Prof. Fang-Chung Chen and his research team calculate the Shockley-Queisser limits under indoor light sources and reveal an unusual bandgap (Eg) zone, in which the dependence of the power conversion efficiencies (PCEs) on the value of Eg under illumination from the indoor lighting sources exhibited different trends from that under solar irradiation; this result runs counter to a common intuition. Following the calculation results, they enlarge the Eg of perovskite materials, thereby increasing the PCEs of perovskite solar cells under indoor lighting conditions. He foresees a high efficiency up to ~60% can be achieved theoretically. This work has been published in Advanced Energy Materials and selected as inside Front Cover.