In situ current voltage measurements for optimization of a novel fullerene acceptor in bulk heterojunction photovoltaics

The evaluation of the power conversion efficiency (PCE) of new materials for organic bulk heterojunction (BHJ) photovoltaics is difficult due to the large number of processing parameters possible. An efficient procedure to determine the optimum conditions for thermal treatment of polymer-based bulk heterojunction photovoltaic devices using in situ current-voltage measurements is presented. The performance of a new fullerene derivative, 1,9-dihydro-64,65-dihexyloxy-1,9-(methano[1,2] benzomethano)fullerene[60], in BHJ photovolatics with poly(3-hexylthiophene) (P3HT) was evaluated using this methodology. The device characteristics of BHJs obtained from the in situ method were found to be in good agreement with those from BHJs annealed using a conventional process. This fullerene has similar performance to 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methano fullerene in BHJs with P3HT after thermal annealing. For devices with thickness of 70 nm, the short circuit current was 6.24 mA/cm2 with a fill factor of 0.53 and open circuit voltage of 0.65 V. The changes in the current-voltage measurements during thermal annealing suggest that the ordering process in P3HT dominates the improvement in power conversion efficiency. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

[1]  Frederik C. Krebs,et al.  The OE-A OPV demonstrator anno domini 2011 , 2011 .

[2]  M. Toney,et al.  In situ measurement of power conversion efficiency and molecular ordering during thermal annealing in P3HT:PCBM bulk heterojunction solar cells , 2011 .

[3]  Tao Wang,et al.  The Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend , 2011 .

[4]  A. Heeger,et al.  1,4-Fullerene derivatives: tuning the properties of the electron transporting layer in bulk-heterojunction solar cells. , 2011, Angewandte Chemie.

[5]  Tao Wang,et al.  Evolution of Structure, Optoelectronic Properties, and Device Performance of Polythiophene:Fullerene Solar Cells During Thermal Annealing , 2011 .

[6]  C. Brabec,et al.  Influence of blend microstructure on bulk heterojunction organic photovoltaic performance. , 2011, Chemical Society reviews.

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

[8]  Mikkel Jørgensen,et al.  Ultra fast and parsimonious materials screening for polymer solar cells using differentially pumped slot-die coating. , 2010, ACS applied materials & interfaces.

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

[10]  Yang Yang,et al.  Effect of Carbon Chain Length in the Substituent of PCBM‐like Molecules on Their Photovoltaic Properties , 2010 .

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

[12]  W. Warta,et al.  Solar cell efficiency tables (version 35) , 2010 .

[13]  Klaus Meerholz,et al.  Morphology Control in Solution‐Processed Bulk‐Heterojunction Solar Cell Mixtures , 2009 .

[14]  A. Heeger,et al.  The Role of Processing in the Fabrication and Optimization of Plastic Solar Cells , 2009 .

[15]  Martin Egginger,et al.  Material Solubility‐Photovoltaic Performance Relationship in the Design of Novel Fullerene Derivatives for Bulk Heterojunction Solar Cells , 2009 .

[16]  Amy M. Ballantyne,et al.  Free Energy Control of Charge Photogeneration in Polythiophene/Fullerene Solar Cells: The Influence of Thermal Annealing on P3HT/PCBM Blends , 2008 .

[17]  Bumjoon J. Kim,et al.  The influence of poly(3-hexylthiophene) regioregularity on fullerene-composite solar cell performance. , 2008, Journal of the American Chemical Society.

[18]  Martijn Lenes,et al.  Fullerene Bisadducts for Enhanced Open‐Circuit Voltages and Efficiencies in Polymer Solar Cells , 2008 .

[19]  P. Blom,et al.  Universal arrhenius temperature activated charge transport in diodes from disordered organic semiconductors. , 2008, Physical review letters.

[20]  J. Fréchet,et al.  High efficiency organic photovoltaics incorporating a new family of soluble fullerene derivatives , 2007 .

[21]  Stephen R. Forrest,et al.  Offset energies at organic semiconductor heterojunctions and their influence on the open-circuit voltage of thin-film solar cells , 2007 .

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

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

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

[25]  Xiaoniu Yang,et al.  The Effect of Thermal Treatment on the Morphology and Charge Carrier Dynamics in a Polythiophene–Fullerene Bulk Heterojunction , 2005 .

[26]  Christoph J. Brabec,et al.  Influence of the molecular weight of poly(3-hexylthiophene) on the performance of bulk heterojunction solar cells , 2005 .

[27]  Donal D. C. Bradley,et al.  Device annealing effect in organic solar cells with blends of regioregular poly(3-hexylthiophene) and soluble fullerene , 2005 .

[28]  Valentin D. Mihailetchi,et al.  Effect of metal electrodes on the performance of polymer : fullerene bulk heterojunction solar cells , 2004 .

[29]  S. Holdcroft,et al.  A Phenomenological Model for Predicting Thermochromism of Regioregular and Nonregioregular Poly(3-alkylthiophenes) , 1996 .

[30]  Mario Leclerc,et al.  A calorimetric study of the phase transitions in poly(3-hexylthiophene) , 1995 .