Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Korea.
Science. 2020 Oct 2;370(6512):108-112. doi: 10.1126/science.abc4417.
High-efficiency lead halide perovskite solar cells (PSCs) have been fabricated with α-phase formamidinium lead iodide (FAPbI) stabilized with multiple cations. The alloyed cations greatly affect the bandgap, carrier dynamics, and stability, as well as lattice strain that creates unwanted carrier trap sites. We substituted cesium (Cs) and methylenediammonium (MDA) cations in FA sites of FAPbI and found that 0.03 mol fraction of both MDA and Cs cations lowered lattice strain, which increased carrier lifetime and reduced Urbach energy and defect concentration. The best-performing PSC exhibited power conversion efficiency >25% under 100 milliwatt per square centimeter AM 1.5G illumination (24.4% certified efficiency). Unencapsulated devices maintained >80% of their initial efficiency after 1300 hours in the dark at 85°C.
高效卤化铅钙钛矿太阳能电池（PSCs）已采用α 相甲脒碘化铅（FAPbI）和多种阳离子稳定化制成。合金化阳离子极大地影响了带隙、载流子动力学和稳定性，以及晶格应变，从而产生了不需要的载流子陷阱。我们在 FAPbI 的 FA 位取代铯（Cs）和甲脒二铵（MDA）阳离子，并发现 FA 位的 0.03 摩尔分数 MDA 和 Cs 阳离子降低了晶格应变，从而提高了载流子寿命，并降低了 Urbach 能量和缺陷浓度。在 100 毫瓦每平方厘米 AM 1.5G 光照下（24.4%的认证效率），性能最佳的 PSC 的功率转换效率超过 25%。未封装的器件在 85°C 黑暗中 1300 小时后仍保持初始效率的 80%以上。
