Materials chemistry

Semiconductors, perovskites

Connect band structure and charge-carrier populations to semiconductor behavior, then examine why halide perovskites are promising yet challenging optoelectronic materials.

1 Lower secondary 2 Upper secondary 3 Undergraduate 4 Advanced 5 Research

IntuitionFrom insulator to conductor

Explore the ideal ABX₃ framework: A-site cations occupy cavities, B cations sit in BX₆ octahedra, and X anions connect the octahedra.

SchoolBands and charge carriers

Definition: Band gap

Example

Solution

σ ≈ qnμn = (1.602×10⁻¹⁹)(2.0×10²¹)(0.10) ≈ 32 S m⁻¹.

Typical roles of perovskite constituents
Site	Typical role
A	Cavity-filling cation; tunes structure and stability
B	Octahedral cation; contributes strongly to band-edge states
X	Anion linking BX₆ octahedra

UndergraduateQuantitative optoelectronic picture

References

The emergence of perovskite solar cells · H. J. Snaith, 2013