The complemental absorption behavior of donors and acceptors in organic solar cells (OSCs) results in the broad absorption of solar light, contributing to the realization of high-performance OSCs. However, the development of OSCs with narrow absorption ranges, i.e., wavelength-selective OSCs, has made slow progress owing to their limited applications. Here, green-light wavelength-selective OSCs, whose transmitted blue and red light can be effectively used to promote plant growth, are proposed. For the preparation of green-light wavelength-selective OSCs, a practical polymer of poly(3-hexylthiophene) (P3HT) is employed as the donor and naphthobisthiadiazole-based compounds (SNTz-RD and ONTz-RD) are newly designed as the acceptors. The electronic absorption measurements of SNTz-RD and ONTz-RD show strong absorption bands in the green-light region. In addition, SNTz-RD and ONTz-RD possess appropriate frontier orbital energy levels as acceptors. OSCs based on P3HT and these acceptors show typical photovoltaic responses with good green-light wavelength-selective factors and good power conversion efficiencies in the green-light region. Furthermore, the P3HT:SNTz-RD blend films exhibit an improved photosynthetic rate in the strawberry leaves compared to the conventional P3HT:[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) film. These results demonstrate that the combination of P3HT and green-light wavelength-selective acceptors can produce green-light wavelength-selective OSCs for application in new greenhouse agrivoltaics.

The incorporation of electron-accepting units into the π-conjugated systems can allow the modulation of the physical properties and frontier orbital energy levels of the molecules. An electron-accepting π-conjugated compound (CNNTz-TR) containing cyano-substituted naphthobisthiadiazole (CNNTz) was synthesized via a nucleophilic substitution reaction as the key step. Owing to the presence of the cyano groups, CNNTz-TR afforded a low-lying lowest unoccupied molecular orbital energy level. Organic solar cells based on the blend films of CNNTz-TR and a low-bandgap donor exhibited moderate power conversion efficiencies. The result showed that embedding the CNNTz unit into the π-conjugated backbone was an effective approach for designing electron-accepting semiconducting materials.