Abstract: A optical filter comprising a variable transmittance layer having a first spectrum in a dark state, and a second spectrum in a faded state; and a color balancing layer having a third spectrum; each of the first, second and third spectra comprising a visible portion; the first and third spectra combining to provide a dark state spectrum approximating a dark state target color; and the second and third spectra combining to provide a fades state spectrum approximating a faded state target colour. The optical filter may further comprise a light attenuating layer. The optical filter may further comprise part of a laminated glass.

Abstract: A self-powered variable transmittance optical device, such as a smart window or other device, and associated method are provided. The device comprises one or more transparent substrates, with a switching material disposed thereon or therebetween. The switching material may be a hybrid photochromic/electrochromic material capable of transitioning from a first transmittance state to a second transmittance state with application of electricity, and from second state to first state due to another stimulus, such as UV radiation. Electrodes are coupled to the switching material for applying electricity. An electrical system provides for controllable application of the electricity, and may store energy. Energy is provided by an energy-harvesting power source such as a solar cell or other photovoltaic source, or array thereof, or another device for harvesting vibrational or thermal energy.