Advanced Energy Materials · 2012 · 389 citations · 50 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsEnergy MaterialsSemiconductor MaterialsEnergy ConversionOrganic Electronic MaterialsOrganic SemiconductorsPhotovoltaic DevicesPhotovoltaic MaterialsSolar CellsDrift-diffusion ModelingMarcus TheoryOrganic Photovoltaic CellsOrganic Photovoltaic MaterialsOrganic PhotovoltaicsOrganic Solar CellsPower ConversionSolar Cell Device Physics
The authors propose three theoretical approaches to achieve organic solar cells with power conversion efficiencies exceeding 20%. They introduce a radiation limit that emphasizes charge‑transfer state absorption, employ a Marcus‑theory model showing that reducing reorganization energies boosts efficiency, and identify the dielectric constant as a key parameter for high performance. The study finds that with sufficiently weak CT action and optimized parameters, efficiencies above 20% are attainable, matching inorganic counterparts.
Abstract Three different theoretical approaches are presented to identify pathways to organic solar cells with power conversion efficiencies in excess of 20%. A radiation limit for organic solar cells is introduced that elucidates the role of charge‐transfer (CT) state absorption. Provided this CT action is sufficiently weak, organic solar cells can be as efficient as their inorganic counterparts. Next, a model based on Marcus theory of electronic transfer that also considers exciton generation in both the electron donor and electron acceptor is used to show how reduction of the reorganization energies can lead to substantial efficiency gains. Finally, the dielectric constant is introduced as a central parameter for efficient solar cells. By using a drift–diffusion model, it is found that efficiencies of more than 20% are within reach.
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