[11a-S221-1~12] 12.5 Organic solar cells

▲ [11a-S221-7] 【Highlight】Reduced strain by cesium addition leading to the improvement in the efficiency of tin-lead mixed perovskite solar cells

〇(PC)Gaurav Kapil^1,2, Takeru Bessho¹, Chi Huey Ng², Kengo Hamada², Takumi Kinoshita¹, Qing Shen³, Taro Toyoda³, Takurou N. Murakami⁴, Hiroshi Segawa¹, Shuzi Hayase² (1.The Univ. of Tokyo, 2.Kyu. Inst. of Tech., 3.Uni. of Elec. Comm., 4.AIST)

Keywords:Perovskite solar cell, tin-lead, high efficiency

Tin-lead (Sn-Pb) perovskite solar cells (PSCs) can attain higher power conversion efficiency (PCE) than pure Pb based PSCs, owing to their ideal band gap (1.2 eV-1.4 eV) according to the Shockley-Queisser (SQ) limit [1,2]. However, being a low band gap material and prone to oxidation of Sn²⁺ to Sn⁴⁺, Sn-Pb solar cells suffer from voltage loss (V_L). To decrease the V_L, we have already introduced a spike like structure which led to a PCE of 17.6% [3]. To further decrease V_L, in this work we demonstrate that Cesium ion (Cs⁺) incorporation into the lattice of Sn-Pb absorbers can relax the strained lattice. As a result, open circuit voltage (Voc) more than 0.8 V and PCE more than 20% was obtained.
References
1. D. Zhao & Y. Yan et al, Nat. Energy., 2017, 2, 1-7.
2. W. Shockley, H. J. Queisser, J. Appl. Phys. 1961, 32, 510.
3. G. Kapil and S. Hayase et al., Nanoletters, 2018, 18, 3600-3607.