 CURRENT APPLIED PHYSICS Vol.17 No.9

<P>A novel water-soluble inorganic Ca(NO3)(2) salt electrode is investigated for its pseudocapacitance in an aqueous KOH electrolyte. Commercially available Ca(NO3)(2) salt is directly used as the key electrode material. The supercapacitor electrode contains Ca(NO3)(2) salt, carbon black, and polyvinylidene fluoride (PVDF) in a ratio of 80:10:10. The Ca(NO3)(2)-based electrode demonstrates an exceptionally long life cycling stability, and a reasonably sound specific capacitance of 234 F/g is obtained at a current density of 3 A/g. Via chemical and electrochemical reactions, the in-situ activation of the Ca(NO3)(2) forms an intermediate CaO which contributes to the pseudocapacitance of the electrode. The electrode undergoes a reversible redox reaction between Cu2+ <-> Cu+ during the charge-discharge process. Superior rate capability and excellent specific capacitance retention of similar to 120% over 2000 cycles are achieved compared with other inorganic salt electrodes. (C) 2017 Elsevier B.V. All rights reserved.</P>

Facile electrodeposition of high-density CuCo2O4 nanosheets as a high-performance Li-ion battery anode material

S.M. Pawar,B.S. Pawar,Bo Hou,A.T.A. Ahmed,H.S. Chavan,조용철,조상근,김종민,서지우,차승남,A. I. Inamdar,김형상,임현식 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

High-density CuCo2O4 nanosheets are grown on Ni foam using electrodeposition followed by airannealing for a Li-ion battery anode. The anode exhibits a high discharge capacity of 1244 mAh/g at 0.1 A/g (82% coulombic efficiency) and excellent high-rate performance with 95% capacity retention(1100 mAh/g after 200 cycles at 1 A/g). The outstanding battery performance of the CuCo2O4 anode isattributed to its binder-free direct contact to the current collector and high-density nanosheetmorphology. The present experimentalfindings demonstrate that the electrodeposited binder-freeCuCo2O4 material may serve as a safe, low-cost, long-cycle life anode for Li-ion batteries.

Synthesis and enhanced electrochemical supercapacitive properties of manganese oxide nanoflake electrodes

Inamdar, A.I.,Jo, Y.,Kim, J.,Han, J.,Pawar, S.M.,Kalubarme, R.S.,Park, C.J.,Hong, J.P.,Park, Y.S.,Jung, W.,Kim, H.,Im, Hyunsik Elsevier 2015 ENERGY Vol.83 No.-

<P><B>Abstract</B></P> <P>MnO<SUB>2+δ</SUB> (Manganese oxide) nanoflakes were synthesized for use as electrode material in electrochemical supercapacitors. The nanoflakes were produced via RF-magnetron sputtering with various excess oxygen contents (δ), and the electrochemical supercapacitive properties of the MnO<SUB>2+δ</SUB> nanoflakes were investigated as a function of δ with the use of a Na<SUB>2</SUB>SO<SUB>4</SUB> electrolyte. The excess oxygen (δ) induces the MnO<SUB>2+δ</SUB> nanoflakes to form a thin open structure, and μ-Raman measurements revealed that the MnO<SUB>2+δ</SUB> nanoflakes formed a birnessite phase with a layered structure. X-ray photoelectron spectroscopy was used to obtain quantitative information on both the oxidation state and the chemical composition of the nanoflake electrodes. The crystallinity of the nanoflakes improved when the oxygen partial pressure increased during sputtering. At an optimal δ ∼ 0.6, the electrochemical stability and the capacity retention significantly improved, and electrochemical impedance spectroscopy revealed that easy access of Na<SUP>+</SUP> ions into the nanoflakes at an optimal δ value resulted in a low diffusion resistance, playing a key role in determining the improvement in the supercapacitor characteristics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MnO<SUB>2+δ</SUB> nanoflakes are grown using RF-magnetron sputtering. </LI> <LI> Excess oxygen (δ) endorses the formation of a porous and open structure. </LI> <LI> At δ ∼ 0.6, the stability and capacity retention are significantly improved. </LI> <LI> Low diffusion resistance plays a key role in determining supercapacitor characteristics. </LI> </UL> </P>

Direct growth of 2D nickel hydroxide nanosheets intercalated with polyoxovanadate anions as a binder-free supercapacitor electrode

Gunjakar, Jayavant L.,Inamdar, Akbar I.,Hou, Bo,Cha, SeungNam,Pawar, S. M.,Abu Talha, A. A.,Chavan, Harish S.,Kim, Jongmin,Cho, Sangeun,Lee, Seongwoo,Jo, Yongcheol,Kim, Hyungsang,Im, Hyunsik The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.19

