Application of quantitative prediction to design new organic dyes in dye sensitized solar cells

Two new groups, cyclopentadipyrrole and dihydropyrroloindole, that has been applied for other relevant regions, are firstly employed as pi group to compose the organic dyes, (E)-3-(6-(10-butyl-10H-phenothiazin-2-yl)-4,4-dimethyl-4,7-dihydro-1H-cyclopenta [2,1-b:3,4-b']dipyrrol-2-yl)-2-cyanoacrylic acid (PCP3) and (E)-3-(7-(10-butyl-10H-phenothiazin-2-yl)-1,8-dihydropyrrolo[3,2-g]indol-2-yl)-2-cyanoacrylic acid (PBP4), in DSSCs along with phenothiazine as donor and cyanoacrylic acid as acceptor. Their performance should be screened out before it would be fabricated in device. When the frontier molecular orbitals (FMO) and absorption spectrum properties are studied, the performance of PCP3 and PBP4 is not better than that of (E)-3-(6-(10-butyl-10H-phenothiazin-2-yl)-4,4-dimethyl-4H-cyclopenta[2,1-b:3,4-b']dithiophen-2-yl)-2-cyanoacrylic acid (PCT1) and (E)-3-(7-(10-butyl-10H-phenothiazin-2-yl)benzo[2,1-b:3,4-b']dithiophen-2-yl)-2-cyanoacrylic acid (PBT2). Even when the dye-TiO2 adsorbed system is considered, the differences among four organic dyes are too small to distinguish them, which is also perplex for most of theoretical studies. To have a reliable and accurate results, the values of short-circuit current density (J(SC)), open-circuit voltage (V-OC), and photon-to-electron conversion efficiency (PCE) for DSSCs on the basis of four organic dyes are accurately determined. Although the J(SC) of PCP3 is the smaller than that of PCT1, the PCE of PCP3 is comparable with that of PCT1 due to the larger V-OC. The quantitative calculation is an effective method to make a distinction among every designed dyes. (C) 2019 Elsevier B.V. All rights reserved.