The influence of additives on the morphology and stability of roll-to-roll processed polymer solar cells studied through ex situ and in situ X-ray scattering

The effect of twelve different additives on organic solar cells with an active layer based on poly-3-hexylthiophene (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) has been studied in this work and tested for suitability in roll-to-roll slot-die coating. Three of the twelve additives increased the solar cell efficiency while the rest showed no effect or a negative influence on the efficiency and coatability. In cases where the additive caused an increase in performance the relation to surface topography and the structure was investigated using Atomic Force Microscopy (AFM), UV-Vis Spectroscopy and Small Angle X-ray Scattering (SAXS) for cells prepared with 1-chloronaphthalene (CN), N-methyl-2-pyrrolidone (NMP) and 1,3-dimethyl-barbituric acid (BARB) as processing additives. The studies suggested that the use of these additives resulted in films with improved morphology and electrical properties of the active layer. The effect of the CN on structural evolution during different solvent evaporation and annealing times was further investigated with an in situ roll-to-roll X-ray study. Lifetime studies under continuous illumination were used to assess the impact of the additives on the stability of the prepared devices that had an active area of 1 cm2.

[1]  Gang Li,et al.  Fast-Grown Interpenetrating Network in Poly(3-hexylthiophene): Methanofullerenes Solar Cells Processed with Additive , 2009 .

[2]  G. Wantz,et al.  Controlling the morphology and performance of bulk heterojunctions in solar cells. Lessons learned from the benchmark poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester system. , 2013, Chemical reviews.

[3]  Wasiu Adebayo Hammed,et al.  Recent Approaches to Controlling the Nanoscale Morphology of Polymer-Based Bulk-Heterojunction Solar Cells , 2013 .

[4]  Martin Brinkmann,et al.  Orientation of Regioregular Poly(3‐hexylthiophene) by Directional Solidification: A Simple Method to Reveal the Semicrystalline Structure of a Conjugated Polymer , 2006 .

[5]  Valentin D. Mihailetchi,et al.  Origin of the enhanced performance in poly"3-hexylthiophene…: †6,6‡-phenyl C 61 -butyric acid methyl ester solar cells upon slow drying of the active layer , 2006 .

[6]  Kerry B. Burke,et al.  Vertical Stratification and Interfacial Structure in P3HT:PCBM Organic Solar Cells , 2010 .

[7]  O. Bunk,et al.  Simulating X-ray diffraction of textured films , 2008 .

[8]  Valentin D. Mihailetchi,et al.  Charge Transport and Photocurrent Generation in Poly(3‐hexylthiophene): Methanofullerene Bulk‐Heterojunction Solar Cells , 2006 .

[9]  H. Sirringhaus,et al.  Effect of interchain interactions on the absorption and emission of poly(3-hexylthiophene) , 2003 .

[10]  R. Friend,et al.  Polarization of singlet and triplet excited states in a platinum-containing conjugated polymer , 2003 .

[11]  Jan Fyenbo,et al.  Product integration of compact roll-to-roll processed polymer solar cell modules: methods and manufacture using flexographic printing, slot-die coating and rotary screen printing , 2010 .

[12]  N. S. Sariciftci,et al.  Influence of processing additives to nano-morphology and efficiency of bulk-heterojunction solar cells: A comparative review , 2011 .

[13]  Niyazi Serdar Sariciftci,et al.  Effects of Postproduction Treatment on Plastic Solar Cells , 2003 .

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

[15]  Mikkel Jørgensen,et al.  High-throughput roll-to-roll X-ray characterization of polymer solar cell active layers , 2012 .

[16]  Gang Li,et al.  Investigation of annealing effects and film thickness dependence of polymer solar cells based on poly(3-hexylthiophene) , 2005 .

[17]  E. W. Meijer,et al.  Two-dimensional charge transport in self-organized, high-mobility conjugated polymers , 1999, Nature.

[18]  Yang Yang,et al.  Solution-processed small-molecule solar cells: breaking the 10% power conversion efficiency , 2013, Scientific Reports.

[19]  Feng Liu,et al.  On the morphology of polymer‐based photovoltaics , 2012 .

[20]  Jin Young Kim,et al.  Processing additives for improved efficiency from bulk heterojunction solar cells. , 2008, Journal of the American Chemical Society.

[21]  Yun Zhao,et al.  Solvent-vapor treatment induced performance enhancement of poly(3-hexylthiophene):methanofullerene bulk-heterojunction photovoltaic cells , 2007 .

[22]  S. Forrest,et al.  Exciton diffusion lengths of organic semiconductor thin films measured by spectrally resolved photoluminescence quenching , 2009 .

[23]  Niyazi Serdar Sariciftci,et al.  Morphology of polymer/fullerene bulk heterojunction solar cells , 2006 .

[24]  Markus Hösel,et al.  Roll-to-roll fabrication of polymer solar cells , 2012 .

[25]  E. Gomez,et al.  Altering the Thermodynamics of Phase Separation in Inverted Bulk‐Heterojunction Organic Solar Cells , 2009 .

[26]  L. Wong,et al.  A new insight into controlling poly(3-hexylthiophene) nanofiber growth through a mixed-solvent approach for organic photovoltaics applications , 2011 .

[27]  Zhenan Bao,et al.  Solvent additives and their effects on blend morphologies of bulk heterojunctions , 2011 .

[28]  C. Chu,et al.  A dual-functional additive improves the performance of molecular bulk heterojunction photovoltaic cells , 2014 .

[29]  Mikkel Jørgensen,et al.  Upscaling of polymer solar cell fabrication using full roll-to-roll processing. , 2010, Nanoscale.

