[20p-C101-1~17] 16.3 Bulk, thin-film and other silicon-based solar cells

▲ [20p-C101-9] A Nanocrystalline Silicon Recombination Junction Layer for Perovskite-Silicon Tandem Solar Cells

〇(P)Calum McDonald¹, Hitoshi Sai¹, Vladimir Svrcek¹, Atsushi Kogo¹, Tetsuhiko Miyadera¹, Takurou N. Murakami¹, Masayuki Chikamatsu¹, Yuji Yoshida¹, Takuya Matsui¹ (1.AIST)

Keywords:silicon, perovskite, tandem

We have previously reported a perovskite-silicon tandem solar cell using an n-type hydrogenated nanocrystalline silicon (nc-Si:H) recombination junction (RJ) layer that can be deposited in situ onto the silicon subcell and provide superior device performance to the common ITO RJ layer.[1] Here, we studied the thickness dependency of (n) nc-Si:H on the device performance and find that the optimum thickness of the (n) nc-Si:H RJ layer is ~20-30 nm, which is the minimum thickness required to achieve a full coverage of Si nanocrystallites on its surface, leading to low contact resistance with an overlying SnO₂ electron transport layer of the perovskite top cell. Furthermore, the (n) nc-Si:H RJ layer also functions as a refractive index matching layer in tandem solar cells because of its surface roughening nature when the thickness is greater than 20 nm. As a result, we attain a current-matched tandem solar cell exhibiting a PCE of 21.4% with V_OC of >1.8 V using a 20-nm thick (n) nc-Si:H layer. Further efficiency improvement is expected by reducing the large optical reflection loss. These findings provide an insight into the realization of highly efficient and industrially feasible tandem solar cells.
[1] C. McDonald et al., JSAP fall meeting 2021, 10a-N104-9.