A wide-gap a-SiC:H PV-powered electrochromic window coating

Conference · Tue Sep 01 04:00:00 EDT 1998

OSTI ID:305636

Gao, W; Lee, S H; Xu, Y; Benson, D K; Deb, S K; Branz, H M ^[1]

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1. National Renewable Energy Lab., Golden, CO (United States)

The authors report on the first monolithic, amorphous-silicon-based, photovoltaic-powered electrochromic window coating. The coating employs a wide bandgap a-Si{sub 1{minus}x}C{sub x}:H n-i-p photovoltaic (PV) cell as a semitransparent power supply, and a Li{sub y}WO{sub 3}/LiAlF{sub 4}/V{sub 2}O{sub 5} electrochromic (EC) device as an optical-transmittance modulator. The EC device is deposited directly on top of a PV cell that coats a glass substrate. The a-Si{sub 1{minus}x}C{sub x}:H PV cell has a Tauc gap of 2.2 eV and a transmittance of 60--80% over a large portion of the visible light spectrum. The authors reduced the thickness of the device to about 600 {angstrom} while maintaining a 1-sun open-circuit voltage of 0.9 V and short-circuit current of 2 mA/cm{sup 2}. The prototype 16 cm{sup 2} PV/EC device modulates the transmittance by more than 60% over a large portion of the visible spectrum. The coloring and bleaching times of the EC device are approximately 1 minute under normal operating conditions ({+-} 1 volt). A brief description of photoelectrochromic windows study is also given.

• Research Organization: National Renewable Energy Lab., Golden, CO (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC36-83CH10093
• OSTI ID: 305636
• Report Number(s): NREL/TP--520-25101; CONF-980735--PROC.; ON: DE98007497
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AMORPHOUS STATE
COATINGS
ELECTROCHROMISM
LIGHT TRANSMISSION
PHOTOCHROMIC MATERIALS
SILICON CARBIDES
SOLAR CELLS
WINDOWS