Copper-based Perovskites with Horizontal Transition Dipole Moment for Highly Efficient Light-emitting Diodes

卤化物钙钛矿以其非凡的光电特性，如高颜色纯度，易于溶液加工，近100%的光致发光量子产率（PLQY）和广泛的光发射可调性，准备彻底改变led显示技术。然而，要实现钙钛矿led在显示和照明技术中的实际应用，必须解决一些关键问题，如大多数钙钛矿中存在有毒的铅，以及典型钙钛矿led的稳定性弱。铜基钙钛矿，特别是蓝色发光的Cs3Cu2I5，由于其低毒性、显著的PLQY和优异的稳定性，是最有前途的无铅钙钛矿家族之一。然而，Cs3Cu2I5蓝色led的记录外量子效率（EQE）仅为1.12%。在本提案中，我们将通过控制发射层的跃迁偶极矩取向来提高铜基钙钛矿led的光解耦效率。通过合成超薄纳米板并将其组装成薄膜，制备了具有水平过渡偶极矩为主的铜基钙钛矿薄膜。以这些薄膜为发射层的铜基钙钛矿led将被制造出来，并用时域有限差分（FDTD）方法进行理论研究。通过这样做，我们的目标是打破铜基钙钛矿led的EQE记录，蓝色led的EQE超过10%，白色led的EQE超过4%。

Halide perovskites are poised to revolutionize the LEDs display technology for their extraordinary optoelectronic properties, such ashigh colour purity, easy solution processibility, nearly 100% photoluminescence quantum yield (PLQY), and broad light emissiontunability. However, to realize the practical applications of perovskite LEDs in display and lighting technology, some key issues, suchas the presence of toxic lead in most emissive perovskites and the weak stability of typical perovskite LEDs, must be solved. Copper-basedperovskites, especially the blue emissive Cs3Cu2I5, are one of the most promising lead-free perovskite families for their lowtoxicity, remarkable PLQY, and excellent stability. Nevertheless, the record external quantum efficiency (EQE) of Cs3Cu2I5 blue LEDs isonly 1.12%. In this proposal, we will improve the light outcoupling efficiency of copper-based perovskite LEDs by controlling thetransition dipole moment orientation of the emissive layers. Copper-based perovskite thin films with dominated horizontal transitiondipole moments will be fabricated by synthesizing their ultrathin nanoplates and assembling these nanoplates into thin films.Copper-based perovskite LEDs with these thin films as emissive layers will be manufactured and theoretically investigated with thefinite-difference time-domain (FDTD) method. By doing so, we aim to break the record for the EQE of copper-based perovskite LEDswith an EQE surpassing 10% in blue LEDs and surpassing 4% in white LEDs.