[25p-E206-1~9] 12.5 有機太陽電池

▲ [25p-E206-5] Revealing the low efficiency of tin perovskite solar cells with metal oxide/tin perovskite interface

〇(P)Ajay Kumar Baranwal¹、Shrikant Saini²、Tomohide Yabuki²、Qing Shen¹、Koji Miyazaki²、Shuzi Hayase¹ (1.Electro-Comm Univ.、2.Kyushu Inst Tech.)

キーワード：Tin halide perovskite, Poor rectification behaviour, Metal oxide/tin halide interface

Better optoelectronic properties of Lead-free tin halide perovskite (THP) have shown a ray of hope to compete toxic lead halide perovskite solar cells. Inorganic metal oxide medium is generally used to assist the perovskite crystal growth and easy charge collection in n-i-p structure solar cells. However, such lead-free THP coated on metal oxide layer generally show poor diode rectification behavior leading to poor solar cell efficiency. We have already reported, carrier density/electrical conductivity was enhanced when THP CsSnI₃ was coated on metal oxide Y₂O₃. The reason behind such enhanced carrier concentration was found to be formed Sn(II) vacancies or Sn(IV). This phenomenon of Sn(IV) formation with metal oxide Y₂O₃ is similar to poor rectification behaviour observed in n-i-p solar cells. This finding motivated us to check various metal oxides (Al₂O₃, SnO₂, TiO₂, NiOx, ZnO, ZrO₂) underneath layers with THP CsSnI₃ as atop layer. Interestingly, electrical conductivity values were varied. It can be estimated that underneath metal oxide layer can lead to easy Sn(II) to Sn(IV) oxidation. However, reason behind such Sn(II) to Sn(IV) oxidation which can lead to poor rectification behaviour is not yet clear.
In this work, we study the reason behind such Sn(IV) formation in metal oxide/tin perovskite interface, which significantly raises the carrier concentration and results in poor rectification characteristics. However, complementarily, Sn(IV) formation in THP films may help to harvest waste heat. Therefore, in this work, we also study the thermoelectric performance of THP films. The further details would be discussed at the conference.