Liyuan Han

Perovskite & Organic devices

State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, China

Email: Han.liyuan@sjtu.edu.cn

Biography

Dr. Liyuan Han is the chair professor of Shanghai Jiao Tong University. He received his Ph.D. degree from the University of Osaka Prefecture,  and  had been worked at SHARP Corporation for 15 years, starting on the research of solar cells. In 2008, he moved to National Institute for Materials Science, Japan, and established a research center of next generation solar cells. He moved to current position in 2011. He is an inventor of more than 150 patents and an author in ca 300 scientific papers on  toplevel  journals  such  as  Science,  Nature,  Nature  Energy,  Energy  &  Environmental Science,  and  Advanced Materials  in the field of next generation solar cells.  He is selected as a highly cited researcher during 2019-2021. His current research interests involve fundamental research in perovskite solar cells and to fabricate large-area, highly efficient and stable perovskite solar cells for commercialization.

Abstract for Presentation

Highly efficient and stable perovskite solar cells

At present, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has reached 25.7%, and the long-term operational stability has also been improved. A number of research teams both at home and abroad began to make continuous efforts for its commercialization in the future. However, the commercialization of perovskite solar cells depends on the cost of electricity ultimately. According to our calculations, the cost of electricity is inversely proportional to the efficiency and lifetime of the solar cells. Therefore, further  improving the PCE and stability of perovskite solar cells are two key factors for their commercialization. Both efficiency and stability are closely related to the quality of the perovskite absorption layer, defect density and ion migration in  the  PSCs.  In  this  report,  I  will  introduce  our  team's  recent  research  progress  in perovskite crystal growth, defect passivation and ion migration inhibition:

(1) In order to further improve the crystal quality of perovskite thin films, we first prepared high-quality seed crystal arrays with regular and controllable arrangement on the  substrate.  The  seeds  regularly  distributed  on  the  substrate  induced  a  bottom -up crystallization process, resulting in a perovskite film with large grains (average grain size was 3  μm), high crystallinity and low defect density. PSCs made from suchlike high-quality perovskite film achieved a high PCE more than 25%.

(2)  We  developed  a  novel  and  low-cost  passivation  technique,  which  achieved uniform P-doping of spiro, and uniformly passivated  the front interface, grain boundary and back interface of perovskite simultaneously. As a result, we achieved high certified efficiency of 23.4% on 1 cm2 PSCs. In addition, our team designed an organic small molecule  (IT -Cl)  with  self-assembly  properties,  thus  forming  an  effective  defect modification network at the buried interface of perovskite films.

(3)  Improving  the  stability  of  highly  efficient  PSCs  is  essential  to  realize commercialization in the future, and ion migration is an important issue affecting the long-term stability of PSCs. To this end, our team designed a Cu-Ni alloy electrode protected  by  double-sided  graphene,  which  not  only  protected  the  electrode  from internal ions of perovskite, but also from external water and oxygen. As a result, our solar cell (1cm2 device with efficiency over 24%) showed excellent stability for 5000 hours under continuous light illumination.

References

[1]  Cai et al. Adv. Sci. 4, 1600269(2017).

[2]  Shen et al. Energy Environ. Sci., 15, 1078(2022).

[3]  Luo et al. Adv. Mater. 2022. Online. DOI: 10.1002/adma.202202100.

[4]  Su et al. Sci. China Chem. 2022. Online. DOI: 10.1007/s11426-022-1244-y.

[5]  E. Bi et al. Nat. Commun., 8, 15330(2017).

[6]  Y. Wang et al., Science., 365, 687-691(2019).

[7]  E. Bi., Joule, 3, 2748-2760 (2019).