The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Reyad Shawabkeh - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of zinc oxide titanium dioxide zno tio2 nanocomposites by wet incipient wetness impregnation method and preparation of zno tio2 paste using poly vinylpyrrolidone for efficient dye sensitized Solar Cells
    Electrochimica Acta, 2016
    Co-Authors: Waqar Ahmad, Umer Mehmood, Amir Alahmed, Fahad A Alsulaiman, Zaheer M Aslam, Muhammad Shahzad Kamal, Reyad Shawabkeh
    Abstract:

    Abstract The overall objective of this study is to enhance the power conversion efficiency of dye-sensitized Solar Cells (DSSCs) by employing nanocomposite photoanodes. Nanocomposites of TiO 2 with ZnO were synthesized by impregnation method. ZnO nanoparticles were impregnated on TiO 2 in different concentrations and then characterized by Brunauer–Emmett–Teller (BET), X-ray powder diffraction (XRD) and scanning electron microscopy- energy-dispersive X-ray (SEM-EDX) analyses. Thin film photoanodes were prepared using composite paste with poly(vinylpyrrolidone) as a binder. Solar Cells fabricated with ZnO/TiO 2 nanocomposites photoanodes were characterized by photocurrent–voltage characteristic, Incident photon-to-current efficiency, and electrochemical impedance spectroscopy measurements. The results show that the DSSC Based on ZnO/TiO 2 film with an optimum concentration of ZnO (3 wt%) shows power conversion efficiency of 8.10%, improved by 28% compared to that of pure TiO 2 Based Solar Cell. The increase in efficiency can be attributed to fast electron transport, improve light harvesting efficiency, and enhanced electron collection at photoanodes.

Hisao Uchiki - One of the best experts on this subject based on the ideXlab platform.

  • cu2znsns4 thin film Solar Cells prepared by non vacuum processing
    Solar Energy Materials and Solar Cells, 2009
    Co-Authors: Kunihiko Tanaka, Masatoshi Oonuki, Noriko Moritake, Hisao Uchiki
    Abstract:

    Abstract Cu 2 ZnSnS 4 (CZTS)-Based Solar Cell devices were prepared entirely by non-vacuum deposition techniques on soda lime glass (SLG) substrates. The ZnO:Al window, CdS buffer and CZTS absorber layers of the Al/ZnO:Al/CdS/CZTS/Mo/SLG Solar Cell structure were deposited by sol–gel method, chemical bath deposition method and sol–gel sulfurizing method, respectively. The best Solar Cell sample showed an open-circuit voltage of 390 mV, a short-circuit current density of 7.8 mA / cm 2 , a fill factor of 0.33 and an efficiency of 1.01% under irradiation of AM 1.5 and 100 mW / cm 2 . This is the first report on CZTS thin film Solar Cells in which all the semiconductor layers were prepared under non-vacuum condition.

Mohammad Khaja Nazeeruddin - One of the best experts on this subject based on the ideXlab platform.

  • light harvesting and charge recombination in ch3nh3pbi3 perovskite Solar Cells studied by hole transport layer thickness variation
    ACS Nano, 2015
    Co-Authors: Nevena Marinova, Mohammad Khaja Nazeeruddin, Shaik M Zakeeruddin, Wolfgang Tress, Robin Humphrybaker, Ibrahim M Dar, Vladimir B Bojinov, Michael Gratzel
    Abstract:

    A tailored optimization of perovskite Solar Cells requires a detailed understanding of the processes limiting the device efficiency. Here, we study the role of the hole transport layer (HTL) spiro-MeOTAD and its thickness in a mesoscopic TiO2-Based Solar Cell architecture. We find that a sufficiently thick (200 nm) HTL not only increases the charge carrier collection efficiency but also the light harvesting efficiency. This is due to an enhanced reflection of a smooth HTL/Au–electrode interface. The rough CH3NH3PbI3 perovskite surface requires an HTL thickness of >400 nm to avoid surface recombination and guarantee a high open-circuit voltage. Analyses of the electroluminescence efficiency and the diode ideality factor show that the open-circuit voltage becomes completely limited by trap-assisted recombination in the perovskite for a thick HTL. Thus, spiro-MeOTAD is a very good HTL choice from the device physics’ point of view. The fill factor analyzed by the Suns-Voc method is not transport limited, but ...

