Abstract
A fundamental understanding of the interplay between the microscopic structure and macroscopic optoelectronic properties of organic-inorganic hybrid perovskite materials is essential to design new materials and improve device performance. However, how exactly the organic cations affect the structural phase transition and optoelectronic properties of the materials is not well understood. Here, real-time, in situ temperature-dependent neutron/X-ray diffraction and photoluminescence (PL) measurements reveal a transformation of the organic cation CH3NH3 + from order to disorder with increasing temperature in CH3NH3PbBr3 perovskites. The molecular-level order-to-disorder transformation of CH3NH3 + not only leads to an anomalous increase in PL intensity, but also results in a multidomain to single-domain structural transition. This discovery establishes the important role that organic cation ordering has in dictating structural order and anomalous optoelectronic phenomenon in hybrid perovskites.
| Original language | English |
|---|---|
| Article number | 1705801 |
| Journal | Advanced Materials |
| Volume | 30 |
| Issue number | 22 |
| DOIs | |
| State | Published - May 29 2018 |
Funding
This research was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. The single-crystal neutron diffraction experiment was performed at the TOPAZ beamline of Oak Ridge National Laboratory’s Spallation Neutron Source, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Low-temperature DSC characterizations by B.Y. were supported by the Fundamental Research Funds for the Central Universities. DFT calculations by M.-H.D. and W.M. were supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. J.H. thanks the financial support from Defense Threat Reduction Agency (Award No. HDTRA1-14-1-0030). The authors thank C. Hoffmann and J. Yan for technical assistance and fruitful discussion. This research was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. The single-crystal neutron diffraction experiment was performed at the TOPAZ beamline of Oak Ridge National Laboratory's Spallation Neutron Source, which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Low-temperature DSC characterizations by B.Y. were supported by the Fundamental Research Funds for the Central Universities. DFT calculations by M.-H.D. and W.M. were supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. J.H. thanks the financial support from Defense Threat Reduction Agency (Award No. HDTRA1-14-1-0030). The authors thank C. Hoffmann and J. Yan for technical assistance and fruitful discussion.
Keywords
- optoelectronic properties
- organohalide perovskites
- phase transitions
- single crystal neutron diffraction
- solar cells
