Role of the Metal-Oxide Work Function on Photocurrent Generation in Hybrid Solar Cells

Abstract ZnO is a widely used metal-oxide semiconductor for photovoltaic application. In solar cell heterostructures they not only serve as a charge selective contact, but also act as electron acceptor. Although ZnO offers a suitable interface for exciton dissociation, charge separation efficiencies...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Chawloon Thu, Philipp Ehrenreich, Ka Kan Wong, Eugen Zimmermann, James Dorman, Wei Wang, Azhar Fakharuddin, Martin Putnik, Charalampos Drivas, Aimilios Koutsoubelitis, Maria Vasilopoulou, Leonidas C. Palilis, Stella Kennou, Julian Kalb, Thomas Pfadler, Lukas Schmidt-Mende
Formato: article
Lenguaje:EN
Publicado: Nature Portfolio 2018
Materias:
R
Q
Acceso en línea:https://doaj.org/article/de3a11d041e94e7faa0f58b13c58ba09
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
Descripción
Sumario:Abstract ZnO is a widely used metal-oxide semiconductor for photovoltaic application. In solar cell heterostructures they not only serve as a charge selective contact, but also act as electron acceptor. Although ZnO offers a suitable interface for exciton dissociation, charge separation efficiencies have stayed rather poor and conceptual differences to organic acceptors are rarely investigated. In this work, we employ Sn doping to ZnO nanowires in order to understand the role of defect and surface states in the charge separation process. Upon doping we are able to modify the metal-oxide work function and we show its direct correlation with the charge separation efficiency. For this purpose, we use the polymer poly(3-hexylthiophene) as donor and the squaraine dye SQ2 as interlayer. Interestingly, neither mobilities nor defects are prime performance limiting factor, but rather the density of available states around the conduction band is of crucial importance for hybrid interfaces. This work highlights crucial aspects to improve the charge generation process of metal-oxide based solar cells and reveals new strategies to improve the power conversion efficiency of hybrid solar cells.