Halide perovskites are promising semiconductors for inexpensive, high-performance optoelectronics. Despite a remarkable defect tolerance compared to conventional semiconductors, perovskite thin films still show substantial microscale heterogeneity in key properties such as luminescence efficiency and device performance. However, the origin of the variations remains a topic of debate, and a precise understanding is critical to the rational design of defect management strategies. Through a multi-scale investigation-combining correlative synchrotron scanning X-ray diffraction and time-resolved photoluminescence measurements on the same scan area-we reveal that lattice strain is directly associated with enhanced defect concentrations and non-radiative recombination. The strain patterns have a complex heterogeneity across multiple length scales. We propose that strain arises during the film growth and crystallization and provides a driving force for defect formation. Our work sheds new light on the presence and influence of structural defects in halide perovskites, revealing new pathways to manage defects and eliminate losses.
Bibliographical noteFunding Information:
TWJ acknowledges the Australian Renewable Energy Agency for a post-doctoral Fellowship. This project has received funding from the European Union’s Seventh Framework Programme (PIOF-GA-2013-622630), the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (HYPERION, grant agreement No. 756962), and the Royal Society and Tata Group (UF150033). GJW acknowledges the support of a CSIRO Julius Career Fellowship. TWJ and GJW acknowledge travel funding provided by the International Synchrotron Access Program (ISAP) managed by the Australian Synchrotron, part of ANSTO, and funded by the Australian Government. This work made use of the Shared Experimental Facilities supported in part by the MRSEC Program of the National Science Foundation under award number MDR – 1419807. This work was supported in part by the Yonsei University Future-leading Research Initiative of 2017-22-0088. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. We thank the European Synchrotron Radiation Facility (ESRF) for beamtime at the ID13 beamline and the beamline staff for measurement support. M. A.-J. thanks Nava Technology Limited, Cambridge Materials Limited and EPSRC (EP/M005143/1) for funding and technical support. AO acknowledges the NSF under Grant No. 1605406 (EP/L000202). M. A. received funding from The President of the UAE’s Distinguished Student Scholarship Program (DSS), granted by the Ministry of Presidential Affairs. This work was also supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2018R1C1B6008728).
© 2019 The Royal Society of Chemistry.