CdTe

First Solar and its cadmium telluride (CdTe) technology dominate thin-film solar in the mainstream market. Valerie Thompson looks at the US-based business and the future of thin-film PV technology.

A new imaging system for contactless defect detection in roll-to-roll printed thin film solar cell manufacturing lines is available from InfinityPV, a Danish printed electronics equipment manufacturer. The so-called ultrafast laser beam induced current mapping system is suitable for manufacturers of perovskite, organic, kesterite, copper indicum gallium diselenide (CIGS) and amorphous silicon PV foils and can be retrofitted into existing roll-to-roll lines.

Researchers in the United Kingdom have tested the perfomance of cadmium telluride solar cells deployed on the AlSat-1N 3U CubeSat satellite from 2016 to 2022. Their findings show the devices exhibited no significant performance changes, nor any sign of delamination. 

Scientists in Bangladesh designed a cadmium telluride solar cell with upper/top and back contact materials made of aluminum (Al) and nickel (Ni). The device reportedly showed a quantum efficiency of around 100 % at visible wavelengths.

Practical matters, beyond simply improving on solar cell efficiency, have led the agenda at the European Photovoltaic Solar Energy Conference (EUPVSEC) going on this week in Lisbon. Policy and the geopolitics of solar manufacturing is the big question on everybody’s lips as the event passes its halfway point today. Concerns including grid integration, critical materials consumption, and public acceptance are all being aired frequently – illustrating a closer than ever link between work being done in the labs at solar energy institutes and the everyday lives and energy consumption of people in Europe and around the world.

Thin-film technologies have long promised to make a major impact on the solar industry but have largely been constrained to niche applications and research labs if they were not shredded by the market. After several false starts, current trade dynamics and promising research programs may help solar thin films find their place in the sun.

A US research team has developed a cadmium telluride (CdTe) solar cell through a lift-off method that reportedly ensures higher crystallinity of the cadmium sulfide film. The device has a power conversion efficiency of 12.60%, an open-circuit voltage of 0.829 V, a short-circuit current density of 23.64 mA/cm2, and a fill factor of 64.30%.

Scientists in the United States investigated adding a layer of copper-aluminum oxide to the rear side of a cadmium-telluride thin film cell, finding positive impacts on carrier lifetime and efficiency. With further work, the scientists say, the discovery could open up new routes to higher efficiencies in CdTe solar cells.

Scientists in the UK have explained the mechanism behind chlorine used to boost the efficiency of cadmium telluride thin-film solar cells. With new understanding of the chemical processes at work in the manufacturing process, the group hopes to be able to push for cell efficiencies beyond 25%.

The U.S.-based manufacturer is planning a vertically integrated thin-film solar module manufacturing facility in India. The factory will likely be built in Tamil Nadu and become operational in the second half of 2023.