Background
Polycrystalline Cd(Se)Te thin-film solar cells are made of a combination of cadmium (Cd), selenium (Se), and tellurium (Te) elements and exhibit efficient light absorption properties and a tunable bandgap depending on the ratio between the elements. Cd(Se)Te thin-film solar cells currently make up 5% of the global photovoltaic market, and are poised to gain additional market share if higher power conversion efficiencies can be achieved. The current industry goal is to reach greater than 26% efficiency, and the current record efficiency is 22.6%, indicating room for improvement.
There are two key limiting factors that are currently holding back Cd(Se)Te thin-film solar cells from reaching 26% efficiency. The first is the low dopability of p-type Cd(Se)Te, and the second is the low-lying valence band edge of Cd(Se)Te. These two issues combined make an ohmic hole contact very difficult.
Invention Description
Researchers at Arizona State University have developed a new approach to constructing Cd(Se)Te thin-film solar cells using a “remote junction” to help achieve 26% power conversion efficiency. This approach involves using an n-type Indium Tin Oxide (ITO) as a transparent hole selective layer integrated with a n-type absorber to form a p-n junction. This enables bifacial configuration and has the potential to reach 26% efficiency with low manufacturing costs.
Potential Applications:
- Thin-film solar cells with high power conversion efficiency
Benefits and Advantages:
- Low-cost – does not need to have acceptors inside the semiconductor absorber due to the “remote junction” concept
- Improved power conversion efficiency – potential to reach 26% efficiency
- High device stability – retains photovoltaic performance over time