Influence of Work Function of Carrier Transport Materials with Perovskite on Switchable Photovoltaic Phenomena
Journal
Journal of Physical Chemistry C
Date Issued
2019
Author(s)
Abstract
The hysteresis effect and switchable photovoltaic phenomena in organo-metal halide perovskite have been observed in perovskite solar cells with certain structures and under certain measure conditions. These phenomena were favorably applied to resistive random-access memory and human-brain-mimicking devices, especially using photons as a reading or stress probe apart from using electrical probe. However, the mechanisms causing these effects are not fully understood. In this paper, the perovskite devices with different hole transporting layers, which have the work functions ranging from 5.9 to 3.7 eV, were fabricated and systematically characterized by current-voltage measurements and time-resolved photoresponse measurements. These measurements show that the switchable photovoltaic phenomena are highly related to the work function of the hole transporting layer. The interfacial electronic structures of perovskite and several materials were studied in details using X-ray and ultraviolet photoemission spectroscopy (XPS and UPS), suggesting that the switchable photovoltaic is extensively dependent on the strong band bending effect. Light-mediated XPS measurements reveals that the degree of band bending in the perovskite layer was manipulated by charge trapping/detrapping and hole-carrier accumulation. Based on the electrical measurements and band diagram, we propose a model that combines ion migration and charge trapping/detrapping processes to explain the switchable photovoltaic phenomena. © 2019 American Chemical Society.
SDGs
Other Subjects
Charge trapping; Electronic structure; Hole mobility; Metal halides; Perovskite; Perovskite solar cells; Photoelectron spectroscopy; Probes; Random access storage; Solar power generation; Work function; X ray photoelectron spectroscopy; Charge trapping/detrapping; Current voltage measurement; Electrical measurement; Hole transporting layers; Interfacial electronic structure; Photoresponse measurements; Resistive random access memory; Ultraviolet photoemission spectroscopy; Photovoltaic effects
Type
journal article