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.