Harnessing Solar Energy with Organic Photovoltaic Cells

Organic solar cells are currently attracting significant interest due to their potential advantages over traditional inorganic sources, including material diversity, mechanical flexibility, low-temperature processing, and large-area capability. To increase the photovoltaic response of organic solar cells, our efforts aim to address a number of fundamental issues, including: optical absorption and exciton formation; exciton migration to the donor-acceptor interface; exciton dissociation; charge carrier mobility; and charge collection at the electrodes.

We are also particularly interested in donor-acceptor (DA), i.e., low band gap, polymers that have recently garnered considerable use in bulk-heterojunction (BHJ) solar cells because of their wider photon absorption window. These polymers offer the promise of fabricating organic solar cells through solution-processing methods, which can further ease the processing demands and lower production costs. To design materials that improve overall device efficiency, we seek to understand the evolution of the structural, electronic, and optical properties of low band gap polymers that serve as the electron-donor and photon collector in bulk heterojunction solar cells.

Research highlights:
  • Organic Photovoltaics, Kippelen, B; Bredas, JL, Energy & Environmental Science, 2, 251-261 [2009]
  • Recent papers on organic photovoltaic cells:
  • Quantum-Chemical Approach To Electronic Coupling: Application To Charge Separation And Charge Recombination Pathways In A Model Molecular Donor-Acceptor System For Organic Solar Cells, Kawatsu, T; Coropceanu, V; Ye, AJ; Bredas, JL, Journal Of Physical Chemistry C, 112, 3429-3433 [2008]
  • Photoinduced Charge Generation And Recombination Dynamics In Model Donor/Acceptor Pairs For Organic Solar Cell Applications: A Full Quantum-Chemical Treatment, Lemaur, V; Steel, M; Beljonne, D; Bredas, JL; Cornil, J, Journal Of The American Chemical Society, 127, 6077-6086 [2005]
  • Recent papers on low band-gap polymers:
  • Molecular Design For Improved Photovoltaic Efficiency: Band Gap And Absorption Coefficient Engineering, Mondal, R; Ko, S; Norton, JE; Miyaki, N; Becerril, HA; Verploegen, E; Toney, MF; Bredas, JL; McGehee, MD; Bao, ZN, Journal Of Materials Chemistry, 19, 7195-7197 [2009]
  • Synthesis Of Acenaphthyl And Phenanthrene Based Fused-Aromatic Thienopyrazine Co-Polymers For Photovoltaic And Thin Film Transistor Applications, Mondal, R; Miyaki, N; Becerril, HA; Norton, JE; Parmer, J; Mayer, AC; Tang, ML; Bredas, JL; McGehee, MD; Bao, ZA, Chemistry Of Materials, 21, 3618-3628 [2009]
  • A Spray-Processable, Low Bandgap, And Ambipolar Donor-Acceptor Conjugated Polymer, Steckler, TT; Zhang, X; Hwang, J; Honeyager, R; Ohira, S; Zhang, XH; Grant, A; Ellinger, S; Odom, SA; Sweat, D; Tanner, DB; Rinzler, AG; Barlow, S; Bredas, JL; Kippelen, B; Marder, SR; Reynolds, JR, Journal Of The American Chemical Society, 131, 2824 [2009]
  • Optimizing Organic Photovoltaics Using Tailored Heterojunctions: A Photoinduced Absorption Study Of Oligothiophenes With Low Band Gaps, Schueppel, R; Schmidt, K; Uhrich, C; Schulze, K; Wynands, D; Bredas, JL; Brier, E; Reinold, E; Bu, HB; Baeuerle, P; Maennig, B; Pfeiffer, M; Leo, K, Physical Review B, 77, 85311 [2008]