Nano Archive

Photocurrent generation in nanostructured organic solar cells

Yang, Fan and Forrest, Stephen R. (2008) Photocurrent generation in nanostructured organic solar cells. ACS NANO, 2 (5). pp. 1022-1032.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/nn700447t

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 C60. 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.

Item Type:Article
Uncontrolled Keywords:photovoltaics; organic semiconductors; donor-acceptor heterojunction; exciton; charge collection; Monte Carlo simulation
Subjects:Technology > Nanotechnology and energy applications
Material Science > Nanostructured materials
ID Code:5941
Deposited By:IoN
Deposited On:29 Jul 2009 12:12
Last Modified:29 Jul 2009 12:13

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