Fig. 6: 3D device simulations for CZTSe solar cells.
From: Unveiling microscopic carrier loss mechanisms in 12% efficient Cu2ZnSnSe4 solar cells
a, The simulated contour of FF versus electron and hole mobilities under fixed electron and hole lifetime of 15 ns and 0.3 ns, respectively, which are obtained from fitting J–V and EQE curves. The simulated JSC and VOC under the same conditions are shown in Supplementary Fig. 26. b, Simulated VOC (light yellow), FF (light purple) and JSC (light blue) versus electron and hole lifetimes within ±1% deviation compared with the experimental baseline. The full contours are shown in Supplementary Fig. 27. The overlapped region coloured in dark brown indicates where the electron and hole lifetime can well fit experimental VOC, FF and JSC simultaneously. The other overlapped regions indicate where VOC and JSC (green), JSC and FF (dark blue) and VOC and FF (military green) are well fitted. c,d, Simulated contours of efficiency against carrier lifetime and grain boundary recombination velocity under hole density of 2 × 1015 cm−3 (c) and 5 × 1016 cm−3 (d), respectively. The red star in c indicates the current state-of-the-art CZTSe cells. The optical loss is reduced in d to an extent that maximum JSC can achieve 40 mA cm−2. The efficiency contours under hole density of between 5 × 1015 cm−3 and 2 × 1016 cm−3 are shown in Supplementary Fig. 28.