<P>A mesoporous nanoplate network of two-dimensional (2D) layered nickel hydroxide Ni(OH)2 intercalated with polyoxovanadate anions (Ni(OH)2-POV) was built using a chemical solution deposition method. This approach will provide high flexibility for controlling the chemical composition and the pore structure of the resulting Ni(OH)2-POV nanohybrids. The layer-by-layer ordered growth of the Ni(OH)2-POV is demonstrated by powder X-ray diffraction and cross-sectional high-resolution transmission electron microscopy. The random growth of the intercalated Ni(OH)2-POV nanohybrids leads to the formation of an interconnected network morphology with a highly porous stacking structure whose porosity is controlled by changing the ratio of Ni(OH)2 and POV. The lateral size and thickness of the Ni(OH)2-POV nanoplates are ∼400 nm and from ∼5 nm to 7 nm, respectively. The obtained thin films are highly active electrochemical capacitor electrodes with a maximum specific capacity of 1440 F g<SUP>−1</SUP> at a current density of 1 A g<SUP>−1</SUP>, and they withstand up to 2000 cycles with a capacity retention of 85%. The superior electrochemical performance of the Ni(OH)2-POV nanohybrids is attributed to the expanded mesoporous surface area and the intercalation of the POV anions. The experimental findings highlight the outstanding electrochemical functionality of the 2D Ni(OH)2-POV nanoplate network that will provide a facile route for the synthesis of low-dimensional hybrid nanomaterials for a highly active supercapacitor electrode.</P>

Synthesis of Cu₂ZnSnS₄ (CZTS) absorber by rapid thermal processing (RTP) sulfurization of stacked metallic precursor films for solar cell applications

Pawar, S.M.,Inamdar, A.I.,Pawar, B.S.,Gurav, K.V.,Shin, S.W.,Yanjun, Xiao,Kolekar, S.S.,Lee, Jung-Ho,Kim, Jin Hyeok,Im, Hyunsik Elsevier 2014 Materials Letters Vol.118 No.-

<P><B>Abstract</B></P> <P>Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> (CZTS) absorbers have been grown on Mo-coated glass substrates by the rapid thermal processing (RTP) sulfurization of stacked metallic precursor (CZT) films at different annealing temperatures ranging from 500 to 580°C for 5min in sulfur atmosphere. The effects of sulfurization temperature on the structural, morphological, chemical, and optical properties of the CZTS absorbers have been investigated. XRD and Raman studies reveal that the as-deposited stacked metallic precursor films consist of metal elements such as Zn, Sn and binary alloys such as Cu<SUB>6</SUB>Sn<SUB>5</SUB>, Cu<SUB>3</SUB>Sn and CuZn. The sulfurized CZTS absorber films have single phase polycrystalline kesterite crystal structure with dense morphology. At 580°C, the CZT metallic precursor film is fully sulfurized with Zn-rich and Sn-poor composition, and its bandgap energy is found to be 1.50eV. The solar cell fabricated with the CZTS absorber grown at an optimized sulfurization temperature of 580°C shows a conversion efficiency of ~5% for a 0.44cm<SUP>2</SUP> area with <I>V</I> <SUB> <I>oc</I> </SUB>=561mV, <I>J</I> <SUB> <I>sc</I> </SUB>=18.4mA/cm<SUP>2</SUP>, and <I>FF</I>=48.2.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Single phase Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> is synthesized by rapid thermal processing sulfurization. </LI> <LI> Higher annealing temperature improves the crystallinity of Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> absorber. </LI> <LI> Cu<SUB>2</SUB>ZnSnS<SUB>4</SUB> absorber is fully sulfurized at 580°C. </LI> <LI> A solar cell with a ~5% conversion efficiency is demonstrated. </LI> </UL> </P>

Facile electrodeposition of high-density CuCo₂O₄ nanosheets as a high-performance Li-ion battery anode material

Pawar, S.M.,Pawar, B.S.,Hou, Bo,Ahmed, A.T.A.,Chavan, H.S.,Jo, Yongcheol,Cho, Sangeun,Kim, Jongmin,Seo, Jiwoo,Cha, SeungNam,Inamdar, A.I.,Kim, Hyungsang,Im, Hyunsik Elsevier 2019 Journal of industrial and engineering chemistry Vol.69 No.-

