Modelling and electro-optical testing of suspended particle devices

Abstract

a b s t r a c tSome smart windows make use of suspended particle devices (SPDs) which are made of charged rodshape particles that change their orientation in an applied electric field, thereby allowing transmittance control. In this work, the electro-optical behaviour of a commercial SPD is analyzed. Impedance analysis shows characteristics similar to those of a Randles circuit, and a modified equivalent circuit is proposed and experimentally validated. Intermediate levels of transmittance are obtained using a customized field programmable gate array (FPGA)-based electrical circuit. Finally, measurements are taken to check the applicability of the SPD device and control system in smart glazing or photonic applications.

Toward a quantitative model for suspended particle devices: Optical scattering and absorption coefficients

“…We used spectral optical measurements of total and diffuse transmittance and reflectance to characterize a suspended particle device, thereby expanding previous work on electrical characterization of such devices [15,16]. Optical transmission could be modulated within widely separated limits for luminous light, whereas the near-infrared modulation was almost nil.…”

“…The most important of these applications, seen in a global perspective, is the ''smart windows'' that are significant for reducing the energy used in the built environment [4,5] and hence for CO 2 abatement and for combating global warming. The devices enabling modulation of luminous and solar transmittance can be of several different kinds such as electrochromic five-layer ''battery-type'' devices based on inorganic oxides [6][7][8], hydrides [9,10] or on organic materials [11]; suspended-particle devices (SPDs) [12][13][14][15][16]; polymer-dispersed liquid crystals [17,18]; and reversible electroplating systems [19,20]. The least investigated and understood of these seems to be the SPDs, which at first sight is surprising since this type of devices has a venerable history and goes back to the ''light valves'' introduced by Edwin Land in the 1930s and forming the basis of a long series of patents [21].…”

Smart Window Technologies: Electrochromics and Nanocellulose thin film Membranes and Devices

“…Nanoparticles like iron oxide along with nanocellulose may be used to be suspended in liquid/film such as in acetone/silicone oil/propylene carbonate. At no electrical bias, nanoparticles absorb light, making the glass dark [8,9]. On application of bias, particles align and light passes through.…”

Daylight characteristics of a polymer dispersed liquid crystal switchable glazing

“…Comfort Working space [13] 500 Comfortable Office work [14] 500 Comfortable Office work [15] 840-2146 (morning) 840-2146 (morning) Comfortable Office work [4,5,15] 782-1278 (afternoon) 782-1278 (afternoon) Comfortable 700-1800 700-1800 Comfortable Computer work [16] 100-2000 100-2000 Useful Daylight Illuminance Any types of work [12] Switchable glazing includes electrochromic (EC) [17][18][19], gasochromic [20], thermochromic [21], thermotropic [22,23], liquid crystal (LC) [24], suspended particle device (SPD) [25][26][27][28] and phase change materials (PCM) [29]. These glazing can be electrically, thermally, or chemically actuated.…”