Foam-like 3D Graphene as a Charge Transport Modifier in Zinc Oxide Electron Transport Material in Perovskite Solar Cells

Mohamed Salleh Mohamed Saheed,Mohamed Shuaib Mohamed Saheed,Qamar Wali,Rajan Jose,Balbir Singh Mahinder Singh,Norani Muti Mohamed

doi:10.3390/photochem1030034

Abstract

The effect of foam-like 3D graphene (3DG) in an electron transport material (ETM), viz. ZnO thin film, on the steady-state photoluminescence (PL), light-harvesting efficiency (LHE), photocurrent density (JSC), photovoltage (VOC), and charge transport parameters of perovskite solar cells (PSCs) are systematically investigated. The ETM is developed by spin coating a ZnO precursor solution containing varying amounts of 3DG on conducting glass substrates and appropriate annealing. A significant improvement in the photoconversion efficiency of PSCs is observed for a low concentration of 3DG in ZnO. The current–voltage and electrochemical impedance spectroscopy measurements show that the addition of 3DG enhances the VOC due to efficient electron–hole separation and charge transport compared to the pristine ZnO. These studies offer a route for further advances in enhancing the optoelectronic properties of ETM for artificial photosynthesis and photocatalysis devices.

Highlights

Ever since the first introduction of next-generation perovskite solar cell (PSC) by Kojima et al in 2009, Reference [1] a rapid development in organometallic perovskite-based solar cells were carried out to push the efficiency from 3.81% to over 25% [2,3,4]
It is of paramount importance to control the PSC material interfacial connection in order to lower the electron–hole recombination, prolong the excited electron life time, and eventually increases the current–density and photovoltage [6,7]
The morphology of the ZnO-3D graphene (3DG) was determined via field emission scanning electron microscope

Summary

Introduction

Ever since the first introduction of next-generation perovskite solar cell (PSC) by Kojima et al in 2009, Reference [1] a rapid development in organometallic perovskite-based solar cells were carried out to push the efficiency from 3.81% to over 25% [2,3,4]. It is of paramount importance to control the PSC material interfacial connection in order to lower the electron–hole recombination, prolong the excited electron life time, and eventually increases the current–density and photovoltage [6,7]. Various potential electron-transporting materials (ETMs) were developed such as the commonly known TiO2 , ZnO, SnO2 , PCBM, and other more complex materials [4,8,9,10,11,12,13,14,15]. With regard to photocurrent extraction, many researchers synthesized TiO2 in the form of thin film, nanotubes, nanoarrays, and other nanostructures as well as doping to reduce the charge recombination and to increase the photocurrent extraction efficiency [16,17,18,19,20]. ZnO exhibited higher electron mobility compared to TiO2 and better electron extraction capability, which makes it the ETM of choice [23,24,25,26,27]

Results

Discussion

Conclusion