Light energy conversion by mesoscopic PbS quantum dots/TiO2 heterojunction solar cells.

Solid state PbS quantum dots (QDs)/TiO(2) heterojunction solar cells were produced by depositing PbS QDs on a 500 nm thick mesoscopic TiO(2) films using layer-by-layer deposition. Importantly, the PbS QDs act here as photosensitizers and at the same time as hole conductors. The PbS QDs/TiO(2) device produces a short circuit photocurrent (J(sc)) of 13.04 mA/cm(2), an open circuit photovoltage (V(oc)) of 0.55 V and a fill factor (FF) of 0.49, corresponding to a light to electric power conversion efficiency (η) of 3.5% under AM1.5 illumination. The electronic processes occurring in this device were investigated by transient photocurrent and photovoltage measurements as well as impedance spectroscopy in the dark and under illumination. The investigations showed a high resistivity for the QD/metal back contact, which reduces drastically under illumination. EIS also indicated a shift of the depletion layer capacitance under illumination related to the change of the dipole at this interface.

[1]  Matt Law,et al.  Dependence of carrier mobility on nanocrystal size and ligand length in PbSe nanocrystal solids. , 2010, Nano letters.

[2]  F. Wise,et al.  Lead salt quantum dots: the limit of strong quantum confinement. , 2000, Accounts of chemical research.

[3]  Edward H. Sargent,et al.  Schottky-quantum dot photovoltaics for efficient infrared power conversion , 2008 .

[4]  G. Konstantatos,et al.  Enhanced infrared photovoltaic efficiency in PbS nanocrystal/semiconducting polymer composites: 600-fold increase in maximum power output via control of the ligand barrier , 2005 .

[5]  Victor I Klimov,et al.  Hybrid photovoltaics based on semiconductor nanocrystals and amorphous silicon. , 2009, Nano letters.

[6]  Michael Grätzel,et al.  Morphology and Adsorbate Dependence of Ionic Transport in Dye Sensitized Mesoporous TiO2 Films , 1998 .

[7]  S. Haque,et al.  PbS and CdS Quantum Dot‐Sensitized Solid‐State Solar Cells: “Old Concepts, New Results” , 2009 .

[8]  R. Schaller,et al.  High efficiency carrier multiplication in PbSe nanocrystals: implications for solar energy conversion. , 2004, Physical review letters.

[9]  Lukasz Brzozowski,et al.  Ambient-processed colloidal quantum dot solar cells via individual pre-encapsulation of nanoparticles. , 2010, Journal of the American Chemical Society.

[10]  Edward H. Sargent,et al.  Efficient, stable infrared photovoltaics based on solution-cast colloidal quantum dots. , 2008, ACS nano.

[11]  A Paul Alivisatos,et al.  Air-Stable All-Inorganic Nanocrystal Solar Cells Processed from Solution , 2005, Science.

[12]  B. Liedberg,et al.  Chemisorption of -cysteine and 3-mercaptopropionic acid on gold and copper surfaces: An infrared reflection-absorption study , 1991 .

[13]  Matt Law,et al.  Schottky solar cells based on colloidal nanocrystal films. , 2008, Nano letters.

[14]  Frank Lenzmann,et al.  Charge Transport and Recombination in a Nanoscale Interpenetrating Network of n-Type and p-Type Semiconductors: Transient Photocurrent and Photovoltage Studies of TiO2/Dye/CuSCN Photovoltaic Cells , 2004 .

[15]  Jennifer A Hollingsworth,et al.  Pushing the band gap envelope: mid-infrared emitting colloidal PbSe quantum dots. , 2004, Journal of the American Chemical Society.

[16]  Edward H. Sargent,et al.  Depleted-heterojunction colloidal quantum dot photovoltaics employing low-cost electrical contacts , 2010 .

[17]  A. Alivisatos,et al.  Hybrid Nanorod-Polymer Solar Cells , 2002, Science.

[18]  Michael Grätzel,et al.  Charge collection and pore filling in solid-state dye-sensitized solar cells , 2008, Nanotechnology.

[19]  Gregory D. Scholes,et al.  Colloidal PbS Nanocrystals with Size‐Tunable Near‐Infrared Emission: Observation of Post‐Synthesis Self‐Narrowing of the Particle Size Distribution , 2003 .