  • efficient star shaped hole transporting materials with diphenylethenyl side arms for an efficient perovskite Solar Cell
    Journal of Materials Chemistry, 2014
    Co-Authors: Hyeju Choi, Sojin Park, Sanghyun Paek, Piyasiri Ekanayake, Mohammad Khaja Nazeeruddin
    Abstract:

    Two symmetrical star-shaped hole transporting materials (HTMs), i.e.FA-MeOPh and TPA-MeOPh with a fused triphenylamine or triphenylamine core and diphenylethenyl side arms were synthesized. FA-MeOPh showed a strong molar absorption coefficient and a red-shifted absorption compared with TPA-MeOPh because of its planar configuration. The power conversion efficiency (PCE) of the perovskite Solar Cells Based on FA-MeOPh and TPA-MeOPh is about 11.86% and 10.79%, in which the efficiency of former is comparable to that (12.75%) of spiro-OMeTAD Based Cell. The high photocurrent (18.39 mA cm−2) of FA-MeOPh Based Solar Cell relative to TPA-MeOPh Based one may be attributable to the enhanced absorption in the near-IR region for mp-TiO2/CH3NH3PbI3/HTM Based Cell. The high mobility and low series resistance of mp-TiO2/CH3NH3PbI3/FA-MeOPh Based Cell led to the high fill factor (0.698) of FA-MeOPh Based Solar Cell relative to TPA-MeOPh Based one (0.627). In addition, the FA-MeOPh Based Cell showed a relative stability under light soaking for 250 h. The high efficiency, relative stability, synthetically simple and inexpensive materials as the HTMs hold promise to replace the expensive spiro-OMeTAD.

  • star shaped hole transporting materials with a triazine unit for efficient perovskite Solar Cells
    Chemical Communications, 2014
    Co-Authors: Hyeju Choi, Kimin Lim, Jin Woo Cho, Mohammad Khaja Nazeeruddin
    Abstract:

    Novel star-shaped hole transporting materials with a triazine unit have been synthesized. When the new Triazine-Th-OMeTPA was used as a hole transporting material in perovskite Solar Cells, the power conversion efficiency reached 12.51% under AM 1.5 G (100 mW cm(-2)) illumination, showing competitive photovoltaic performance with the widely used spiro-OMeTAD Based Solar Cell (13.45%).

  • using a two step deposition technique to prepare perovskite ch3nh3pbi3 for thin film Solar Cells Based on zro2 and tio2 mesostructures
    RSC Advances, 2013
    Co-Authors: Dongqin Bi, Michael Gratzel, Soojin Moon, Leif Haggman, Gerrit Boschloo, Lei Yang, Erik M J Johansson, Mohammad Khaja Nazeeruddin, Anders Hagfeldt
    Abstract:

    A two-step deposition technique is used for preparing CH3NH3PbI3 perovskite Solar Cells. Using ZrO2 and TiO2 as a mesoporous layer, we obtain an efficiency of 10.8% and 9.5%, respectively, under 1000 W m−2 illumination. The ZrO2 Based Solar Cell shows higher photovoltage and longer electron lifetime than the TiO2 Based Solar Cell.

Michael Gratzel - One of the best experts on this subject based on the ideXlab platform.

  • light harvesting and charge recombination in ch3nh3pbi3 perovskite Solar Cells studied by hole transport layer thickness variation
    ACS Nano, 2015
    Co-Authors: Nevena Marinova, Mohammad Khaja Nazeeruddin, Shaik M Zakeeruddin, Wolfgang Tress, Robin Humphrybaker, Ibrahim M Dar, Vladimir B Bojinov, Michael Gratzel
    Abstract:

    A tailored optimization of perovskite Solar Cells requires a detailed understanding of the processes limiting the device efficiency. Here, we study the role of the hole transport layer (HTL) spiro-MeOTAD and its thickness in a mesoscopic TiO2-Based Solar Cell architecture. We find that a sufficiently thick (200 nm) HTL not only increases the charge carrier collection efficiency but also the light harvesting efficiency. This is due to an enhanced reflection of a smooth HTL/Au–electrode interface. The rough CH3NH3PbI3 perovskite surface requires an HTL thickness of >400 nm to avoid surface recombination and guarantee a high open-circuit voltage. Analyses of the electroluminescence efficiency and the diode ideality factor show that the open-circuit voltage becomes completely limited by trap-assisted recombination in the perovskite for a thick HTL. Thus, spiro-MeOTAD is a very good HTL choice from the device physics’ point of view. The fill factor analyzed by the Suns-Voc method is not transport limited, but ...

  • hole transporting small molecules Based on thiophene cores for high efficiency perovskite Solar Cells
    Chemsuschem, 2014
    Co-Authors: Pablo P Boix, Anders Hagfeldt, Michael Gratzel, S G Mhaisalkar, Lydia Helena Wong, Andrew C Grimsdale
    Abstract:

    Two new electron-rich molecules, 2,3,4,5-tetra[4,4'-bis(methoxyphenyl)aminophen-4 ''-yl]-thiophene (H111) and 4,4',5,5'-tetra[4,4'-bis(methoxyphenyl) aminophen-4 ''-yl]-2,2'-bithiophene (H112), which contain thiophene cores with arylamine side groups, are reported. When used as the hole-transporting material (HTM) in perovskite-Based Solar Cell devices, power conversion efficiencies of up to 15.4% under AM 1.5G Solar simulation were obtained. This is the highest efficiency achieved with HTMs not composed of 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) and its isomers. Both HTMs, especially H111, have great potential to replace expensive spiro-OMeTAD given their much simpler and less expensive syntheses.

