Material Properties Flashcards
7 cards from real SE ENGR. practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Material Properties flashcards as text
What is the approximate bandgap of crystalline silicon at room temperature?
Answer: 1.12 eV
Crystalline silicon has an indirect bandgap of about 1.12 eV at 300 K.
Why is cadmium telluride (CdTe) well suited to thin-film PV absorbers?
Answer: Its direct bandgap near 1.45 eV gives strong absorption in a few microns
CdTe's direct bandgap of about 1.45 eV closely matches the solar spectrum and absorbs strongly in thin layers.
Low-iron glass is used for PV module front sheets mainly because it:
Answer: Reduces absorption losses and raises solar transmittance
Iron oxide absorbs light, so low-iron glass transmits about 91% or more of solar radiation.
As a crystalline silicon cell's temperature rises, which parameter drops the most?
Answer: Open-circuit voltage
Voc falls by roughly 0.3%/°C, which drives most of the power loss, while Isc rises slightly.
What is the main function of EVA in a crystalline PV module?
Answer: Encapsulating and bonding cells while giving optical coupling and protection
Ethylene vinyl acetate is cross-linked during lamination to bond, cushion and optically couple the cells to the glass.
Which encapsulant is often chosen over EVA to resist potential-induced degradation (PID)?
Answer: Polyolefin elastomer (POE)
POE has higher volume resistivity and lower water vapor transmission than EVA, which reduces PID and acetic acid corrosion.
Which material is commonly used as a transparent conductive oxide in thin-film modules?
Answer: Fluorine-doped tin oxide (FTO)
FTO and ITO combine high visible transmittance with good electrical conductivity for front contacts.