Perovskite Silicon Tandem Solar Cells Above 30 Conversion Efficiency on Submicron Sized Textured Czochralski Silicon Bottom Cells with Improved Hole Transport Layers
In perovskite silicon tandem solar cells, the utilization of silicon heterojunction SHJ solar cells as bottom cells is one of the most promising concepts. Here, we present optimization strategies for the top cell processing and their integration into SHJ bottom cells based on industrial Czochralski Cz Si wafers of 140 amp; 956;m thickness. We show that combining the self assembled monolayer [4 3,6 dimethyl 9H carbazol 9 yl butyl]phosphonic acid Me 4PACz with an additional phosphonic acid PA with different functional groups, can improve film formation when used as a hole transport layer improving wettability, minimizing shunt fraction and reducing nonradiative losses at the buried interface. Transient surface photovoltage and transient photoluminescence measurements confirm that the combined Me 4PACz PA layer has similar charge transport properties to Me 4PACz alone. Moreover, this work demonstrates the potential for thin, double side submicron sized textured industry relevant silicon bottom cells yielding a high accumulated short circuit current density of 40.2 mA cm2 and reaching a stabilized power conversion efficiency of gt;30 . This work paves the way toward industry compatible, highly efficient tandem cells based on a production compatible SHJ bottom cel