  • a simple 3 4 ethylenedioxythiophene Based hole transporting material for perovskite Solar Cells
    Angewandte Chemie, 2014
    Co-Authors: Hairong Li, Kunwu Fu, Anders Hagfeldt, Michael Gratzel, S G Mhaisalkar, Andrew C Grimsdale
    Abstract:

    We report a novel electron-rich molecule Based on 3,4-ethylenedioxythiophene (H101). When used as the hole-transporting layer in a perovskite-Based Solar Cell, the power-conversion efficiency reached 13.8% under AM 1.5G Solar simulation. This result is comparable with that obtained using the well-known hole transporting material 2,2,7,7-tetrakis(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (spiro-OMeTAD). This is the first heterocycle-containing material achieving >10% efficiency in such devices, and has great potential to replace the expensive spiro-OMeTAD given its much simpler and cheaper synthesis.

  • using a two step deposition technique to prepare perovskite ch3nh3pbi3 for thin film Solar Cells Based on zro2 and tio2 mesostructures
    RSC Advances, 2013
    Co-Authors: Dongqin Bi, Michael Gratzel, Soojin Moon, Leif Haggman, Gerrit Boschloo, Lei Yang, Erik M J Johansson, Mohammad Khaja Nazeeruddin, Anders Hagfeldt
    Abstract:

    A two-step deposition technique is used for preparing CH3NH3PbI3 perovskite Solar Cells. Using ZrO2 and TiO2 as a mesoporous layer, we obtain an efficiency of 10.8% and 9.5%, respectively, under 1000 W m−2 illumination. The ZrO2 Based Solar Cell shows higher photovoltage and longer electron lifetime than the TiO2 Based Solar Cell.

  • high molar extinction coefficient organic sensitizers for efficient dye sensitized Solar Cells
    Chemistry: A European Journal, 2010
    Co-Authors: Hyunbong Choi, Kihyung Song, Junho Yum, Md K Nazeeruddin, Ines Raabe, Duckhyun Kim, Francesca Teocoli, Chulwoo Kim, Michael Gratzel
    Abstract:

    We have designed and synthesized highly efficient organic sensitizers with a planar thienothiophene-vinylene-thienothiophene linker. Under standard global AM 1.5 Solar conditions, the JK-113-sensitized Cell gave a short circuit photocurrent density (J(sc)) of 17.61 mAcm(-2), an open-circuit voltage (V-oc) of 0.71 V, and a fill factor (FF) of 72%, corresponding to an overall conversion efficiency (eta) of 9.1%. The incident monochromatic photo-to-current conversion efficiency (IPCE) of JK-113 exceeds 80% over the spectral region from 400 to 640 nm, reaching its maximum of 93% at 475 nm. The band tails off toward 770 nm, contributing to the broad spectral light harvesting. Solar-Cell devices Based oil the sensitizer JK-113 in conjunction with a volatile electrolyte and a solvent-free ionic liquid electrolyte gave high conversion efficiencies of 9.1% and 7.9%, respectively. The JK-113-Based Solar Cell fabricated using a solvent-free ionic liquid electrolyte showed exCellent stability under light soaking at 60 degrees C for 1000 h.

R Klenk - One of the best experts on this subject based on the ideXlab platform.

  • 12 6 efficient cds cu in ga s2 Based Solar Cell with an open circuit voltage of 879 mv prepared by a rapid thermal process
    Solar Energy Materials and Solar Cells, 2011
    Co-Authors: S Merdes, R Mainz, J Klaer, A Meeder, H Rodriguezalvarez, H W Schock, Ch M Luxsteiner, R Klenk
    Abstract:

    Abstract A Cu(In,Ga)S 2 -Based Solar Cell with a confirmed efficiency of 12.6% together with an open circuit voltage of 879 mV, prepared from sputtered metals subsequently sulfurized using rapid thermal processing in sulfur vapor, is reported. The performance of the new Cell is superior to those obtained previously with multi-source evaporated absorbers. We show that by carefully adjusting the temperature profile, good absorber properties could be transferred from a long process to a rapid thermal process. The improved efficiency is due to an appropriate degree of gallium diffusion toward the surface, which could be achieved despite the short sulfurization time. Absorber and Solar Cell characteristics are presented.

  • efficient cuins2 Solar Cells from a rapid thermal process rtp
    Solar Energy Materials and Solar Cells, 2001
    Co-Authors: K Siemer, R Klenk, Jo Klaer, Ilka Luck, Jurgen Bruns, D Braunig
    Abstract:

    Abstract CuInS2-Based Solar Cells are prepared by a rapid thermal process (RTP). We use a sequential preparation with metallic layers of Cu and In rapidly heated in elemental sulfur vapor. Absorber layers from this process show good crystallinity, as seen from XRD and SEM. For further analysis of the defect chemistry, photoluminescence and admittance spectroscopy measurements are carried out. Solar Cells prepared from these RTP absorbers have reached 11.4% total area efficiency (A=0.5 cm2), which is to our knowledge the best CuInS2-Based Solar Cell so far.