Abstract
Organic-inorganic hybrid perovskite solar cells based on CH3NH3PbI3 have achieved great success with efficiencies exceeding 20%. However, there are increasing concerns over some reported efficiencies as the cells are susceptible to current-voltage (I-V) hysteresis effects. It is therefore essential that the origins and mechanisms of the I-V hysteresis can clearly be understood to minimize or eradicate these hysteresis effects completely for reliable quantification. Here, a detailed electro-optical study is presented that indicates the hysteresis originates from lingering processes persisting from sub-second to tens of seconds. Photocurrent transients, photoluminescence, electroluminescence, quasi-steady state photoinduced absorption processes, and X-ray diffraction in the perovskite solar cell configuration have been monitored. The slow processes originate from the structural response of the CH3NH3PbI3 upon E-field application and/or charge accumulation, possibly involving methylammonium ions rotation/displacement and lattice distortion. The charge accumulation can arise from inefficient charge transfer at the perovskite interfaces, where it plays a pivotal role in the hysteresis. These findings underpin the significance of efficient charge transfer in reducing the hysteresis effects. Further improvements of CH3NH3PbI3-based perovskite solar cells are possible through careful surface engineering of existing TiO2 or through a judicious choice of alternative interfacial layers.
Original language | English |
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Article number | 1500829 |
Journal | Advanced Energy Materials |
Volume | 5 |
Issue number | 19 |
DOIs | |
Publication status | Published - Oct 7 2015 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
ASJC Scopus Subject Areas
- Renewable Energy, Sustainability and the Environment
- General Materials Science
Keywords
- charge accumulation
- hysteresis
- perovskite solar cells
- slow dynamics