Nonradiative Energy Transfer Enables a hv < E_g Response of Perovskite Quantum Dots in Si-Based Inorganic–Organic Hybrid Solar Cells

High performance is a crucial factor in seeking a more competitive levelized cost of electricity for the extensive popularization of c-Si solar cells. Here, CsPbBr 3 quantum dots (QDs) have been first applied as the light-converting layer to enhance the full-spectrum light response, resulting in an ∼71% enhancement of power conversion efficiency within silicon-based solar cells. Remarkably, even if the photon energy is smaller than the bandgap of CsPbBr 3 QDs, the long-wavelength external quantum efficiency shows a significant increase. Such surprising results can be attributed to the nonradiative energy transfer (NRET) mechanism of CsPbBr 3 QDs, which can transfer long-wavelength-generated dipoles into the Si base with the assistance of a Coulomb force. Furthermore, a dipole-transferring model, which considers that the Al 2 O 3 passivation layer would play a negative role in the NRET process, is creatively but supportively proposed. These results highlight a simple, low-cost but promising strategy to improve the performance of c-Si solar cells.