High-efficiency organic solar cells with low non-radiative recombination loss and low energetic disorder

Energy loss within organic solar cells (OSCs) is undesirable as it reduces cell efficiency 1 – 4 . In particular, non-radiative recombination loss 3 and energetic disorder 5 , which are closely related to the tail states below the band edge and the overall photon energy loss, need to be minimized to improve cell performance. Here, we report how the use of a small-molecule acceptor with torsion-free molecular conformation can achieve a very low degree of energetic disorder and mitigate energy loss in OSCs. The resulting single-junction OSC has an energy loss due to non-radiative recombination of just 0.17 eV and a high power conversion efficiency of up to 16.54% (certified as 15.89% by the National Renewable Energy Laboratory). The findings take studies of organic photovoltaics deeper into a new regime, beyond the limits of energetic disorder and large energy offset for charge generation. An organic solar cell designed with minimal energetic disorder exhibits very low energy loss due to non-radiative recombination and highly efficient operation.

[1]  D. Neher,et al.  Emissive and charge-generating donor–acceptor interfaces for organic optoelectronics with low voltage losses , 2019, Nature Materials.

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

[3]  Wenkai Zhong,et al.  Achieving over 16% efficiency for single-junction organic solar cells , 2019, Science China Chemistry.

[4]  K. Yoshikawa,et al.  Silicon heterojunction solar cell with interdigitated back contacts for a photoconversion efficiency over 26% , 2017, Nature Energy.

[5]  M. Stutzmann,et al.  Thermodynamic Efficiency Limit of Molecular Donor‐Acceptor Solar Cells and its Application to Diindenoperylene/C60‐Based Planar Heterojunction Devices , 2012 .

[6]  P. Blom,et al.  Trap-assisted recombination in disordered organic semiconductors. , 2011, Physical review letters.

[7]  Christopher M. Proctor,et al.  Understanding Open‐Circuit Voltage Loss through the Density of States in Organic Bulk Heterojunction Solar Cells , 2016 .

[8]  F. Urbach.  The Long-Wavelength Edge of Photographic Sensitivity and of the Electronic Absorption of Solids , 1953 .

[9]  Thomas Kirchartz,et al.  What Makes a Good Solar Cell? , 2018 .

[10]  Feng Gao,et al.  Organic solar cells based on non-fullerene acceptors. , 2018, Nature materials.

[11]  James C. Blakesley,et al.  Relationship between energetic disorder and open-circuit voltage in bulk heterojunction organic solar cells , 2011 .

[12]  Jie Zhu,et al.  Over 14% Efficiency in Polymer Solar Cells Enabled by a Chlorinated Polymer Donor , 2018, Advanced materials.

[13]  Thomas Kirchartz,et al.  Recombination via tail states in polythiophene:fullerene solar cells , 2011 .

[14]  J. Bisquert,et al.  Influence of the Intermediate Density-of-States Occupancy on Open-Circuit Voltage of Bulk Heterojunction Solar Cells with Different Fullerene Acceptors , 2010 .

[15]  J. Nelson,et al.  Nonradiative Energy Losses in Bulk-Heterojunction Organic Photovoltaics , 2018, Physical Review X.

[16]  Thomas Kirchartz,et al.  Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells , 2012 .

[17]  H. Ade,et al.  Fast charge separation in a non-fullerene organic solar cell with a small driving force , 2016, Nature Energy.

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

[19]  He Yan,et al.  Design rules for minimizing voltage losses in high-efficiency organic solar cells , 2018, Nature Materials.

[20]  Uwe Rau,et al.  Reciprocity relation between photovoltaic quantum efficiency and electroluminescent emission of solar cells , 2007 .

[21]  Thomas Kirchartz,et al.  Optical Gaps of Organic Solar Cells as a Reference for Comparing Voltage Losses , 2018, Advanced Energy Materials.

[22]  Jacek Ulanski,et al.  Single-Junction Organic Solar Cell with over 15% Efficiency Using Fused-Ring Acceptor with Electron-Deficient Core , 2019, Joule.

[23]  F. Gao,et al.  Over 16% efficiency organic photovoltaic cells enabled by a chlorinated acceptor with increased open-circuit voltages , 2019, Nature Communications.

[24]  David Beljonne,et al.  Approaching disorder-free transport in high-mobility conjugated polymers , 2014, Nature.

[25]  D. Neher,et al.  Reducing Voltage Losses in Cascade Organic Solar Cells while Maintaining High External Quantum Efficiencies , 2017 .

[26]  Juan Bisquert,et al.  Open-circuit voltage limit caused by recombination through tail states in bulk heterojunction polymer-fullerene solar cells , 2010 .

[27]  Yong Cao,et al.  Organic and solution-processed tandem solar cells with 17.3% efficiency , 2018, Science.

[28]  Eli Yablonovitch,et al.  Strong Internal and External Luminescence as Solar Cells Approach the Shockley–Queisser Limit , 2012, IEEE Journal of Photovoltaics.

[29]  R. Friend,et al.  Order enables efficient electron-hole separation at an organic heterojunction with a small energy loss , 2018, Nature Communications.

[30]  Yang Yang,et al.  Next-generation organic photovoltaics based on non-fullerene acceptors , 2018 .

[31]  Thomas Kirchartz,et al.  Open-Circuit Voltages Exceeding 1.26 V in Planar Methylammonium Lead Iodide Perovskite Solar Cells , 2018, ACS Energy Letters.

[32]  Tom Markvart,et al.  Solar cell as a heat engine: energy–entropy analysis of photovoltaic conversion , 2008 .

[33]  Fujun Zhang,et al.  Conformation Locking on Fused‐Ring Electron Acceptor for High‐Performance Nonfullerene Organic Solar Cells , 2018 .

[34]  R. Friend,et al.  Organic solar cells based on non-fullerene acceptors. , 2018, Nature materials.

[35]  Thuc‐Quyen Nguyen,et al.  Harvesting the Full Potential of Photons with Organic Solar Cells , 2016, Advanced materials.

[36]  M. Gruber,et al.  Quantification of energy losses in organic solar cells from temperature-dependent device characteristics , 2013 .

[37]  Feng Liu,et al.  Single-junction polymer solar cells with high efficiency and photovoltage , 2015, Nature Photonics.

[38]  Thomas Kirchartz,et al.  Quantifying Losses in Open-Circuit Voltage in Solution-Processable Solar Cells , 2015 .

[39]  Yuan Zhang,et al.  Effects of Nonradiative Losses at Charge Transfer States and Energetic Disorder on the Open‐Circuit Voltage in Nonfullerene Organic Solar Cells , 2018 .

[40]  J. Nelson,et al.  Meaning of reaction orders in polymer:fullerene solar cells , 2012 .

[41]  Thomas Kirchartz,et al.  Efficiency Potential of Photovoltaic Materials and Devices Unveiled by Detailed-Balance Analysis , 2017 .