Last week, the research teams of Professor Wang Xuehua and Professor Liu Jin from the School of Physics, Sun Yat-sen University proposed, designed and fabricated an integrated quantum light source structure with a single quantum dot embedded in an angular grating micro-ring resonator, and realized the brightest chip-type single-photon source triggering orbital angular momentum in the world. The research results were published in Nature Nanotechnology (doi:10.1038/S 41565). Recently, Professor Li Juntao from the School of Physics of Sun Yat-sen University, in collaboration with Kylie R. Catchpole and Thomas P. White from the Australian National University, published an important research result in Science magazine. This paper will introduce this achievement next.

First author: Jun Peng.

Reporter: Li Juntao, Kelly R. Ketchupol, Thomas P. White.

Australian National University, Sun Yat-sen University.

Doi:10.1126/science. abb8687

At present, efficient private security companies face two major challenges:

1. Reduce interfacial recombination, maximize Voc and FF, and do not hinder charge extraction.

2. Maintain high efficiency, especially high FF, in a larger PSCs area.

1. The author proposes a new electron transport layer (ETL), which replaces the commonly used mesoporous TiO 2(meso-TiO 2) electron transport layer with nano-patterned TiO 2 nanorod array.

2. Ultra-thin polymer passivation layer can effectively passivate and generate nano-scale patterned ETL- perovskite interface, thus achieving high Voc, low series resistance and high FF while maintaining excellent charge extraction and interface transmission performance.

3. The certified power conversion efficiency (PCE) is as high as 2 1.6%, and the FF is as high as 0.839 on the large area PSCs of 1 cm2. Under the conditions of Voc= 1.240 V and FF=0.845, the PCE of a small area PSCs of about 0. 1.65 cm2 can reach about 23. 1.7%.

4. This work proves the important interaction among ETL morphology, interface passivation and charge transport at ETL- perovskite interface.

Figure 1. Certified performance of recorded PSC

Figure 2. Statistical distribution of TiO2 ETL with nanostructure and controllable PSCs photovoltaic parameters for nano-patterning.

Key points:

1. By combining nano-patterned ETL with dopant-free mixed hole transport layer (HTL), this structure can change the spatial distribution of passivation layer through passivation interface, thus providing effective passivation and excellent charge extraction. A large area PSCs of 65438±0 cm2 was prepared and obtained, and its certified PCE reached 265438 0.6% and FF reached 0.839.

2. This nano-scale patterned structure can be compatible with commercial scale manufacturing using nano-imprint technology, and some form of self-assembled ETL nanostructures can also provide an irregular surface sufficient to form local contacts through the passivation layer.

Figure 3. Theoretical simulation results

Key points:

1. The author studies and explains the interface properties of nanostructures by using three-dimensional (3D) numerical simulation, and accurately reproduces the experimental trend of nano-scale geometric patterns enhanced and observed by FF.

2. Simulation and experimental analysis show that this nano-interface sets a reasonable limit for the area fraction of nanorods exposed on the ETL- perovskite interface and the density of composite active defects.

3. The TiO _ 2 nanorods are not completely covered by PMMA:PCBM (polymethyl methacrylate: phenyl -c 665438+ methyl butyrate), and the locally exposed low-resistance contact area is directly similar to the local contact structure in high-efficiency silicon solar cells.

Figure 4. Device performance and long-term stability test of 1cm2 perovskite battery.

Key points:

1. The authors found that the ion-free mixed hole transport layer (HTL) provided similar battery performance as the doped substitute.

2. After being exposed to 85% and 85% relative humidity 1000 hours, the packaged battery containing the new combination of ETL and HTL still maintains the initial efficiency of >: 90%.

Original link:

https://science.sciencemag.org/content/37 1/6527/390

Li Juntao

Li Juntao, currently a professor at the School of Physics, Sun Yat-sen University, is mainly engaged in the study of light field regulation in semiconductor flat micro-nano structures by using electron beam direct writing equipment. Research interests: Nanoletters (20 18), Laser &; Photonics review (20 18), ACS photonics (20 17)ESI) Quasi-random light trapping micro-nano structure for ultra-thin solar cells (Nature Communications (2013)) Near infrared silicon-based laser (laser &: Photonics Review (20 18)) High brightness single photon light source and quantum control in micro-nano structure (Optics Express (2008) cited by ESI) and its applications (Nature Communications (2018), Phys. Rev Lite (20 14), etc.