Rui Zhu

Perovskite & Organic devices

Peking University, Beijing, China

Email: iamzhurui@pku.edu.cn

Biography

Dr. Rui Zhu is a professor (tenured) at the Institute of Modern Optics, School of  Physics, Peking University. He was selected as the "Boya Young Scholar" of Peking University. He has  received  “Excellent  Young  Scholar  Award”  from  the  National  Natural  Science Foundation of China in 2017 and “Distinguished Young Scholar Award” from the Beijing Natural Science Foundation in 2021. His research is focusing on the topics related to perovskite solar cells. He has authored more  than  90  research  papers,  including  Science,  Nature  Reviews  Materials,  Nature Photonics, Nature Energy, Nature Communications, Advanced Materials and Nano Letters with over 10000 citations (h-index: 43). He has received 14 authorized Chinese patents. Several papers have been selected as the "China's Top 100 Most Influential International Academic Papers”, the “Beijing Area  Widely Concerned Academic Paper". He has 13 ESI highly cited papers and 2 ESI hot papers. He has won the 17th “Wang Daheng’s Optical Prize” for Young and Middle-Aged Scientists  (2020), the 9th “Yau Yuk-Tai Fundamental Optics  Award”  (second  class  prize,  2016),  the  “Chen  Huxiong’s  Young  Teacher  Award, School  of  Physics,  Peking  University”  (2017)  and  the  “Excellent  Doctoral  Dissertation Supervisor award of Peking University” (2017). 

Abstract for Presentation

The Critical Role of Organic Ammonium Halides in Perovskite Photovoltaics

In recent years, our research group keeps focusing on the development of highperformance  metal  halide  perovskite  solar  cells  (PSCs)  including  the  screen  of  the related optoelectronic materials and the optimization of devices as well as the study of chemical  and  physical  machnisim.  Organic  ammonium  halides  such  as methylammonium halides, formamidinium halides,  and other alkylammonium halides play a critical role in PSCs. On the one hand, they are the indispensable components to construct  the  2D or 3D  perovskite crystals and  are vital to  tune  the bandgaps of the perovskites. On the other hand, they can be utilized as dopants or additives to improve the perovskite films, which mainly involves three aspects:  (i) the optimization of onestep or two-step method perovskite precursor solution,  (ii) the  post-treatment of the perovskite film surface,  and  (iii)  the modification of the buried interface. Especially after 2017, the second aspect, that is, using organic ammonium halides to post-treat the perovskite film is regarded as the most effective way to passivate the  surface  defects for highly-efficient PSCs, becoming more and more popular in the field of PSCs. 

Our research group starts paying close attention to the study of improving PSCs using organic ammonium halides from 2015, and a  series of good results  have been achieved. For the (i) aspect, we developed some strategies such as (a) doping methylammonium bromide  into  the  lead  acetate-based  perovskite  precursor  solution  to  modulate  the crystallization, enhancing the optoelectronic properties of perovskite films, (b) adding guanidinium bromide into the all-inorganic perovskite precursor to induce spontaneous interfacial  manipulation,  optimizing  the  interfacial  contact,  and  (c)  introducing phenmethylammonium  iodide  into  the  organic  salt  solution  for  second  step  in  the sequential deposition to realize the passivation of grain boundary and interface, leading to ultra-long carrier lifetimes exceeding 6  μs.  For the (ii)  aspect,  we developed some strategies such as (a) post-treating  the perovskite film using guanidinium bromide to form  a  graded  junction  at  the  surface  region,  achieving  significantly  enhanced photovoltage  over  1.20  V,  (b)  polishing  the  perovskite  surface  with  a phenmethylammonium  iodide-containing  chemical  polishing  agent  to  decouple  the double-edged  sword  effect  of  excess  PbI2,  realizing  improved  photovoltaic performances and device stability.  For the (iii)  aspect, utilizing phenethylammonium bromide  to treat the organic hole transport layer and construct 2D perovskite at the buried interface, remarkably increasing the performances of tin-based PSCs. To further study the buried clearly and directly, we then developed a  characterizing platform for the buried interface  for the first time, and found surface post-treatment could lead to the molecule-assisted microstructural reconstruction  and  simultaneously optimize the buried  interface.  Inspired by the interest new results in this work, we began to realize that  the  modification  of  the  buried  interface  is  of  equal  importance  to  the  surface modification.  Then we developed a depth-dependent defect manipulation  strategy using a binary modulator system with selective penetrability within polycrystalline perovskite films, which  can concurrently passivate the defects  both in bulk and at interfaces to boost the performances of PSCs.

References

[1] L. Zhao # , D. Luo # , J. Wu, Q. Hu, W. Zhang, K. Chen, T. Liu, Y. Liu, Y. Zhang, F. Liu, T.P. Russell*, H.J. Snaith, R. Zhu*, Q. Gong, Adv. Funct. Mater., 26 (2016) 3508.

[2] Y. Zheng, X. Yang, R. Su, P. Wu, Q. Gong, R. Zhu*, Adv. Funct. Mater., 30 (2020) 2000457.

[3] X. Yang # , Y. Fu # , R. Su, Y. Zheng, Y. Zhang, W. Yang, M. Yu, P. Chen, Y. Wang, J. Wu, D. Luo, Y. Tu, L. Zhao*, Q. Gong, R. Zhu*, Adv. Mater., 32 (2020) 2002585.

[4] D. Luo # , W. Yang # , Z. Wang # , A. Sadhanala, Q. Hu, R. Su, R. Shivanna, G.F. Trindade, J.F. Watts, Z. Xu, T. Liu, K. Chen, F. Ye, P. Wu, L. Zhao, J. Wu, Y. Tu, Y. Zhang, X. Yang, W. Zhang*, R.H. Friend, Q. Gong, H.J. Snaith*, R. Zhu*, Science, 360 (2018) 1442.

[5] D. Luo # , R. Su # , W. Zhang*, Q. Gong, R. Zhu*, Nat. Rev. Mater., 5 (2020) 44.

[6] K. Chen # , P. Wu # , W. Yang, R. Su, D. Luo, X. Yang, Y. Tu,  R. Zhu*, Q. Gong, Nano Energy, 49 (2018) 411.

[7] X. Yang # , D. Luo # , Y. Xiang # , L. Zhao, M. Anaya, Y. Shen, J. Wu, W. Yang, Y. -H. Chiang, Y. Tu, R. Su, Q. Hu, H. Yu, G. Shao, W. Huang, T.P. Russell, Q. Gong*, S.D. Stranks, W. Zhang*, R. Zhu*, Adv. Mater., 33 (2021) 2006435.

[8] Y. Zhang # , Y. Wang # , L. Zhao*, X. Yang, C.-H. Hou*, J. Wu, R. Su, S. Jia, J.-J. Shyue, D. Luo, P. Chen, M. Yu, Q. Li, L. Li, Q. Gong, R. Zhu*, Energy Environ. Sci., 14 (2021) 6526.

[9] L. Zhao # , Q. Li # , C.-H. Hou, S. Li, X. Yang, J. Wu, S. Zhang, Q. Hu, Y. Wang, Y. Zhang, Y. Jiang, S. Jia, J.-J. Shyue, T.P. Russell, Q. Gong, X. Hu, R. Zhu*, J. Am. Chem. Soc., 144 (2022) 1700.