Multifunctionality of organic devices: Light emission, photovoltage generation, and photodetection

We present multifunctionality in heterostructure devices based on poly(3-hexylthiophene) and copper phthalocyanine layers. Under solar light illumination, the devices yield photovoltage in an open-circuit condition. They, in addition, emit light in the forward bias and can also detect a trace of light in the reverse-bias direction. Highest occupied molecular orbitals and lowest unoccupied molecular orbitals of the two materials, along with the metal work functions, are suitable for the three functionalities at different bias modes. While the electroluminescence spectrum of the device has been compared with the photoluminescence spectra of the components, the spectral response of the photocurrent matched well with the electronic absorption spectrum of the poly(3-hexylthiophene)/copper phthalocyanine heterojunction.