Zou Wei, Li Renzhi, Zhang Shuting, Liu Yunlong, Wang Nana, Cao Yu, Miao Yanfeng, Xu Mengmeng, Guo Qiang, Di Dawei, Zhang Li, Yi Chang, Gao Feng, Friend Richard H, Wang Jianpu, Huang Wei
Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, 211816, Nanjing, China.
School of Physical Science and Information Technology, Liaocheng University, Liaocheng, 252059, Shandong, China.
Nat Commun. 2018 Feb 9;9(1):608. doi: 10.1038/s41467-018-03049-7.
Efficiency roll-off is a major issue for most types of light-emitting diodes (LEDs), and its origins remain controversial. Here we present investigations of the efficiency roll-off in perovskite LEDs based on two-dimensional layered perovskites. By simultaneously measuring electroluminescence and photoluminescence on a working device, supported by transient photoluminescence decay measurements, we conclude that the efficiency roll-off in perovskite LEDs is mainly due to luminescence quenching which is likely caused by non-radiative Auger recombination. This detrimental effect can be suppressed by increasing the width of quantum wells, which can be easily realized in the layered perovskites by tuning the ratio of large and small organic cations in the precursor solution. This approach leads to the realization of a perovskite LED with a record external quantum efficiency of 12.7%, and the efficiency remains to be high, at approximately 10%, under a high current density of 500 mA cm.
效率滚降是大多数类型发光二极管（LED）的一个主要问题，其起源仍存在争议。在此，我们展示了基于二维层状钙钛矿的钙钛矿LED中效率滚降的研究。通过在工作器件上同时测量电致发光和光致发光，并辅以瞬态光致发光衰减测量，我们得出结论，钙钛矿LED中的效率滚降主要是由于发光猝灭，这可能是由非辐射俄歇复合引起的。通过增加量子阱的宽度可以抑制这种有害影响，通过调节前驱体溶液中大小有机阳离子的比例，这在层状钙钛矿中很容易实现。这种方法实现了一种钙钛矿LED，其外部量子效率达到创纪录的12.7%，并且在500 mA cm的高电流密度下，效率仍保持在约10%的较高水平。
