Invited Speech:

A new room temperature approach for forming high performance CH₃NH₃PbI₃ solar cells with good productivity and stability

W.C. H. Choy, H. Zhang

Prof. Wallace C.H. Choy Professor Department of Electrical and Electronic Engineering, The University of Hong Kong E-mail: chchoy@eee.hku.hk

Date: 13 Dec 2016 (Tue)
Time: 10:15 - 10:45am
Venue: TY Wong Hall, 5/F, Ho Sin Hang Engineering Building, CUHK

Abstract:

Recently, researchers have focused more to design highly efficient flexible perovskite solar cells (PVSCs), which enables the implementation of portable and roll-to-roll fabrication in large scale. We will report new room temperature approaches for forming perovskite solar cells. Regarding  hole transport layer (HTL), NiOx is a promising material for candidate for fabricating efficient PVSCs on rigid substrate, the reported NiOx HTLs are formed using different multi-step treatment (such as 300-500 degC annealing O2-plasma, UVO etc.), which hindering the development of flexible PVSCs based on NiOx. Meanwhile, the features of nanostructured morphology and flawless film quality are very important for the film to function as highly effective HTL of PVSCs. However, it is difficult to have the two features co-exist natively particularly in solution process that flawless film will usually come with smooth morphology. Here, we demonstrate the flawless and surface-nanostructured NiOx film from a simple and controllable room-temperature solution process.

Meanwhile, we will propose a new room temperature scheme formation of perovskite films with the features of PbI2 residue-free, large grain-sizes, and highly crystalline. We further layout the design rules for the broad, rational extension of our scheme to form high-quality perovskite films. Using our approach, a room-temperature processed PVSC with no hysteresis, high power conversion efficiency of 17.10% which is the best of the perovskite solar cells fabricated by low-temperature techniques to date. Additionally, the device is very stable with performance maintance of 95% after 1000 hours. This work contributes to the large-sale and low-cost production of perovskite solar cells with high device performances.