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Title: Carrier Separation and Transport in Perovskite Solar Cells Studied by Nanometre-Scale Profiling of Electrical Potential

Organometal–halide perovskite solar cells have greatly improved in just a few years to a power conversion efficiency exceeding 20%. This technology shows unprecedented promise for terawatt-scale deployment of solar energy because of its low-cost, solution-based processing and earth-abundant materials. We have studied charge separation and transport in perovskite solar cells—which are the fundamental mechanisms of device operation and critical factors for power output—by determining the junction structure across the device using the nanoelectrical characterization technique of Kelvin probe force microscopy. Moreover, the distribution of electrical potential across both planar and porous devices demonstrates p–n junction structure at the TiO2/perovskite interfaces and minority-carrier diffusion/drift operation of the devices, rather than the operation mechanism of either an excitonic cell or a p-i-n structure. When we combined the potential profiling results with solar cell performance parameters measured on optimized and thickened devices, we find that carrier mobility is a main factor that needs to be improved for further gains in efficiency of the perovskite solar cells.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Brown Univ., Providence, RI (United States)
  3. Univ. of New Orleans, LA (United States)
Publication Date:
OSTI Identifier:
1225941
Report Number(s):
NREL/JA--5K00-64457
Journal ID: ISSN 2041-1723
Grant/Contract Number:
AC36-08GO28308; DMR-1305913
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 77 NANOSCIENCE AND NANOTECHNOLOGY charge separation; transport; perovskite solar cells; Kelvin probe force microscopy