[20]  Peng Wang,et al.  An organic D-π-A dye for record efficiency solid-state sensitized heterojunction solar cells. , 2011, Nano letters.

[21]  Juan Bisquert,et al.  Charge carrier mobility and lifetime of organic bulk heterojunctions analyzed by impedance spectroscopy , 2008 .

[22]  Sung Jin Kim,et al.  Enhancement of the photovoltaic performance in PbS nanocrystal:P3HT hybrid composite devices by post-treatment-driven ligand exchange , 2009, Nanotechnology.

[23]  J. Schoonman,et al.  CuInS2 TiO2 heterojunctions solar cells obtained by atomic layer deposition , 2003 .

[24]  Jian Xu,et al.  Harvest of near infrared light in PbSe nanocrystal-polymer hybrid photovoltaic cells , 2006 .

[25]  Matthew C. Beard,et al.  Determining the internal quantum efficiency of PbSe nanocrystal solar cells with the aid of an optical model. , 2008, Nano letters.

[26]  F. Fabregat‐Santiago,et al.  From flat to nanostructured photovoltaics: balance between thickness of the absorber and charge screening in sensitized solar cells. , 2012, ACS nano.

[27]  J. Sites,et al.  Hole current impedance and electron current enhancement by back-contact barriers in CdTe thin film solar cells , 2006 .

[28]  S. Carter,et al.  All-inorganic CdSe/PbSe nanoparticle solar cells , 2008 .

[29]  M. Turner,et al.  Nanoparticle-polymer photovoltaic cells. , 2008, Advances in colloid and interface science.

[30]  Udo Bach,et al.  Quantum dot sensitization of organic-inorganic hybrid solar cells , 2002 .

[31]  J. Bisquert,et al.  Band unpinning and photovoltaic model for P3HT:PCBM organic bulk heterojunctions under illumination , 2008 .

[32]  Ratan Debnath,et al.  Depleted-heterojunction colloidal quantum dot solar cells. , 2010, ACS nano.

[33]  Aram Amassian,et al.  Colloidal-quantum-dot photovoltaics using atomic-ligand passivation. , 2011, Nature materials.

[34]  Wje Waldo Beek,et al.  Hybrid Solar Cells from Regioregular Polythiophene and ZnO Nanoparticles , 2006 .

[35]  Byung-Ryool Hyun,et al.  Electron injection from colloidal PbS quantum dots into titanium dioxide nanoparticles. , 2008, ACS nano.

[36]  Matt Law,et al.  Structural, optical, and electrical properties of self-assembled films of PbSe nanocrystals treated with 1,2-ethanedithiol. , 2008, ACS nano.

[37]  A. Maldonado,et al.  Physical properties of ZnO:F obtained from a fresh and aged solution of zinc acetate and zinc acetylacetonate , 2006 .

[38]  Prashant V. Kamat,et al.  Quantum Dot Solar Cells. Semiconductor Nanocrystals as Light Harvesters , 2008 .

[39]  Jianbo Gao,et al.  Quantum dot size dependent J-V characteristics in heterojunction ZnO/PbS quantum dot solar cells. , 2011, Nano letters.

[40]  C. Grimes,et al.  Self-Organized One-Dimensional TiO Nanotube/Nanowire Array Films for Use in Excitonic Solar Cells: A Review , 2012 .

[41]  Jianbo Gao,et al.  Stability Assessment on a 3% Bilayer PbS/ZnO Quantum Dot Heterojunction Solar Cell , 2010, Advanced materials.

[42]  T. Krauss,et al.  Ultrabright PbSe magic-sized clusters. , 2008, Nano letters.

[43]  C. Voz,et al.  Effect of buffer layer on minority carrier lifetime and series resistance of bifacial heterojunction silicon solar cells analyzed by impedance spectroscopy , 2006 .

[44]  A Paul Alivisatos,et al.  Photovoltaic devices employing ternary PbSxSe1-x nanocrystals. , 2009, Nano letters.

[45]  H. Hillhouse,et al.  Solar cells from colloidal nanocrystals: Fundamentals, materials, devices, and economics , 2009 .

[46]  M. Kovalenko,et al.  Quasi-seeded growth of ligand-tailored PbSe nanocrystals through cation-exchange-mediated nucleation. , 2008, Angewandte Chemie.