Exact analytical solution of a two diode circuit model for organic solar cells showing S-shape using Lambert W-functions

Organic solar cells (OSCs) often show a kink, also called S-shape, in the current-voltage (I-V) characteristics, that has been attributed to different physical phenomena such as poor quality of cathode-active layer interface or unbalance charge carrier mobilities. This non-ideal behaviour can be ele...

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Detalhes bibliográficos
Autores: Romero, Beatriz, Pozo, Gonzalo del, Arredondo, Belén
Tipo de documento: artigo
Data de publicação:2012
País:España
Recursos:Universidad Rey Juan Carlos
Repositório:BURJC-Digital. Repositorio Institucional de la Universidad Rey Juan Carlos
OAI Identifier:oai:burjcdigital.urjc.es:10115/12030
Acesso em linha:http://hdl.handle.net/10115/12030
Access Level:Acceso aberto
Palavra-chave:Organic solar cells
Equivalent circuit
S-shape
W-Lambert
3307 Tecnología Electrónica
3306.02 Aplicaciones Eléctricas
Descrição
Resumo:Organic solar cells (OSCs) often show a kink, also called S-shape, in the current-voltage (I-V) characteristics, that has been attributed to different physical phenomena such as poor quality of cathode-active layer interface or unbalance charge carrier mobilities. This non-ideal behaviour can be electrically modelled including a second diode, in reverse bias, together with an extra shunt resistance (R-P2) in the traditional solar cell equivalent circuit. In this paper, we solve without approximations the transcendental equation system derived from this modified circuit. We have obtained an analytical expression for I-V curves decoupling the voltage drop in each diode using Lambert W function. This expression has been fitted to experimental data in order to obtain circuital parameters. Simulations varying saturation current of reverse diode (I-02) and R-P2 have been performed in order to study the dependence of S-shape with these parameters.