Shang Yuequn, Liao Yuan, Wei Qi, Wang Ziyu, Xiang Bo, Ke Youqi, Liu Weimin, Ning Zhijun
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
Sci Adv. 2019 Aug 16;5(8):eaaw8072. doi: 10.1126/sciadv.aaw8072. eCollection 2019 Aug.
Organic-inorganic hybrid halide perovskites are emerging as promising materials for next-generation light-emitting diodes (LEDs). However, the poor stability of these materials has been the main obstacle challenging their application. Here, we performed first-principles calculations, revealing that the molecule dissociation energy of Dion-Jacobson (DJ) structure using 1,4-bis(aminomethyl)benzene molecules as bridging ligands is two times higher than the typical Ruddlesden-Popper (RP) structure based on phenylethylammonium ligands. Accordingly, LEDs based on the DJ structure show a half-lifetime over 100 hours, which is almost two orders of magnitude longer compared with those based on RP structural quasi-two-dimensional perovskite. To the best of our knowledge, this is the longest lifetime reported for all organic-inorganic hybrid perovskites operating at the current density, giving the highest external quantum efficiency (EQE) value. In situ tracking of the film composition in operation indicates that the DJ structure was maintained well after continuous operation under an electric field.
有机-无机杂化卤化物钙钛矿正成为下一代发光二极管（LED）的有前途的材料。然而，这些材料的稳定性差一直是挑战其应用的主要障碍。在这里，我们进行了第一性原理计算，结果表明，使用1,4-双（氨甲基）苯分子作为桥连配体的狄翁-雅各布森（DJ）结构的分子解离能比基于苯乙铵配体的典型鲁德尔斯登-波珀（RP）结构高出两倍。因此，基于DJ结构的LED显示出超过100小时的半衰期，与基于RP结构的准二维钙钛矿的LED相比，几乎长了两个数量级。据我们所知，这是在当前电流密度下运行的所有有机-无机杂化钙钛矿中报道的最长寿命，具有最高的外量子效率（EQE）值。运行过程中对薄膜成分的原位跟踪表明，在电场下连续运行后，DJ结构保持良好。
