Imec, a Belgian international research and development and innovation organization that has been active in the field of nano and digital technology, announced the use of cross-back contact (IBC) technology on perovskite/silicon tandem cells to achieve a conversion efficiency of 27.1%. Other companies and research institutes are similar, Imec said, by carefully designing its perovskite materials, the efficiency can reach more than 30%. This further proves the application prospect of the technology to reduce the cost of existing photovoltaic technology.
The tandem cell achieving 27.1% conversion efficiency comprises a 0. 13 cm 2 perovskite layer stacked on top of a 4 cm 2 silicon IBC cell. When the perovskite layer extends over the entire 4 cm square, the researchers recorded a battery efficiency of 25. 3%, they pointed out that this is still an improvement in the efficiency of 23% efficiency of silicon cells alone. 'The main impact is caused by the interconnect loss of small cells from small cells to serial interconnect cells in 4cm2 modules.' Imec Thin Film PV R&D Manager Tom Aernouts explained. 'There is a small series resistance loss in the transparent electrode, but mainly for some area loss between the interconnected cells. We are working hard to further reduce these losses.'
The researchers also pointed out that if carefully designed, the translucent perovskite layer can minimize the heat loss in the silicon cell. The team also pointed out that band gap adjustment is a key development to achieve this level of efficiency. 'We have been in the past two years I've been researching this tandem technology,” Imec researcher Manoj Jaysankar explains. 'The biggest difference from previous versions is the engineering and processing of perovskite absorbers, adjusting their band gaps to optimize the efficiency of the silicon series configuration.'
Although the stability of perovskite materials under non-laboratory conditions has been a major obstacle to their ability to achieve quantitative production, Imec and other research groups have indicated that much progress has been made in this area. 'Long-term stability limits The device is indeed a perovskite cell or component,' Aernouts explained. 'The inherent stability of the perovskite material used here is sufficient for thermal testing at 85 °C for more than 1000 hours, which is a typical IEC standard test condition. So far, we have not observed any negative impact on stability from individual cells to interconnected cells in the component configuration. Further stability testing of perovskites is underway and is usually in the promotion of perovskites Good progress has been made in the stability of PV devices.'
The team from Imec will now focus on driving more than 30% of its tandem batteries and invite companies throughout the supply chain to collaborate with them. Aernouts said that this efficiency-enhancing approach will focus on fine-tuning materials and using new configurations: In this 4T configuration, further improvements can be obtained by finer adjustment of the transparency of the electrode to reduce loss and range efficiency by 30% ', 'We will also study the 2T configuration, where the optical boundary conditions of the middle electrode are indeed less stringent , allowing for better optical coupling. '
Imec's latest efficiency record is close to the British/German perovskite expert Oxford PV, which has an efficiency of 27.3% on a 1cm2 series battery.
