Lee Seungjae, Kim Junho, Kim Hyojun, Kim Changwon, Kim Siin, Kim Changjo, Lee Heeseung, Choi Bongjun, Muthu Chinnadurai, Kim Taehyun, Lee Jihyung, Lee Seungbok, Ihee Hyotcherl, Lee Jung-Yong
School of Electrical Engineering (EE), Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
Sci Adv. 2024 May 17;10(20):eadn8465. doi: 10.1126/sciadv.adn8465.
Deep-blue perovskite light-emitting diodes (PeLEDs) of high purity are highly sought after for next-generation displays complying with the Rec. 2020 standard. However, mixed-halide perovskite materials designed for deep-blue emitters are prone to halide vacancies, which readily occur because of the low formation energy of chloride vacancies. This degrades bandgap instability and performance. Here, we propose a chloride vacancy-targeting passivation strategy using sulfonate ligands with different chain lengths. The sulfonate groups have a strong affinity for lead(II) ions, effectively neutralizing vacancies. Our strategy successfully suppressed phase segregation, yielding color-stable deep-blue PeLEDs with an emission peak at 461 nanometers and a maximum luminance () of 2707 candela per square meter with external quantum efficiency (EQE) of 3.05%, one of the highest for Rec. 2020 standard-compliant deep-blue PeLEDs. We also observed a notable increase in EQE up to 5.68% at of 1978 candela per square meter with an emission peak at 461 nanometers by changing the carbon chain length.
高纯度的深蓝色钙钛矿发光二极管（PeLED）对于符合Rec. 2020标准的下一代显示器来说备受追捧。然而，为深蓝色发光体设计的混合卤化物钙钛矿材料容易出现卤化物空位，由于氯空位的形成能较低，这种空位很容易出现。这会降低带隙稳定性和性能。在此，我们提出一种使用不同链长的磺酸盐配体的针对氯空位的钝化策略。磺酸根基团对铅（II）离子具有很强的亲和力，能有效中和空位。我们的策略成功抑制了相分离，得到了颜色稳定的深蓝色PeLED，其发射峰位于461纳米，最大亮度（）为每平方米2707坎德拉，外量子效率（EQE）为3.05%，是符合Rec. 2020标准的深蓝色PeLED中最高的之一。通过改变碳链长度，我们还观察到在每平方米1978坎德拉、发射峰位于461纳米时，EQE显著提高至5.
