Fig. 4: Improvement of SHJ solar cells by light-induced dark conductivity increase and boron doping activation.
a, Device structure. b, FF evolution of as-prepared and annealed devices as a function of light soaking time under 1 sun illumination. Standard cell and 180 °C devices are as-prepared and annealed for 2 h at 180 °C, respectively. The FF evolution of 13 A devices is also shown. c, The FF evolution under different light intensities. Error bars on mean values are standard deviations from 20 devices. d,e, FF (d) and PCE (e) of 316 SHJ solar cells before (Ref.) and after (LS) 70 s of light soaking under 60 sun illumination. f, Current–voltage curves of SHJ solar cells tested by National Photovoltaic Industry Metrology and Testing Center (NPVM) and ISFH CalTeC (see Supplementary Data 1 for details). The ISFH results are tested in different modes, that is, one uses the total area (244.81 cm2) whereas the other uses an aperture mask shadowing the cell edges. g, Comparison of PCEs with the best c-Si solar cells in the solar cell efficiency tables34 and references therein. The total- and designated-area labels indicate testing using the total area and an aperture mask respectively. IBC indicates that electrodes are interdigitated-back-contacted. h, 1,000 h DH85 degradations of FF and PCE of six inch devices. The initial FF and PCE are 82.31% and 23.34%, respectively. i, 3,000 h DH85 degradations of FF and power of a module. The initial FF and power are 80.2% and 331.1 W, respectively. j, Degradations of FF and power of a module during 600 thermal cycles between −40 °C and 85 °C. The initial FF and power are 79.5% and 331.0 W, respectively. The curves in c and h–j are guides to the eye, whereas the curves in d and e are fitted by normal distributions. All tests are conducted under 100 mW cm−2 at 25 °C.
