Single and Multi-Junction Organic Solar Cells

The power conversation efficiency (PCE) of organic photovoltaics (OPVs) has been advancing rapidly in recent years with record values now exceeding 17 and 18% for multi- and single-junction OPVs, respectively. Despite the tremendous progress, however, several scientific and technological challenges still remain. This project aims to address some of these key challenges and demonstrate highly-efficient single cells and monolithic organic/organic tandem solar cells with PCE >20%. The work builds on our recent efforts towards advanced bulk-heterojunction (BHJ) systems, molecular dopants and new interlayer materials. Our recent studies indicate that single junction OPVs incorporating optimal combinations of materials can yield efficiency values in excess of 20%, whilst for tandem cells this upper efficiency limit exceeds 25%. The experimental efforts will be supported by theoretical calculations of the materials interactions and photonic structure of the cells, as well as transient laser spectroscopy measurements to elucidate the key loss processes that would need to be mitigated in order to achieve ultimate performance. 

Notable research accomplishments

  1. S. Alsaggaf et al., Efficiency Limits in Wide‐Bandgap Ge‐Containing Donor Polymer: Non‐Fullerene Acceptor Bulk Heterojunction Solar Cells, physica status solidi (RRL)–Rapid Research Letters 2021, doi: 10.1002/pssr.202100206.
  2. J.I. Khan et al., Impact of Acceptor Quadrupole Moment on Charge Generation and Recombination in Blends of IDT‐Based Non‐Fullerene Acceptors with PCE10 as Donor Polymer, Advanced Energy Materials 2021, 2100839.
  3. Y. Lin et al., 18.4% Organic Solar Cells Using a High Ionization Energy Self‐Assembled Monolayer as Hole Extraction Interlayer. ChemSusChem 2021, ChemSusChem 10.1002/cssc.202100707.
  4. N. Sakai et al., Adduct-based p-doping of organic semiconductors, Nature Materials 2021, https://doi.org/10.1038/s41563-021-00980-x.
  5. S. Karuthedath et al., Intrinsic efficiency limits in low-bandgap non-fullerene acceptor organic solar cells, Nature Materials 2021, 20, 378.
  6. Y. Firdaus et al., Efficient Double-and Triple-Junction Nonfullerene Organic Photovoltaics and Design Guidelines for Optimal Cell Performance, ACS Energy Letters, 2021, 5, 3692.
  7. Y. Lin et al., A simple n-dopant derived from diquat boosts the efficiency of organic solar cells to 18.3%, ACS Energy Letters 2020, 5, 3663.
  8. Y. Firdaus et al., Long-range exciton diffusion in molecular non-fullerene acceptors, Nature Communications 2020, 11, 5220.
  9. Y. Lin et al., Self-assembled monolayer enables hole transport layer-free organic solar cells with 18% efficiency and improved operational stability, ACS Energy Letters 2020, 5, 2935.
  10. C. H. Y. Ho et al., High‐Performance Tandem Organic Solar Cells Using HSolar as the Interconnecting Layer, Advanced Energy Materials 2020, 10, 2000823.
  11. E. Dauzon et al., Stretchable and Transparent Conductive PEDOT: PSS‐Based Electrodes for Organic Photovoltaics and Strain Sensors Applications, Advanced Functional Materials 2020, 30, 2001251.
  12. Y. Lin et al., 17.1% Efficient Single‐Junction Organic Solar Cells Enabled by n‐Type Doping of the Bulk‐Heterojunction, Advanced Science 2020, 7, 1903419.
  13. Y. Lin et al., 17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS2 as a Replacement for PEDOT:PSS, Advanced Materials 2020, 31, 1902965.
  14. Q. Fan et al., Over 14% efficiency all-polymer solar cells enabled by a low bandgap polymer acceptor with low energy loss and efficient charge separation, Energy & Environmental Science 2020, 13, 5017.
  15. Y. Firdaus et al., Key Parameters Requirements for Non‐Fullerene‐Based Organic Solar Cells with Power Conversion Efficiency> 20%, Advanced Science 2020, 6, 1802028.