ZnO nanoparticles with different concentrations inside organic solar cell active layer

Saravanan, Shanmugam,Ismail, Yasser A.M.,Silambarasan, Murugesan,Kishi, Naoki,Soga, Tetsuo Techno-Press 2016 Advances in energy research Vol.4 No.4

In the present work, ZnO nanoparticles (NPs) have been dispersed alone in the same solvent of the active layer for improving performance parameters of the organic solar cells. Different concentrations of the ZnO NPs have been blended inside active layer of the solar cell based on poly(3-hexylthiophene) (P3HT), which forms the hole-transport network, and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which forms the electron-transport network. In the present investigations, the ZnO NPs may represent an efficient tool for improving light harvesting through light scattering inside active layer, electron mobility, and electron acceptance strength which tend to improve photocurrent and performance parameters of the investigated solar cell. The fill factor (FF) of the ZnO-doped solar cell increases nearly 14% compared to the non-doped solar cell when the doping is 50%. The present investigations show that ZnO NPs improve power conversion efficiency of the solar cell from 1.23% to 1.64% with increment around 25% that takes place after incorporation of 40% as a volume ratio of the ZnO NPs inside P3HT:PCBM active layer.

POLY(3, 4-ETHYLENEDIOXYTHIOPHENE): POLY(STYRENESULFONATE)/SINGLE-WALL CARBON NANOTUBE COMPOSITE FILM FOR THE HOLE TRANSPORT LAYER IN POLYMER SOLAR CELLS

NAOKI KISHI,SHINYA KATO,TAKESHI SAITO,JUNKI HAYASHI,DAIKI ITO,YASUHIKO HAYASHI,TETSUO SOGA,TAKASHI JIMBO 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2011 NANO Vol.6 No.6

We report the exploration of PEDOT:PSS/SWCNTs as a material for the hole transport layer of polymer solar cells. The electrical conductivity of PEDOT:PSS/SWCNT film was enhanced as compared to that of PEDOT:PSS because of the carrier transport pass through SWCNTs. Moreover, we have fabricated polymer solar cells with the hole transport layer of PEDOT:PSS/SWCNTs and demonstrated the improvement of a fill factor and short circuit current density in the polymer solar cells with the hole transport layer of PEDOT:PSS/SWCNT as compared to the PEDOT:PSS.

Study on the Effect of Nitrogen-Ion Implantation in Semi-Insulating InP by Using Scanning Tunneling Microscopy

Jayavel P,Cheul-Ro LEE,아소칸,Haris M,Hayakawa Y,santhakumar k,Tetsuo soga 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.2I

The effects of low-energy (110 keV) nitrogen ion (N$^+$) implantation at fluences of 1 $\times$ 10$^{13}$ and 1 $\times$ 10$^{14}$ cm$^{-2}$ in semi-insulating InP samples have been studied using cross sectional scanning tunneling microscopy. The atomically resolved images of the implanted samples reveal lattice disordering and point defects, which are attributed to implantation-induced effects. At fluence of 1 $\times$ 10$^{14}$ cm$^{-2}$, deformation of the atomic structures is observed. Cleaved-edge tunneling spectroscopy of the implanted samples has been carried out under dark conditions. The observed results demonstrate that two components of current are associated with the tunneling characteristics. Furthermore, the N$^+$ implantation is observed to induce extended states in the conduction band in which the tunneling of electrons occur. Our results suggest that low-energy N$^+$ implantation influences the atomic structures and the tunneling spectra of low-conductivity InP.

On the Study of the Atomic Structures of Nitrogen-Ion-Implanted InP

santhakumar K,이철로,아소칸,Hayakawa Y,Jayavel p,Tetsuo soga 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.2I

Nitrogen ions at doses of 1 $\times$ 10$^{13}$ -- 1 $\times$ 10$^{15}$ cm$^{-2}$ have been implanted in semi-insulating (SI) InP (100) single-crystal substrates. The surface topography of as-grown and implanted samples has been investigated using atomic force microscopy (AFM). The as-grown InP surface has minimum roughness and appears to be smooth. Angstrom-level pits-type defects are seen on the InP surface after the implantation. Root-mean-square roughness values measured for the as-grown and the implanted InP samples. The surface roughness increased with increasing the nitrogen-ion dose monotonically up to 5 $\times$ 10$^{14}$ cm$^{-2}$ and decreased at a dose of 1 $\times$ 10$^{15}$ cm$^{-2}$ the increase in the roughness was due to implantation-induced damages, and the decrease at higher dose 10$^{15}$ cm$^{-2}$ might have been be due to plastic deformation on the surface associated with a surface amorphisation. Post-implantation annealing smoothened the surface. Roughness values decreased relative to the implanted samples up to a dose 5 $\times$ 10$^{14}$ cm$^{-2}$, which indicates that the defects were partially annealed. At a higher dose of 10$^{15}$ cm$^{-2}$, there was no change in roughness value in spite of annealing. This indicates that the InP surface had been plastically deformed leading to amorphization at higher dose. Further, Raman characterization of these implanted samples clearly supports the surface amorphization at higher doses.

