@article{SchultzFenskeDionBertrandetal., author = {Schultz, Christof and Fenske, Markus and Dion-Bertrand, Laura-Isabelle and G{\´e}linas, Guillaume and Marcet, St{\´e}phane and Dagar, Janardan and Bartelt, Andreas and Schlatmann, Rutger and Unger, Eva and Stegemann, Bert}, title = {Hyperspectral Photoluminescence Imaging for Spatially Resolved Determination of Electrical Parameters of Laser-Patterned Perovskite Solar Cells}, series = {Solar RRL}, volume = {7}, journal = {Solar RRL}, number = {22}, publisher = {Wiley}, issn = {2367-198X}, doi = {10.1002/solr.202300538}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-18215}, abstract = {Absolute calibrated hyperspectral photoluminescence (PL) imaging is utilized to access, in a simple and fast way, the spatial distribution of relevant solar cell parameters such as quasi-Fermi level splitting, optical diode factor, Urbach energies Eu, and shunt resistances Rsh, without the need for electrical measurements. Since these metrics play a significant role in evaluating the process windows for electrical series interconnection by laser patterning, this approach is followed to systematically locate and quantify electrical losses that may occur as a result of the laser-patterning process for monolithic series interconnection. It is shown that both picosecond and nanosecond laser pulses can be used for successful series interconnection. In both cases, only minor lateral material alterations occur, localized in a few μm wide region adjacent to the edges of the scribe lines. Furthermore, the acquisition and analysis of these hyperspectral PL datasets provide insights in the material removal process, from which it is concluded that the perovskite is rather resilient against the thermal impact of the laser.}, subject = {Laserablation}, language = {en} } @article{FenskeSchultzDagaretal., author = {Fenske, Markus and Schultz, Christof and Dagar, Janardan and Kosasih, Felix Utama and Zeiser, Andreas and Junghans, Cornelia and Bartelt, Andreas and Ducati, Caterina and Schlatmann, Rutger and Unger, Eva and Stegemann, Bert}, title = {Improved Electrical Performance of Perovskite Photovoltaic Mini-Modules through Controlled PbI2 Formation Using Nanosecond Laser Pulses for P3 Patterning}, series = {Energy Technology}, volume = {9}, journal = {Energy Technology}, number = {4}, doi = {10.1002/ente.202000969}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-15841}, pages = {1 -- 8}, abstract = {The upscaling of perovskite solar cells to modules requires the patterning of the layer stack in individual cells that are monolithically interconnected in series. This interconnection scheme is composed of three lines, P1-P3, which are scribed using a pulsed laser beam. The P3 scribe is intended to isolate the back contact layer of neighboring cells, but is often affected by undesired effects such as back contact delamination, flaking, and poor electrical isolation. Herein, the influence of the laser pulse duration on the electrical and compositional properties of P3 scribe lines is investigated. The results show that both nanosecond and picosecond laser pulses are suitable for P3 patterning, with the nanosecond pulses leading to a higher open circuit voltage, a higher fill factor, and a higher power conversion efficiency. It is found that the longer pulse duration resultes in a larger amount of PbI2 formed within the P3 line and a thin Br-rich interfacial layer which both effectively passivate defects at the scribe line edges and block charge carrier in its vicinity. Thus, nanosecond laser pulses are preferable for P3 patterning as they promote the formation of beneficial chemical phases, resulting in an improved photovoltaic performance.}, subject = {Laserablation}, language = {en} } @article{SchultzFenskeOttoetal., author = {Schultz, Christof and Fenske, Markus and Otto, Nicolas and Dion-Bertrand, Laura-Isabelle and G{\´e}linas, Guillaume and Marcet, St{\´e}phane and Dagar, Janardan and Schlatmann, Rutger and Unger, Eva and Stegemann, Bert}, title = {Loss Analysis of P3 Laser Patterning of Perovskite Solar Cells via Hyperspectral Photoluminescence Imaging}, series = {Solar}, volume = {5}, journal = {Solar}, number = {2}, editor = {Boucl{\´e}, Johann}, publisher = {MDPI}, issn = {2673-9941}, doi = {10.3390/solar5020013}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-20545}, abstract = {Upscaling perovskite solar cells and modules requires precise laser patterning for series interconnection and spatial characterization of cell parameters to understand laser-material interactions and their impact on performance. This study investigates the use of nanosecond (ns) and picosecond (ps) laser pulses at varying fluences for the P3 patterning step of perovskite solar cells. Hyperspectral photoluminescence (PL) imaging was employed to map key parameters such as optical bandgap energy, Urbach energy, and shunt resistance. The mappings were correlated with electrical measurements, revealing that both ns and ps lasers can be utilized for effective series interconnections with minimal performance losses at optimized fluences. Our findings provide a deeper understanding of fluence-dependent effects in P3 patterning. Moreover, the results demonstrate that the process window is robust, allowing for reasonable cell performance even with deviations from optimal parameters. This robustness, coupled with the scalability of the laser patterning process, emphasize its suitability for industrial module production.}, subject = {Photoluminescence}, language = {en} }