讲座题目：Highly-Efficient Perovskite Light-Emitting Diodes Enabled by SynergeticDevice Architecture
Prof. Jianxin Tang received his B.Sc. degree in physics from Zhejiang University in 2002,and Ph.D. degree in Physics and Materials Science from City University of HongKong in 2006. In 2008, he was appointed professor at the Institute of NanoFunctional & Soft Materials (FUNSOM), Soochow University. His currentresearch areas/interests span device physics and surface science on organic andperovskite light-emitting diodes technology for flat panel display andsolid-state lighting, and organic/perovskite photovoltaic cells for renewableenergy, including localized electronic state and charge barrier formation atorganic interfaces, and novel device architectures to improve deviceperformance with interface modification for carrier transport and lightmanipulation.
The development of solution-processed inorganicmetal halide perovskite light-emitting diodes (PeLEDs) is currently hindered bylow emission efficiency due to morphological defects and severe non-radiativerecombination in all-inorganic perovskite emitters, as well as the lighttrapping by substrate and waveguide modes. In this talk, we will introduce ourrecent progress on bright PeLEDs, where were obtained by synergetic morphologycontrol over cesium lead bromide (CsPbBr3) perovskite films with thecombination of two additives. The phenethylammonium bromide (PEABr) additiveenables the formation of mixed-dimensional CsPbBr3 perovskitesfeaturing the reduced grain size (<15 nm) and efficient energy funneling,while the dielectric polyethyleneglycol (PEG) additive promotes the formationof highly compact and pinhole-free perovskite films with defect passivation atgrain boundaries. Consequently, green PeLEDs achieve a current efficiency (CE)of 37.14 cd/A and an external quantum efficiency (EQE) of13.14% with the maximum brightness up to 45990 cd/m2 and high colorpurity. Furthermore, we propose a facile route by adopting the light-extractionnanostructures at the front electrode/perovskite interface to enhance theoutcoupling efficiency of waveguided light in PeLEDs. As a result, themaximum EQE and CE of CsPbBr3 PeLEDs are improved to 20.3% and 61.9cd/A, while retaining spectral and angular independence. Further reducing lightloss in the substrate mode, we have achieved the efficiencies of 28.2% and 88.7cd/A, which represent the highest values reported to date for PeLEDs. These results represent asubstantive step towards achieving practicalapplications of PeLEDs.