Hybrid crystalline-ITO/metal nanowire mesh transparent electrodes and their application for highly flexible perovskite solar cells

Hyeon-Gyun Im,Il-Doo Kim,Jungho Jin,Jung-Yong Lee,Hyo-Joong Kim,Jaemin Lee,Daewon Lee,Byeong-Soo Bae,Seonju Jeong,Han-Ki Kim,Sin-Bi Kang,Junho Jang,Won-Tae Koo,Doo-Young Youn

doi:10.1038/am.2016.85

Abstract

Reinforcing transparent electrodes with a nanowire mesh brings solar cells that can wrap around objects one step closer to production. Indium tin oxide (ITO) is a rarity among metal oxide crystals – it is optically transparent and conductive enough to serve as electrodes in flat-panel displays and solar cells. Byeong-Soo Bae from the Korea Advanced Institute of Science and Technology and co-workers have now discovered how to make ITO into 10-nanometre-thin, flexible electrodes using a resin embedded with metal nanowires. Normally, the high temperatures needed to produce ITO crystals degrade flexible polymer substrates. But the nanowires impart sufficient mechanical strength to keep the electrodes pliant after ITO heat treatment. Depositing perovskite-type crystals onto the electrodes enabled the researchers to fabricate bendable solar cells with power conversion efficiencies of 12-14%.

Highlights

Transparent conducting electrodes (TCEs) with excellent mechanical robustness will be an essential component for the generation of flexible and stretchable optoelectronic devices, such as photovoltaic cells, light emitting devices and touch screen panels.[1,2,3,4,5] Indium tin oxide (ITO) has unambiguously been the most widely used TCE material because of its optical transparency, thermal/chemical stability and device compatibility, coupled with its well-established fabrication processes.[6,7] the brittle nature of ITO might limit its role in future devices.[8]
TCE, the optoelectrical performance was retained after introducing the c-ITO layer. These results suggest that the optoelectrical performance degradation of metal oxide/metal NW TCEs can be minimized if the figure of merit (FoM) difference between the metal oxide and the metal NW is small
The commercial ITO/polyethylene terephthalate (PET) sample (150 nm of ITO on 200 μm of PET) started to crack at r = 5.5 mm. These results indicate that the mechanical durability of the metal oxide/metal NW TCEs is limited by the thickness of the metal oxide layer, and a c-ITO layer thickness of o20 nm is necessary for the flexibility of the hybrid TCE

Summary

Introduction

Transparent conducting electrodes (TCEs) with excellent mechanical robustness will be an essential component for the generation of flexible and stretchable optoelectronic devices, such as photovoltaic cells, light emitting devices and touch screen panels.[1,2,3,4,5] Indium tin oxide (ITO) has unambiguously been the most widely used TCE material because of its optical transparency, thermal/chemical stability and device compatibility, coupled with its well-established fabrication processes.[6,7] the brittle nature of ITO might limit its role in future devices.[8]. The Rsh value (17.2 Ω sq − 1) of the hybrid electrodes was less than that of parallel-connected ITO (162 Ω sq − 1) or that of a NW network (81 Ω sq − 1), implying that AgNWs were further welded during the Introducing a metal oxide to a metal NW leads to the optoelectrical performance degradation of the TCE because of the resistivity of the metal oxides that is higher than that of the metal NWs.[28,29] To determine the effect of the c-ITO layer on the optoelectrical performance, the total transmittance at 550 nm (Ttot) of the c-ITO/ metal NW-GFRHybrimer films with varying ITO thicknesses (10, 20 and 30 nm) was measured with respect to the bare GFRHybrimer.

Results

Conclusion