Polyaniline/Reduced Graphene Oxide Composites for Hole Transporting Layer of High-Performance Inverted Perovskite Solar Cells

Jae Woong Jung,Seung Hwan Son,Jun Choi

doi:10.3390/polym13081281

Jae Woong Jung, Seung Hwan Son + Show 1 more

Open Access

https://doi.org/10.3390/polym13081281

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Abstract

We herein address the optoelectronic properties of polyaniline composite films with graphene oxide and reduced graphene oxide as a hole transport layer in inverted perovskite solar cells. The composite films exhibited enhanced electrical conductivity and suitable energy level matching with CH3NH3PbI3 for efficient hole extraction/transport than the pristine polyaniline film, which thus can deliver improved photovoltaic properties of device. The composite film-based devices exhibited maximum efficiency of 16.61%, which is enhanced by 21.6% from the device with the pristine polyaniline hole transport layer (efficiency = 13.66%). The reduced graphene oxide-based composite film also achieved improved long-term operative stability as compared to the pristine polyaniline-based device, demonstrating a great potential of reduced graphene oxide/polyaniline composite hole transport layer for high performance perovskite solar cells.

Highlights

Organometallic trihalide perovskites have been regarded as a representative nextgeneration photoactive material for photovoltaic applications, due to their unique optoelectronic properties such as intense light absorptivity, excellency in carrier transport and diffusion length, diversity in structure, and proper optical band gap [1,2]
The most well-established device structure of perovskite solar cells (PSCs) with high efficiency is a regular structure in which the transparent conductive oxide (TCO) cathode is modified with the metal oxide-based electron transport layer (ETL) (e.g., TiO2 or SnO2) for efficient electron transport from the perovskite absorber layer
This study demonstrated the utilization of PANI/graphene nanocomposite films as a hole transport layer (HTL) of the inverted PSCs

Summary

Introduction

Organometallic trihalide perovskites have been regarded as a representative nextgeneration photoactive material for photovoltaic applications, due to their unique optoelectronic properties such as intense light absorptivity, excellency in carrier transport and diffusion length, diversity in structure, and proper optical band gap [1,2]. It has been reported that the work function of PEDOT:PSS (~4.4 eV) is not well balanced with the energy levels of perovskite absorbers (~−3.9 and −5.4 eV for conduction and valence band, respectively, for CH3NH3PbI3), which may limit the full potential of open-circuit voltage (VOC) and resultant PCEs of PSCs [11] To resolve these issues, HTL engineering has been vigorously studied for the last decade. A composite film of PEDOT:PSS/ PANI/graphene oxide (GO) has accomplished balanced energy level matching and increased electrical conductivity, which demonstrated an excellent HTLs in the inverted PSCs with a PCE of 18.12% [21]. The composite HTLs exhibited negligible J-V hysteresis and high long-term stability in ambient condition without encapsulation, which promises the potential of PANI/graphene composite for applications in perovskite optoelectronics

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