High-efficiency polymer solar cells with small photon energy loss

A crucial issue facing polymer-based solar cells is how to manage the energetics of the polymer/fullerene blends to maximize short-circuit current density and open-circuit voltage at the same time and thus the power conversion efficiency. Here we demonstrate that the use of a naphthobisoxadiazole-based polymer with a narrow bandgap of 1.52 eV leads to high open-circuit voltages of approximately 1 V and high-power conversion efficiencies of ∼9% in solar cells, resulting in photon energy loss as small as ∼0.5 eV, which is much smaller than that of typical polymer systems (0.7–1.0 eV). This is ascribed to the high external quantum efficiency for the systems with a very small energy offset for charge separation. These unconventional features of the present polymer system will inspire the field of polymer-based solar cells towards further improvement of power conversion efficiencies with both high short-circuit current density and open-circuit voltage.

[1]  J. Fréchet,et al.  Polymer-fullerene composite solar cells. , 2008, Angewandte Chemie.

[2]  P. Chou,et al.  A silole copolymer containing a ladder-type heptacylic arene and naphthobisoxadiazole moieties for highly efficient polymer solar cells , 2015 .

[3]  T. Russell,et al.  A low band-gap polymer based on unsubstituted benzo[1,2-b:4,5-b']dithiophene for high performance organic photovoltaics. , 2012, Chemical communications.

[4]  R. Flinn.  The challenges. , 1979, Delaware medical journal.

[5]  Mario Leclerc,et al.  Processable Low-Bandgap Polymers for Photovoltaic Applications† , 2011 .

[6]  Guillermo C Bazan,et al.  "Plastic" solar cells: self-assembly of bulk heterojunction nanomaterials by spontaneous phase separation. , 2009, Accounts of chemical research.

[7]  H. Ohkita,et al.  Charge generation and recombination dynamics in poly(3-hexylthiophene)/fullerene blend films with different regioregularities and morphologies. , 2010, Journal of the American Chemical Society.

[8]  O. Inganäs,et al.  Charge-Transfer States and Upper Limit of the Open-Circuit Voltage in Polymer:Fullerene Organic Solar Cells , 2010, IEEE Journal of Selected Topics in Quantum Electronics.

[9]  Mats Andersson,et al.  Quantification of Quantum Efficiency and Energy Losses in Low Bandgap Polymer:Fullerene Solar Cells with High Open‐Circuit Voltage , 2012 .

[10]  T. Russell,et al.  A high mobility conjugated polymer based on dithienothiophene and diketopyrrolopyrrole for organic photovoltaics , 2012 .

[11]  He Yan,et al.  Aggregation and morphology control enables multiple cases of high-efficiency polymer solar cells , 2014, Nature Communications.

[12]  Pierre M Beaujuge,et al.  Synthetic control of structural order in N-alkylthieno[3,4-c]pyrrole-4,6-dione-based polymers for efficient solar cells. , 2010, Journal of the American Chemical Society.

[13]  Daisuke Mori,et al.  Highly efficient charge-carrier generation and collection in polymer/polymer blend solar cells with a power conversion efficiency of 5.7% , 2014 .

[14]  Christoph J. Brabec,et al.  Organic Photovoltaics: Materials, Device Physics, and Manufacturing Technologies , 2014 .

[15]  Weiwei Li,et al.  High quantum efficiencies in polymer solar cells at energy losses below 0.6 eV. , 2015, Journal of the American Chemical Society.

[16]  S. Mannsfeld,et al.  Quantitative determination of organic semiconductor microstructure from the molecular to device scale. , 2012, Chemical reviews.

[17]  Kazuhito Hashimoto,et al.  Bilayer ambipolar organic thin-film transistors and inverters prepared by the contact-film-transfer method. , 2009, ACS applied materials & interfaces.

[18]  T. Koganezawa,et al.  Naphthodithiophene-naphthobisthiadiazole copolymers for solar cells: alkylation drives the polymer backbone flat and promotes efficiency. , 2013, Journal of the American Chemical Society.

[19]  Antonio Facchetti,et al.  π-Conjugated Polymers for Organic Electronics and Photovoltaic Cell Applications† , 2011 .

[20]  S. Jenekhe,et al.  n-Type semiconducting naphthalene diimide-perylene diimide copolymers: controlling crystallinity, blend morphology, and compatibility toward high-performance all-polymer solar cells. , 2015, Journal of the American Chemical Society.

[21]  I. Osaka,et al.  Effect of Chalcogen Atom on the Properties of Naphthobischalcogenadiazole-Based π-Conjugated Polymers , 2015 .

[22]  Seth Pettie,et al.  Mind the gap , 2006, Nature Reviews Drug Discovery.

[23]  George F. A. Dibb,et al.  Understanding the Reduced Efficiencies of Organic Solar Cells Employing Fullerene Multiadducts as Acceptors , 2013 .

