Tailoring of a visible-light-absorbing biaxial ferroelectric towards broadband self-driven photodetection

Shiguo Han,Junhua Luo,Zhihua Sun,Wuqian Guo,Mao-Chun Hong,Maofan Li,Yi Liu

doi:10.1038/s41467-020-20530-4

Abstract

In terms of strong light-polarization coupling, ferroelectric materials with bulk photovoltaic effects afford a promising avenue for optoelectronic devices. However, due to severe polarization deterioration caused by leakage current of photoexcited carriers, most of ferroelectrics are merely capable of absorbing 8–20% of visible-light spectra. Ferroelectrics with the narrow bandgap (<2.0 eV) are still scarce, hindering their practical applications. Here, we present a lead-iodide hybrid biaxial ferroelectric, (isopentylammonium)2(ethylammonium)2Pb3I10, which shows large spontaneous polarization (~5.2 μC/cm2) and a narrow direct bandgap (~1.80 eV). Particularly, the symmetry breaking of 4/mmmFmm2 species results in its biaxial attributes, which has four equivalent polar directions. Accordingly, exceptional in-plane photovoltaic effects are exploited along the crystallographic [001] and [010] axes directions inside the crystallographic bc-plane. The coupling between ferroelectricity and photovoltaic effects endows great possibility toward self-driven photodetection. This study sheds light on future optoelectronic device applications.

Highlights

In terms of strong light-polarization coupling, ferroelectric materials with bulk photovoltaic effects afford a promising avenue for optoelectronic devices
High-quality dark red crystals of PEPI were grown by the temperature cooling method (Supplementary Fig. 1), and the phase purity and thermal stabilities have been confirmed by powder Xray diffraction and thermogravimetric analysis, respectively (Supplementary Fig. 2 and Supplementary Fig. 3)
It is obvious that both the direction of Voc and in-plane BPVEs. Short-circuit photocurrent (Isc) can be reversed by inverting electric poling, while the magnitude keeps almost unchanged (Fig. 7b)

Summary

Introduction

In terms of strong light-polarization coupling, ferroelectric materials with bulk photovoltaic effects afford a promising avenue for optoelectronic devices. Due to severe polarization deterioration caused by leakage current of photoexcited carriers, most of ferroelectrics are merely capable of absorbing 8–20% of visible-light spectra. Bulk photovoltaic effects (BPVE) of ferroelectric materials is a strong light-polarization coupling with unique physical attributes[1,2,3,4], including ultrahigh anomalous photovoltage, polarization-dependent activity, and steady-state photocurrent in a homogeneous media, etc. 60 years, BPVE-active ferroelectrics with the Eg smaller than 2.0 eV remain scarce In this context, significant endeavors should be focused on exploring the visible-light-absorbing ferroelectric candidates with strong BPVEs, because the current leakage of photoexcited charge carriers will cause severe deterioration of electric polarization.

Methods

Results

Conclusion