Hybrid inorganic-organic photovoltaic devices are attractive as next generation high efficiency thin film solar cells, but the photovoltaic performance is still low level compared with inorganic solar cells of Si, Cu(InGa)Se2 , and organic solar cells of C60.
With this background it is necessary to investigate the fundamental aspects of these materials including the molecular configuration, energy state, and band alignment to improve photovoltaic performance.
In new work (“Hybrid Cu2O Diode with Orientation-Controlled C60 Polycrystal”), Masanobu Izaki and colleagues fabricated hybrid p-Cu2O/C60 photovoltaic device on -oriented Au -coated Si substrates by electro-deposition of Cu2O layer followed by vacuum evaporation of the C60 layers as an acceptor layer.
FE-SEM image of the cross-section of the hybrid p-Cu2O/C60/BCP photovoltaic device and schematic illustrations of Cu2O and C60 structures.
The C60 layers exhibited face centered cubic molecular configuration on the -oriented Cu2O layer, and the preferred orientation changed from random to plane depending on the preparation methods.
The electrical characteristics of hybrid photovoltaic devices varied depending on the C60 molecular configuration, and a rectification characteristic with an ideality factor of approximately 1 was achieved for hybrid -Cu2O/-fcc- C60/ bath cuproine photovoltaic devices.
This research underscores the importance not only of the configuration of both organic and inorganic semiconductors but also of the introduction of nanostructures in the light-absorbing layer and optimization of the band alignment at the heterointerface in hybrid photovoltaic devices.
Source: Toyohashi University of Technology
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