[30]  P. Heremans,et al.  Polythiophene based bulk heterojunction solar cells: morphology and its implications , 2006 .

[31]  J. Park,et al.  Enhanced Performance in Polymer Solar Cells by Surface Energy Control , 2010 .

[32]  U. Lemmer,et al.  Effect of Photovoltaic Polymer/Fullerene Blend Composition Ratio on Microstructure Evolution during Film Solidification Investigated in Real Time by X-ray Diffraction , 2011 .

[33]  Mikkel Jørgensen,et al.  A laboratory scale approach to polymer solar cells using one coating/printing machine, flexible substrates, no ITO, no vacuum and no spincoating , 2013 .

[34]  Xiong Gong,et al.  Thermally Stable, Efficient Polymer Solar Cells with Nanoscale Control of the Interpenetrating Network Morphology , 2005 .

[35]  Gang Li,et al.  Control of the nanoscale crystallinity and phase separation in polymer solar cells , 2008 .

[36]  Jong-Hyun Ahn,et al.  Supramolecular barrels from amphiphilic rigid–flexible macrocycles , 2005, Nature materials.

[37]  Suren A. Gevorgyan,et al.  Stability of Polymer Solar Cells , 2012, Advanced materials.

[38]  Kristian O. Sylvester-Hvid,et al.  Ellipsometry as a Nondestructive Depth Profiling Tool for Roll-to-Roll Manufactured Flexible Solar Cells , 2011 .

[39]  Feng Liu,et al.  Characterization of the morphology of solution-processed bulk heterojunction organic photovoltaics , 2013 .

[40]  M. Hampton,et al.  Dynamics of Crystallization and Disorder during Annealing of P3HT/PCBM Bulk Heterojunctions , 2011 .

[41]  Mikkel Jørgensen,et al.  Fast Inline Roll‐to‐Roll Printing for Indium‐Tin‐Oxide‐Free Polymer Solar Cells Using Automatic Registration , 2013 .

[42]  M. Urien,et al.  Polymeric solar cells based on P3HT:PCBM: Role of the casting solvent , 2011 .

[43]  J. Park,et al.  Control of the electrode work function and active layer morphology via surface modification of indium tin oxide for high efficiency organic photovoltaics , 2007 .

[44]  Christoph J. Brabec,et al.  Correlation Between Structural and Optical Properties of Composite Polymer/Fullerene Films for Organic Solar Cells , 2005 .

[45]  Yang Yang,et al.  High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends , 2005 .

[46]  W. Su,et al.  Small- and Wide-Angle X-ray Scattering Characterization of Bulk Heterojunction Polymer Solar Cells with Different Fullerene Derivatives , 2012 .

[47]  M. Toney,et al.  Charge‐Transport Anisotropy Due to Grain Boundaries in Directionally Crystallized Thin Films of Regioregular Poly(3‐hexylthiophene) , 2009 .

[48]  Thuc‐Quyen Nguyen,et al.  Solvent Additive Effects on Small Molecule Crystallization in Bulk Heterojunction Solar Cells Probed During Spin Casting , 2013, Advanced materials.

[49]  Yongfang Li,et al.  A DMF-assisted solution process boosts the efficiency in P3HT:PCBM solar cells up to 5.31% , 2013, Nanotechnology.

[50]  Wi Hyoung Lee,et al.  Effect of Annealing Solvent Solubility on the Performance of Poly(3-hexylthiophene)/Methanofullerene Solar Cells , 2009 .

[51]  Seok‐In Na,et al.  A morphology controller for high-efficiency bulk-heterojunction polymer solar cells , 2010 .

[52]  F. Krebs,et al.  Stability/degradation of polymer solar cells , 2008 .

[53]  Yanfen Ding,et al.  Controlling the surface composition of PCBM in P3HT/PCBM blend films by using mixed solvents with different evaporation rates , 2013, Chinese Journal of Polymer Science.

[54]  Lionel Hirsch,et al.  P3HT:PCBM, Best Seller in Polymer Photovoltaic Research , 2011, Advanced materials.

[55]  S. Chien,et al.  Nanoscale functional interlayers formed through spontaneous vertical phase separation in polymer photovoltaic devices , 2009 .

[56]  C. Brabec,et al.  2.5% efficient organic plastic solar cells , 2001 .

[57]  Fang‐Chung Chen,et al.  Solvent mixtures for improving device efficiency of polymer photovoltaic devices , 2008 .

[58]  Suren A. Gevorgyan,et al.  Degradation patterns in water and oxygen of an inverted polymer solar cell. , 2010, Journal of the American Chemical Society.

[59]  Craig J. Hawker,et al.  Interdiffusion of PCBM and P3HT Reveals Miscibility in a Photovoltaically Active Blend , 2011 .

[60]  Gang Li,et al.  Effects of Solvent Mixtures on the Nanoscale Phase Separation in Polymer Solar Cells , 2008 .

[61]  M. Dang,et al.  Using volatile additives to alter the morphology and performance of active layers in thin-film molecular photovoltaic devices incorporating bulk heterojunctions. , 2013, Chemical Society reviews.

[62]  Gang Li,et al.  “Solvent Annealing” Effect in Polymer Solar Cells Based on Poly(3‐hexylthiophene) and Methanofullerenes , 2007 .

[63]  Meng-Huan Jao,et al.  Additives for morphology control in high-efficiency organic solar cells , 2013 .

[64]  Argiris Laskarakis,et al.  Evolution of vertical phase separation in P3HT:PCBM thin films induced by thermal annealing , 2011 .