Temperature-Dependent Electric Field Poling Effects in CH3NH3PbI3 Optoelectronic Devices

Organo-lead halide perovskites show excellent optoelectronic properties; however, the unexpected inconsistency in forward–backward I–V characteristics remains a problem for fabricating solar panels. Here we have investigated the reasons behind this “hysteresis” by following the changes in photocurre...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2017-04, Vol.8 (7), p.1429-1435
Main Authors: Zhang, Chuang, Sun, Dali, Liu, Xiaojie, Sheng, Chuan-Xiang, Vardeny, Zeev Valy
Format: Article
Language:English
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Summary:Organo-lead halide perovskites show excellent optoelectronic properties; however, the unexpected inconsistency in forward–backward I–V characteristics remains a problem for fabricating solar panels. Here we have investigated the reasons behind this “hysteresis” by following the changes in photocurrent and photoluminescence under electric field poling in transverse CH3NH3PbI3-based devices from 300 to 10 K. We found that the hysteresis disappears at cryogenic temperatures, indicating the “freeze-out” of the ionic diffusion contribution. When the same device is cooled under continuous poling, the built-in electric field from ion accumulation brings significant photovoltaic effect even at 10 K. From the change of photoluminescence upon polling, we found a second dipole-related mechanism which enhances radiative recombination upon the alignment of the organic cations. The ionic origin of hysteresis was also verified by applying a magnetic field to affect the ion diffusion. These findings reveal the coexistence of ionic and dipole-related mechanisms for the hysteresis in hybrid perovskites.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.7b00353