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Solertix claims to have reduced performance losses in cell-to-module scaling by using an ultra-narrow 19.5 µm interconnect. It also claims that the proposed interconnect technique can be used to achieve 30% efficiency in paired area 4T tandem designs with a perovskite module on a silicon cell.
Italian perovskite specialist Solertix, a unit of Italian solar manufacturer FuturaSun, has manufactured mini perovskite solar panels with an active surface area of ??2.6 cm2 and a power conversion efficiency of 20.7%.
“We have optimized the laser processes to manufacture the interconnections that are used to go from the cells to the modules,” Solertix technology director Francesco Di Giacomo explained to pv magazine . “As the area used for interconnections does not produce energy, we have introduced a new design to minimize this area without introducing other types of losses. The factor that takes this into account is the geometric filling factor (GFF), which describes the relationship between the active area and the sum of the active area and the interconnections, and we have reached a record of around 99 .6%, while in literature it is difficult to go beyond 95%.”
In the research article “ Beyond 99.5% Geometrical Fill Factor in Perovskite Solar Minimodules with Advanced Laser Structuring ,” written in collaboration with scientists from the University of Rome Tor Vergata, of which Solertix is ??a spin-off, the Italian startup explains that, when moving from perovskite cells to modules, the losses may be due to the loss due to the lack of homogeneity of the layers, the loss ohmic of P2, the taps between P1 and P3 and the loss of resistance of the sheet.
The so-called layouts P1, P2 and P3 correspond to the three layout steps of the construction process of the monolithic interconnections that add tensions between the cells of the modules. Steps P1 and P3 aim to isolate the back contact layers from neighboring cells and step P2 creates an electrical path between the back contact of one cell with the front contact of an adjacent cell. The P3 step, in particular, is often the source of undesirable effects, such as back contact delamination, spalling, or poor electrical insulation, due to debris left in the trench.
The module was built with three cells, each with a surface area of ??0.87 cm2. All cells were designed with a glass and indium tin oxide substrate, a poly(triarylamine) (PTAA)-based hole transport material, a perovskite absorber, a methyl ester-based electron transport layer phenyl-C61-butyric (PCBM), a bathocuproin (BCP) buffer layer and a copper (Cu) metal contact.
“Two rectangular shapes have been designed with an active area of ??1 cm 2, with the aim of reducing the resistive losses that occur especially in the TCO electrode: the active areas are defined by a P3 scratch, followed by a P2 scratch. to use the remaining metal electrode as a current-collecting electrode for the TCO,” explain the researchers, who point out that the use of the P2-P3 process made it possible to integrate a current-collecting grid using the same metal layer as the upper electrodes.
The group tested a module built with this architecture and an ultralight 19.5 µm interconnect under standard lighting conditions and found that it can achieve an efficiency of 20.7%, a fill factor of 81.7%, and a fill factor geometric of 96%, without detecting relevant resistive losses.
Looking ahead, the team says it wants to apply an unspecified advanced alignment procedure to avoid possible deformation of the module during processing. “By applying this novel approach to the semi-transparent modules manufactured at Solertix, we are close to reaching an efficiency of 30% using a 4T tandem of coincident area with a perovskite module on a silicon cell,” said Di Giacomo, without giving further details.
Solartix was acquired by FuturaSun in June 2023. It was created at the Organic Solar Center (CHOSE), created by Professor Aldo Di Carlo, who also assumed the position of president of the scientific committee of the Italian startup.
In March 2021, the University of Rome Tor Vergata presented a perovskite solar module with a total active area of ??42.8 cm2 and an aperture area of ??50 cm2. The panel was built with 20% efficient perovskite cells connected in 14 arrays and was able to retain 90% of the initial efficiency after 800 h of thermal stress at 85 degrees Celsius.
A few months later, it presented a perovskite solar module with cells based on the triple cation cesium methylammonium formamidinium (CsMAFA). |
