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feature advantages, such as light weight, low-cost, flexibility, solution-processability, and feasibility of easy and large-area fabrication, have drawn considerable attentions recently. [1-7] In the last three years, although OPV developed rapidly with power conversion efficiencies (PCEs) up to 16-17%, [8-14] it still cannot compete with inorganic PVs (such as silicon, Cu(In, Ga)Se 2 , and GaAs) which hold PCEs of 23-28%. [15] However, thanks to the nature of molecular orbitals, the absorption spectra of organic semiconductors are not continuous as those in traditional inorganic semiconductors, and this characteristic offers a unique application of OPVs: semitransparent OPVs. The concept of semitransparent OPVs was first reported by our group [16] and Forrest and co-workers [17] in 2006. Semitransparent OPVs are OPV devices with semitransparent absorption spectrum in the visible region (400-700 nm), and they show great potentials for future applications. [18-20] For example, they can be equipped in agricultural greenhouses, or can be used as building-integrated photovoltaics. At the early stage (2006-2016) of semitransparent OPVs' development, their active layers were based on medium-or narrow-bandgap polymer donor/[6,6]-phenyl-C61-butyric acid methyl ester