27.9 Efficient Monolithic Perovskite Silicon Tandem Solar Cells on Industry Compatible Bottom Cells

Abstract

Monolithic perovskite silicon tandem solar cells recently surpass the efficiency of silicon single junction solar cells. Most tandem cells utilize gt;250 amp; 8201; amp; 956;m thick, planarized float zone FZ silicon, which is not compatible with commercial production using lt;200 amp; 8201; amp; 956;m thick Czochralski CZ silicon. The perovskite silicon tandem cells based on industrially relevant 100 amp; 8201; amp; 956;m thick CZ silicon without mechanical planarization are demonstrated. The best power conversion efficiency PCE of 27.9 is only marginally below the 28.2 reference value obtained on the commonly used front side polished FZ Si, which are about three times thicker. With both wafer types showing the same median PCE of 27.8 , the thin CZ Si based devices are preferred for economic reasons. To investigate perspectives for improved current matching and, therefore, further efficiency improvement, optical simulations with planar and textured silicon have been conducted the perovskite s bandgap needs to be increased by amp; 8776;0.02 amp; 8201;eV when reducing the silicon thickness from 280 to 100 amp; 8201; amp; 956;m. The need for bandgap enlargement has a strong impact on future tandem developments ensuring photostable compositions with lossless interfaces at bandgaps around or above 1.7 amp; 8201;e