[24]  Raj René Janssen,et al.  The Energy of Charge‐Transfer States in Electron Donor–Acceptor Blends: Insight into the Energy Losses in Organic Solar Cells , 2009 .

[25]  Miao Xu,et al.  Enhanced power-conversion efficiency in polymer solar cells using an inverted device structure , 2012, Nature Photonics.

[26]  M. Green,et al.  The emergence of perovskite solar cells , 2014, Nature Photonics.

[27]  Olle Inganäs,et al.  On the origin of the open-circuit voltage of polymer-fullerene solar cells. , 2009, Nature materials.

[28]  Guillermo C Bazan,et al.  Bulk heterojunction solar cells: morphology and performance relationships. , 2014, Chemical reviews.

[29]  Jean Manca,et al.  Relating the open-circuit voltage to interface molecular properties of donor:acceptor bulk heterojunction solar cells , 2010 .

[30]  H. Ohkita,et al.  Transient absorption spectroscopy of polymer-based thin-film solar cells , 2011 .

[31]  H. Ohkita,et al.  Charge-Carrier Generation in Organic Solar Cells with Crystalline Donor Polymers , 2014 .

[32]  H. Queisser,et al.  Detailed Balance Limit of Efficiency of p‐n Junction Solar Cells , 1961 .

[33]  Luping Yu,et al.  Photovoltaic Function and Exciton/Charge Transfer Dynamics in a Highly Efficient Semiconducting Copolymer , 2014 .

[34]  N. S. Sariciftci,et al.  Conjugated polymer-based organic solar cells. , 2007, Chemical reviews.

[35]  D. C. Law,et al.  Band gap‐voltage offset and energy production in next‐generation multijunction solar cells , 2011 .

[36]  Jean-Luc Brédas.  Molecular understanding of organic solar cells: The challenges , 2013 .

[37]  I. Osaka,et al.  Backbone orientation in semiconducting polymers , 2015 .

[38]  Weimin Zhang,et al.  Charge carrier formation in polythiophene/fullerene blend films studied by transient absorption spectroscopy. , 2008, Journal of the American Chemical Society.

[39]  Christoph J. Brabec,et al.  Design Rules for Donors in Bulk‐Heterojunction Solar Cells—Towards 10 % Energy‐Conversion Efficiency , 2006 .

[40]  Gang Li,et al.  For the Bright Future—Bulk Heterojunction Polymer Solar Cells with Power Conversion Efficiency of 7.4% , 2010, Advanced materials.

[41]  Ergang Wang,et al.  Enhance performance of organic solar cells based on an isoindigo-based copolymer by balancing absorption and miscibility of electron acceptor , 2011 .

[42]  O. Inganäs,et al.  An easily accessible isoindigo-based polymer for high-performance polymer solar cells. , 2011, Journal of the American Chemical Society.

[43]  Shunsuke Yamamoto,et al.  Role of Interfacial Charge Transfer State in Charge Generation and Recombination in Low-Bandgap Polymer Solar Cell , 2012 .

[44]  Kazuhito Hashimoto,et al.  Tailoring organic heterojunction interfaces in bilayer polymer photovoltaic devices. , 2011, Nature materials.

[45]  Robert P. H. Chang,et al.  Polymer solar cells with enhanced fill factors , 2013, Nature Photonics.

[46]  Yu-Shan Cheng,et al.  Single Junction Inverted Polymer Solar Cell Reaching Power Conversion Efficiency 10.31% by Employing Dual-Doped Zinc Oxide Nano-Film as Cathode Interlayer , 2014, Scientific Reports.

[47]  Itaru Osaka,et al.  Efficient inverted polymer solar cells employing favourable molecular orientation , 2015, Nature Photonics.

[48]  Alan J. Heeger,et al.  Recombination in polymer-fullerene bulk heterojunction solar cells , 2010 .

[49]  T. Koganezawa,et al.  Synthesis, characterization, and transistor and solar cell applications of a naphthobisthiadiazole-based semiconducting polymer. , 2012, Journal of the American Chemical Society.

[50]  Nelson E. Coates,et al.  Bulk heterojunction solar cells with internal quantum efficiency approaching 100 , 2009 .

[51]  Antonio Facchetti,et al.  Polymer donor–polymer acceptor (all-polymer) solar cells , 2013 .

[52]  Bryon W. Larson,et al.  Electron Affinity of Phenyl–C61–Butyric Acid Methyl Ester (PCBM) , 2013 .

[53]  H. Ohkita,et al.  Light-Harvesting Mechanism in Polymer/Fullerene/Dye Ternary Blends Studied by Transient Absorption Spectroscopy , 2011 .

[54]  Thuc‐Quyen Nguyen,et al.  High open circuit voltage in regioregular narrow band gap polymer solar cells. , 2014, Journal of the American Chemical Society.