Electrically Controllable Light Trapping for Self-Powered Switchable Solar Windows

The ability to electrically control transparency and scattering of light is important for many optoelectronic devices; however, such versatility usually comes with additional unwanted optical absorption and power loss. Here we present a hybrid switchable solar window device based on polymer dispersed liquid crystals (PDLCs) coupled to a semiconducting absorber, which can switch between highly transmissive and highly scattering states while simultaneously generating power. By applying a voltage across the PDLC layer, the device switches from an opaque, light-scattering structure (useful for room light dimming, privacy, and temperature control) to a clear, transparent window. Further, enabled by the very low operating power requirements of the PDLC (<0.8 mW/cm²), we demonstrate that these switchable solar windows have the potential for self-powering with as little as 13 nm of a-Si.