title: Photocurrent generation in nanostructured organic solar cells.
abstract: Photocurrent generation in nanostructured organic solar cells is simulated using a dynamical Monte Carlo model that includes the generation and transport properties of both excitons and free charges. Incorporating both optical and electrical properties, we study the influence of the heterojunction nanostructure (e.g., planar vs bulk junctions) on donor-acceptor organic solar cell efficiencies based on the archetype materials copper phthalocyanine (CuPc) and C(60). Structures considered are planar and planar-mixed heterojunctions, homogeneous and phase-separated donor-acceptor (DA) mixtures, idealized structures composed of DA pillars, and nanocrystalline DA networks. The thickness dependence of absorption, exciton diffusion, and carrier collection efficiencies is studied for different morphologies, yielding results similar to those experimentally observed. The influences of charge mobility and exciton diffusion length are studied, and optimal device thicknesses are proposed for various structures. Simulations show that, with currently available materials, nanocrystalline network solar cells optimize both exciton diffusion and carrier collection, thus providing for highly efficient solar energy conversion. Estimations of achievable energy conversion efficiencies are made for the various nanostructures based on current simulations used in conjunction with experimentally obtained fill factors and open-circuit voltages for conventional small molecular weight materials combinations.
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Forrest
mesh_terms: D017076:Computer-Aided Design; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D009930:Organic Chemicals / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D010777:Photochemistry / Q000295:instrumentation*; D012993:Solar Energy
chemical_list: D009930:Organic Chemicals