FUNCTIONAL TUNING OF PHOTOCAPACITORS BY OPTIMIZATION OF LAYERS THICKNESSES
Aleksandar Opančar1, Anja Mioković1, Marta Nikić1, Vedran Đerek1
1 Department of Physics, Faculty of Science, University of Zagreb, Zagreb, Croatia
Organic electronic devices are often made from PN bilayers of organic molecules that exhibit P or N-type photoconductive behavior when exposed to light. Such devices can be made as photodiodes for photocurrent generation or as photocapacitors for stimulation in bioelectronic and electrophysiological applications. In both cases, layer thicknesses are crucial parameters to consider for a highly functional device. In this work, we observe how the thickness of each layer affects the performance of a photocapacitor based on metal-free phthalocyanine (H2PC) and N,N′-dimethyl perylenetetracarboxylic diimide (PTCDI) as active materials. We consider maximum current and voltage characteristics as well as time constants of charging and discharging transients. We propose some probable signs of layers being too thick or thin as well as some specific application where such characteristics might be favorable. Although our findings are based on one type of device, some conclusions may be more general and applicable to other bilayer organic semiconductor-based electronics.
Acknowledgements: This work has been supported by the Croatian Science Foundation under the project 3Doptobio UIP-2019-04-1753 and the project CeNIKS, co-financed by the Croatian Government and the European Union through the European Regional Development Fund – Competitiveness and Cohesion Operational Programme (grant no. KK.01.1.1.02.0013), and the QuantiXLie Center of Excellence, a project co-financed by the Croatian Government and European Union through the European Regional Development Fund – the Competitiveness and Cohesion Operational Programme (grant no. KK.01.1.1.01.0004). Financial support by the Center of Excellence for Advanced Materials and Sensors, Croatia, is gratefully acknowledged.
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