Formation and characterization of MEH-PPV/PCBM-based bulk heterojunction solar cells

Takeo Oku,Syuichi Nagaoka,Atsushi Suzuki,Kenji Kikuchi,Yasuhiko Hayashi,Hayato Sakuragi,Tetsuo Soga 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

Polymer/fullerene bulk heterojunction solar cells with poly[2-methoxy-5-(20-ethylhexoxy)-1,4-phenylenevinylene] (MEH-PPV), zinc-phthalocyanine (ZnPc) and 6,6-phenyl C61-butyric acid methyl ester (PCBM), were produced and characterized. A device based on MEH-PPV and PCBM provided better efficiency, fill factor and short-circuit current compared to those of a device on MEH-PPV(ZnPc) and PCBM. The solar cells with a MEH-PPV and PCBM structure showed a higher photoresponse in the range of 300 to 60 nm. The energy levels of the molecules were calculated and are discussed. Polymer/fullerene bulk heterojunction solar cells with poly[2-methoxy-5-(20-ethylhexoxy)-1,4-phenylenevinylene] (MEH-PPV), zinc-phthalocyanine (ZnPc) and 6,6-phenyl C61-butyric acid methyl ester (PCBM), were produced and characterized. A device based on MEH-PPV and PCBM provided better efficiency, fill factor and short-circuit current compared to those of a device on MEH-PPV(ZnPc) and PCBM. The solar cells with a MEH-PPV and PCBM structure showed a higher photoresponse in the range of 300 to 60 nm. The energy levels of the molecules were calculated and are discussed.

Functionalization of multi-walled carbon nanotubes (MWCNTs) with nitrogen plasma for photovoltaic device application

Golap Kalita,Sudip Adhikari,Hare Ram Aryal,Rakesh Afre,Tetsuo Soga,Maheshwar Sharon,Masayoshi Umeno 한국물리학회 2009 Current Applied Physics Vol.9 No.3

Multi-walled carbon nanotubes (MWCNTs) placed under nitrogen (N2) and argon (Ar) microwave plasma in order to functionalize covalently their side walls with nitrogen containing groups. X-ray photoelectron spectroscopy (XPS) study shows surface modification of the MWCNTs with imine, amine, nitride and amide groups grafted on the side walls. Due to the functional groups, homogenous distribution of MWCNTs in solvent could be obtained. For photovoltaic device fabrication MWCNTs film was casted over n-Si wafer and poly(3-octylthiophene) solution was infiltered. Devices with functionalized MWCNTs show short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF) and power conversion efficiency (g) as 1.8 mA/㎠, 0.20 V, 24% and 0.086%, respectively. In the composite film functionalized MWCNTs facilitate photo induced charge separation and efficient holes transportation, suppressing recombination of photo generated charges. Multi-walled carbon nanotubes (MWCNTs) placed under nitrogen (N2) and argon (Ar) microwave plasma in order to functionalize covalently their side walls with nitrogen containing groups. X-ray photoelectron spectroscopy (XPS) study shows surface modification of the MWCNTs with imine, amine, nitride and amide groups grafted on the side walls. Due to the functional groups, homogenous distribution of MWCNTs in solvent could be obtained. For photovoltaic device fabrication MWCNTs film was casted over n-Si wafer and poly(3-octylthiophene) solution was infiltered. Devices with functionalized MWCNTs show short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF) and power conversion efficiency (g) as 1.8 mA/㎠, 0.20 V, 24% and 0.086%, respectively. In the composite film functionalized MWCNTs facilitate photo induced charge separation and efficient holes transportation, suppressing recombination of photo generated charges.

Study on the Effects of H+ and He+ Implantation in Semi-Insulating GaAs by Using Raman Spectroscopy

santhakumar kannappan,Cheul-Ro LEE,Hayakawa Y,Jayavel P,Jin soo Kim,Kesavamoorthy R,Muraleedaran Nair,Tetsuo soga 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.2I

Fifty-keV hydrogen-ion (H$^+$) and 70-keV helium-ion (He$^+$) implantation with doses from 10$^{13}$ to 10$^{16}$ cm$^{-2}$ in semi-insulating (100) gallium-arsenide (GaAs) single- crystal substrates have been carried out. Raman spectra of as-grown, implanted, and post-implantation-annealed GaAs samples are analyzed. Two LO phonon modes have been observed for all the samples. The lower wavenumber peak is attributed to the strained surface layer whereas the higher wavenumber peak is due to bulk GaAs crystal. For H$^+$ implantation, the peak positions of both peaks shift towards lower wavenumber up to a dose of 10$^{14}$ cm$^{-2}$ due to passivation of charge carriers. For higher doses, the peak positions shift towards higher wavenumber due to hydrogen-filled vacancy loops. On the other hand, for He$^+$-implanted samples, the peak positions increase for doses up to 10$^{13}$ cm$^{-2}$ and then decrease at higher doses. The immiscible nature of helium at low doses causes the increase in the peak positions. In contrast, implantation-induced damage is dominant at higher doses. Implantation-induced defects are partially annealed by post-implantation annealing, causing a blueshift of the peak positions for the H$^+$-implanted samples. In He$^+$-implanted samples, the peak positions redshift due to annealing of He interstitials at low doses and blueshift due to annealing of implantation-induced defects at high doses.