A dual-band spectral regulation photovoltaic window with unsymmetric emission strategy and infrared filtration capacity

Over the years, researchers have developed numerous spectral-regulation strategies to enhance the performance of building-integrated photovoltaic windows. However, most existing single-band approaches address only single-function (reflection suppression, infrared filtering, low emissivity, or radiative cooling), often resulting in noticeable side-effects or only marginal overall improvements. To overcome these limitations, this study introduces a composite film modification strategy featuring dual-band spectral regulation, enabling more synergistic and comprehensive performance enhancement. In short-wave band, indium tin oxide films are employed to suppress low-frequency photons. In longwave band, the combination of polydimethylsiloxane and silver nanowires enables unsymmetric thermal emission to effectively mitigate heat gain. Preliminary experiments show that the proposed strategy reduces transmitted radiation by 29 %–53 % and cools the surface by up to 4.12 °C, albeit incurring ∼ 17 % power loss. Such drawback due to the unavoidable spectral overlap between infrared filtration and photovoltaic response is identified by numerical simulations as an acceptable trade-off for substantial energy benefits. Further simulations estimate that the proposed strategy can yield energy savings of 60–123 MJ in new buildings and 76–314 MJ in retrofit applications (for high etching ratio cases). These findings highlight its considerable energy-saving potential in cooling-dominated regions and its contribution toward the zero-energy building perspective.