<P><B>Abstract</B></P> <P>High-density CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets are grown on Ni foam using electrodeposition followed by air annealing for a Li-ion battery anode. The anode exhibits a high discharge capacity of 1244mAh/g at 0.1A/g (82% coulombic efficiency) and excellent high-rate performance with 95% capacity retention (1100mAh/g after 200 cycles at 1A/g). The outstanding battery performance of the CuCo<SUB>2</SUB>O<SUB>4</SUB> anode is attributed to its binder-free direct contact to the current collector and high-density nanosheet morphology. The present experimental findings demonstrate that the electrodeposited binder-free CuCo<SUB>2</SUB>O<SUB>4</SUB> material may serve as a safe, low-cost, long-cycle life anode for Li-ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Synthesis of high-density CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets via electrodeposition method. </LI> <LI> CuCo<SUB>2</SUB>O<SUB>4</SUB> nanosheet electrode exhibits a high discharge capacity of 1244mAh/g at 0.1A/g. </LI> <LI> Excellent rate capability and stability with 95% capacity retention after 200 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Bendable RuO₂/graphene thin film for fully flexible supercapacitor electrodes with superior stability

Cho, Sangeun,Kim, Jongmin,Jo, Yongcheol,Ahmed, Abu Talha Aqueel,Chavan, H.S.,Woo, Hyeonseok,Inamdar, A.I.,Gunjakar, J.L.,Pawar, S.M.,Park, Youngsin,Kim, Hyungsang,Im, Hyunsik ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.725 No.-

<P><B>Abstract</B></P> <P>Ruthenium oxide (RuO<SUB>2</SUB>) is fabricated on graphene (Gr)-coated Copper (Cu) foil by using a cathodic electroplating technique for flexible supercapacitor electrode applications. The electrochemical properties of the RuO<SUB>2</SUB>/Gr/Cu electrode are investigated with a conventional three electrode configuration in 0.5 M H<SUB>2</SUB>SO<SUB>4</SUB> electrolyte. The graphene insertion layer plays a key role in improving the structural and electrochemical properties of the RuO<SUB>2</SUB> electrode film under the bent condition. The electrode exhibits a specific capacitance of 1561 F g<SUP>−1</SUP> (0.015 F cm<SUP>−1</SUP>) at a scan rate of 5 mV s<SUP>−1</SUP> and a significantly improved retention of 98% under the bent condition. The flexible RuO<SUB>2</SUB>/Gr/Cu electrode exhibits a high energy density of ∼13 Wh kg<SUP>−1</SUP> at a power density of ∼21 kW kg<SUP>−1</SUP>. The excellent capacitance retention and electrochemical stability of the flexible RuO<SUB>2</SUB>/Gr/Cu electrode are due to the improved mechanical adhesion between the RuO<SUB>2</SUB> and the current collector. This flexible RuO<SUB>2</SUB>/Gr/Cu film could be used as a supercapacitor electrode with a high capacity and long-cycle life for the next-generation flexible electronic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A binder-free Bendable RuO<SUB>2</SUB> thin film is fabricated on a graphene/Cu substrate using an electroplating method. </LI> <LI> Electrochemical energy storage properties of RuO<SUB>2</SUB> are investigated for supercapacitor applications. </LI> <LI> Excellent capacitance retention and electrochemical stability are obtained. </LI> </UL> </P>

Polyaniline (PANI) Nanofiber Film의 슈퍼캐패시터 특성 연구

김영삼,손재상,주해리,A. I. Inamdar,정웅,임현식,김형상 한국물리학회 2012 새물리 Vol.62 No.4

In this study, polyaniline (PANI) films were deposited onto ITO substrates by using a pulse galvanostatic method (PGM) for growth times ranging from 900 s to 1800 s. The morphology of the PANI film was characterized using field emission scanning electron microscopy (SEM) and was found to have a nanofiber morphology. The electrochemical properties of the PANI films were measured in a 0.5M LiClO_4 electrolyte by using cyclic voltammetry (CV). When the growth time was 1500 s, the highest specific capacitance of the PANI film was sim713 F/g. Its electrochemical stability was measured in the same electrolyte. When the growth time of the PANI film was 900 s, the capacitance loss was sim15 % after 100 cycles. 본 연구에서는 Pulse galvanostatic method(PGM)을 사용하여 ITO 기판위에 Polyaniline(PANI) nanofiber film을 성장 시간을 900초에서1800초까지 변화시켜 가면서 성장하고 슈퍼캐패시터 특성을 측정하였다. 성장된 PANI film의 표면 특성은 Field Emission Scanning Electron Microscopy(FE-SEM)을 사용하여 측정하였다. SEM image를 통하여 PANI film의 표면이 nanofiber로 성장되었음을 확인하였다. PANI film의전기화학적 특성을 측정하기 위하여 0.5 M LiClO_4에서 Cyclic Voltammetry(CV)를 이용하였다. 성장 시간이 1500초 일 때 캐패시턴스가약 713 F/g으로 가장 높은 값을 가졌다. 전기화학적 안정성을 0.5 M LiClO_4에서 측정하였다. 100 Cycle 후에 900초의 성장 시간을 갖는PANI nanofiber film이 약 15 % capacitance loss를 보였다.