Geometric light trapping with a V-trap for efficient organic solar cells.

The efficiency of today's most efficient organic solar cells is primarily limited by the ability of the active layer to absorb all the sunlight. While internal quantum efficiencies exceeding 90% are common, the external quantum efficiency rarely exceeds 70%. Light trapping techniques that increase the ability of a given active layer to absorb light are common in inorganic solar cells but have only been applied to organic solar cells with limited success. Here, we analyze the light trapping mechanism for a cell with a V-shape substrate configuration and demonstrate significantly improved photon absorption in an 5.3%-efficient PCDTBT:PC(70)BM bulk heterojunction polymer solar cell. The measured short circuit current density improves by 29%, in agreement with model predictions, and the power conversion efficiency increases to 7.2%, a 35% improvement over the performance in the absence of a light trap.

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

[2]  A. Gombert,et al.  Functional microprism substrate for organic solar cells , 2006 .

[3]  C. Brabec,et al.  Angle dependence of external and internal quantum efficiencies in bulk-heterojunction organic solar cells , 2007 .

[4]  Yang Yang,et al.  Polymer solar cells with enhanced open-circuit voltage and efficiency , 2009 .

[5]  Gang Li,et al.  Synthesis of a low band gap polymer and its application in highly efficient polymer solar cells. , 2009, Journal of the American Chemical Society.

[6]  Volker Wittwer,et al.  Diffraction gratings and buried nano-electrodes—architectures for organic solar cells , 2004 .

[7]  L. S. Roman,et al.  Modeling photocurrent action spectra of photovoltaic devices based on organic thin films , 1999 .

[8]  Xiong Gong,et al.  New Architecture for High‐Efficiency Polymer Photovoltaic Cells Using Solution‐Based Titanium Oxide as an Optical Spacer , 2006 .

[9]  Viktor Andersson,et al.  Optical modeling of a folded organic solar cell , 2008 .

[10]  M. Green.  Enhanced evanescent mode light trapping in organic solar cells and other low index optoelectronic devices , 2011 .

[11]  Nils-Krister Persson,et al.  Comparative study of organic thin film tandem solar cells in alternative geometries , 2008 .

[12]  Xiangang Luo,et al.  Efficiency Enhancement of Organic Solar Cells Using Transparent Plasmonic Ag Nanowire Electrodes , 2010, Advanced materials.

[13]  Olle Inganäs,et al.  Trapping light with micro lenses in thin film organic photovoltaic cells. , 2008, Optics express.

[14]  Luca Businaro,et al.  Light confinement in thin film organic photovoltaic cells , 2006, SPIE Photonics Europe.

[15]  Jung-Yong Lee,et al.  The origin of enhanced optical absorption in solar cells with metal nanoparticles embedded in the active layer. , 2010, Optics express.

[16]  Zongfu Yu,et al.  Dielectric nanostructures for broadband light trapping in organic solar cells , 2011, CLEO: 2011 - Laser Science to Photonic Applications.

[17]  A J Heeger,et al.  Efficiency enhancement in low-bandgap polymer solar cells by processing with alkane dithiols. , 2007, Nature materials.

[18]  Yi Cui,et al.  Plasmonic Dye‐Sensitized Solar Cells , 2014 .

[19]  Mario Leclerc,et al.  A Low‐Bandgap Poly(2,7‐Carbazole) Derivative for Use in High‐Performance Solar Cells , 2007 .

[20]  Peter Peumans,et al.  An effective light trapping configuration for thin-film solar cells , 2007 .

[21]  Shanhui Fan,et al.  Enhancement of optical absorption in thin-film organic solar cells through the excitation of plasmonic modes in metallic gratings , 2010 .

[22]  Stephen R. Forrest,et al.  Efficient photon harvesting at high optical intensities in ultrathin organic double-heterostructure photovoltaic diodes , 2000 .

[23]  Ludovic Escoubas,et al.  Improving light absorption in organic solar cells by plasmonic contribution , 2009 .

[24]  Olle Inganäs,et al.  Full day modelling of V-shaped organic solar cell , 2011 .

[25]  Viktor Andersson,et al.  Folded reflective tandem polymer solar cell doubles efficiency , 2007 .

[26]  Christoph J. Brabec,et al.  Performance improvement of organic solar cells with moth eye anti-reflection coating , 2008 .

[27]  Lei Zhang,et al.  Photonic crystal geometry for organic solar cells. , 2009, Nano letters.

[28]  Xing Wang Zhang,et al.  Plasmonic polymer tandem solar cell. , 2011, ACS nano.

[29]  Mats Andersson,et al.  Trapping light in polymer photodiodes with soft embossed gratings , 2000 .

[30]  S. Wenham,et al.  Absorption enhancement in conformally textured thin-film silicon solar cells , 1996, Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996.

[31]  D. Ginger,et al.  Plasmon-enhanced charge carrier generation in organic photovoltaic films using silver nanoprisms. , 2010, Nano letters.

[32]  Valentin D. Mihailetchi,et al.  Light intensity dependence of open-circuit voltage of polymer: fullerene solar cells , 2005 .