The anchoring group is an important part of the solar cell organic sensitizers because it should link the dye strongly to the semiconductor surface. Commonly, dyes are grafted onto the semiconductor surface through carboxylic acid function. However, irradiation over long periods can provoke a release of the dyes bound to the semiconductor surface through COOH anchors. Therefore, alternative functional groups for binding dyes onto TiO 2 have been examined. Tetrazole with having the ability of coordination with the cations can be used as anchoring group for sensitizers. Here, the synthesis of new sensitizers with anchoring groups based on tetrazole was reported. The compounds ethyl 2-(1 H -tetrazol-5-yl) acetate, (2 H -tetrazol-5-yl) acrylonitrile and 1 H -tetrazole-5-acetic acid was used as anchoring groups and the dye with (2 H -tetrazol-5-yl) acrylonitrile showed the best photovoltaic properties. The antenna effect also was considered in the dyes with ethyl 2-(1 H -tetrazol-5-yl) acetate anchoring group. Diphenylamine group was the best antenna in the synthesized dyes. The structure of these dyes was modified with additional anchoring group and the dyes with double anchoring group were also synthesized. The measurements of photovoltaic properties of the solar cell based on these dyes showed that the organic dyes with two electron acceptor groups gave higher performance than their counterparts of single electron acceptor type. In the theoretical section, the complexation of two cyclic peptides with the alkali and earth alkali cations was studied. As the general result, the smallest cations bind strongly to the cyclic peptides.
