Optical performance and color investigations of hybrid solar cells based on P3HT:ZnO, PCPDTBT:ZnO, PTB7:ZnO and DTS(PTTh2)2:ZnO

Spectroscopic ellipsometry has been used to extract the optical indices of blend organic donor:ZnO (1:2) thin films. Four different donor molecules are investigated in this study: P3HT, PCPDTBT, PTB7 and DTS (PTTh2)(2). Using these optical indices as input parameters, the optical performances and the color range for human eyes of donor:ZnO (1:2) hybrid organic-inorganic solar cells have been investigated through optical simulations. These calculations suggest that a tradeoff between reflectance for human eyes and photonic absorption of the AM1.5 spectrum can be reached depending on the composition of the active layer. While the total device reflectance in the visible range is closely correlated to the photonic absorption in the case of a high band gap semiconducting material, a tradeoff is easier to obtain in the case of low band gap semi-conducting materials. Finally, we show that the color range of devices depends both on the active layer compositions and the geometrical parameters of the cells. (C) 2014 Elsevier B.V. All rights reserved.