Regarding the light-to-energy conversion efficiency, it has been known to be controlled mainly by several components including the TiO 2 film, the dye, the electrolyte, and the counter electrodes. In the past few decades, a vast effort has been dedicated to the development of related components, seeking to increase the conversion efficiency of DSSCs. However, after these studies, the conversion efficiency under one sun illumination only increased a little bit from about 11% to 14%. [2][3][4][5] Recently, the applications of DSSC on dim light environments has drawn more and more attention, which is due to not only the slow progress in achieving satisfactory efficiency under sun-light illumination, but also the high efficiency achieved under the indoor light environment. [6] Furthermore, due to the rapid growth of the Internet of Things (IoT), more and more attention has been paid to recovering the indoor light into electric energy to supply energy for low-power consumption devices such as sensors, actuators, health care devices, portable electronics, sustainable smart housing, etc., fulfilling the self-energy supplier and wireless IoT system. [7] DSSCs operating under indoor light conditions have been termed as dye-sensitized indoor photovoltaics (DSiPVs); and the conversion efficiencies of DSiPVs are much higher than those of DSSCs under sun-light illumination. [8] One of the reasons for this is attributed to the narrower wavelength region of the indoor lights, including the light-emitting diode (LED), fluorescence lighting, and other artificial lights. Since the illumination light is low for indoor light, the conditions utilized to gain high cell efficiencies may differ from those for sunlight conditions. It has been found, for DSiPVs operating under dim light, that electrolytes prepared using a 3-methoxy propionitrile (MPN) solvent can get higher cell efficiencies than those using acetonitrile (ACN) solvent; this phenomenon is different from the solvent effect under sun-light illumination. [9,10] Furthermore, because a relatively small number of electrons are excited under room light conditions, lower concentrations of redox couple are required to recover the holes. The optimal redox for dim light operation is lower than that for sun-light environmental. [9][10][11] One of the other factors determining the performance of indoor To prepare bifacial dye-sensitized solar cells (DSSCs), the classical photoelectrode employing the main light-absorbing layer (ML) and scattering layer (SL) will encounter the scattering effect of SL to the rear-side incident light and, thereby, decrease the rear-side efficiencies. To solve this problem, the SL has always been removed for the fabrication of bifacial cells. However, the front-side efficiency decreases without the SL. Here, a novel structure of a TiO 2 photoelectrode is developed for bifacial DSSCs to solve the contrary effect for cells with and without an SL, increasing both the front-side and rear-side efficiencies. This new structure is constructed by introducing an add...