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Photovoltaic cells based on nickel phthalocyanine and zinc oxide formed by atomic layer deposition
|Pavlo Stakhira 1, Grzegorz Łuka 2, Georgiy Pakhomov 3, Dmytro Volynyuk 1, Vladyslav Cherpak 1, Marek Godlewski 2,4, Elżbieta Guziewicz 2, Zenon Hotra 1,5|
1. Lviv Polytechnic National University, 12 Bandera, Lviv 79013, Ukraine
Recent progress in organic solar cells is associated, in most cases, with utilization of the layered (or bulk) heterojunctions, as well as with development of packaging technologies. This particularly concerns various prototypes of solar cells employing phthalocyanines (Pc) as photoactive materials. Here, due to high sensitivity of these compounds to absorbed gases (sensitivity of electrical parameters of solids or thin films, but not molecular destruction), isolation from atmosphere is highly desired. Additionally, problems arise at the top interface between Pc layer and metallic electrode. The device life time suffers much from instability of this interface, which can roughly be divided into chemical (possible reactions, diffusion of components etc.) and physical degradation, i.e. alteration in barrier properties.
One of the ways to solve these problems is insertion of an ultrathin layer, organic or inorganic, before depositing top contact. This may either prevent penetration of admixtures into Pc layer or facilitate injection of charge carriers from the contact, or both. The present work investigates the effect of introduction of zinc oxide (ZnO) ultrathin layer on the efficiency of photovoltaic cells based on nickel phthalocyanine (NiPc). Introduction of ultrathin ZnO layer formed by the atomic layer deposition (ALD) technique was found to markedly improve the parameters of nickel phthalocyanine (NiPc) based photovoltaic cells. This improvement is attributed to an increase in both rectifying and photovoltaic activity in the ITO/NiPc/ZnO/Al cells incorporating a hybrid heterojunction as compared with the single-layer ITO/NiPc/Al cells, to enhancement of the overall spectral response in the double-layer cells and to extension of their long-term operational stability.
Presentation: Oral at E-MRS Fall Meeting 2009, Symposium C, by Grzegorz Łuka
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-08 16:25 Revised: 2009-06-07 00:48