While silicon has dominated solar power for years, thin-film photovoltaic technologies offer a compelling alternative. Two of the better-known thin films are Cadmium Telluride (CdTe) and Copper Indium Gallium Selenide (CIGS).
What thin-film is
In place of thick silicon wafers, CdTe and CIGS use layers of semiconductor material just a few micrometres thick, deposited onto a glass or flexible substrate. Because the active layer is so thin, less material is needed and the fabrication process can be very different from crystalline silicon.
CdTe (Cadmium Telluride)
CdTe panels are manufactured largely in large glass-on-glass modules. They have become a mainstream option in utility-scale solar because:
- The manufacturing process can be very energy efficient
- Production costs are lower than many silicon modules
- Modules exhibit good performance in diffuse light and high temperatures
Long-established producers like First Solar have demonstrated multi-decade field durability
CIGS (Copper Indium Gallium Selenide)
CIGS offers similar advantages but on a different material system:
- Flexible or lightweight modules are possible
- Good spectral response (captures a broad range of sunlight wavelengths)
- Excellent performance in diffuse and low-light conditions
CIGS can be used in specialised applications e.g,, on curved surfaces, building-integrated photovoltaics, or portable power systems.
Performance characteristics
- Typical module efficiencies range from 18% to 22%, depending on quality and processing
- Temperature coefficients are competitive with silicon
- Thin films often perform well in hot conditions and diffuse/cloudy light
Strengths
- Lower material use compared with crystalline silicon
- Excellent diffuse-light performance i.e. for cloudy or northern skies
- Proven durability in utility installations (especially CdTe)
- Potential for flexible or lightweight modules (CIGS)
Trade-offs
- Lower peak efficiencies than the best silicon technologies
- CdTe uses cadmium (a toxic heavy metal) requiring careful recycling and handling
- CIGS production consistency varies by manufacturer
Where thin-film shines
CdTe and CIGS excel in large solar farms where land cost is low and diffuse light is common, or where flexibility and light weight are valuable (such as on curved roofs or in transportable systems). In northern climates, their strong performance in diffuse light and milder temperature response helps narrow the gap with premium silicon options.
Boˆreal 