Numerical simulation design of all-inorganic hole-transport-layer-free CsSnI3 (Sn-rich)/CsSnI3 perovskite efficient solar cells

As perovskite solar cell (PSC) technology is about to be commercialized, the use of toxic and organic material is still a problem. At the same time, hole-transport-layer-free (HTL-free) PSCs have received widespread attention given their simple structure and low manufacturing cost. In this study, we use the wxAMPS software to produce a simulation, using CsSnI3(Sn-rich)/CsSnI3 all-perovskite as the absorption layer and carbon as the back electrode, as well as to propose a new, to the best of our knowledge, inorganic HTL-free PSC. CsSnI3 is a narrowband material whose absorption range can be extended to the near-infrared spectral region; it also has very high hole mobility and so can be used as both the light absorption layer and the HTL. Compared with that of standard structure devices, the photoelectric conversion efficiency (PCE) of the PSC is better. When the perovskite layer thickness is 900 nm, the optimal PCE is 14.91%, the open-circuit voltage is 0.81 V, the short-circuit current is 23.77mA/cm2, and the fill factor is 77.37%. Our research further found that CsSnI3 (Sn-rich) has the best PCE at 1018∼1019/cm3. When the electron transport layer and the light absorption layer conduction band offset is −0.2eV, the PCE has an optimal value of 15.02%. Finally, by changing the light temperature, the PCE value of our study is between 12.07% and 16.61% under non-extreme work environments, and the results show that the device has good thermostability. This proves that the proposed all-inorganic HTL-free PSCs have broad prospects in future photovoltaic and optoelectronics applications and provide theoretical guidance for the manufacture of non-toxic and inorganic PSCs.