Amorphous TiO2 Compact Layers via ALD for Planar Halide Perovskite Photovoltaics.
A low-temperature (<120 °C) route to pinhole-free amorphous TiO2 compact layers may pave the way to more efficient, flexible, and stable inverted perovskite halide device designs. Toward this end, we utilize low-temperature thermal atomic layer deposition (ALD) to synthesize ultrathin (12 nm) compact TiO2 underlayers for planar halide perovskite PV. Although device performance with as-deposited TiO2 films is poor, we identify room-temperature UV-O3 treatment as a route to device efficiency comparable to crystalline TiO2 thin films synthesized by higher temperature methods. We further explore the chemical, physical, and interfacial properties that might explain the improved performance through X-ray diffraction, spectroscopic ellipsometry, Raman spectroscopy, and X-ray photoelectron spectroscopy. These findings challenge our intuition about effective electron selective layers as well as point the way to a greater selection of flexible substrates and more stable inverted device designs.
Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.|Argonne-Northwestern Solar Energy Research (ANSER) Center , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
In Soo
IS
Kim
Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
Richard T
RT
Haasch
Argonne-Northwestern Solar Energy Research (ANSER) Center , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Duyen H
DH
Cao
Argonne-Northwestern Solar Energy Research (ANSER) Center , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Omar K
OK
Farha
Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.|Argonne-Northwestern Solar Energy Research (ANSER) Center , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Joseph T
JT
Hupp
Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.|Argonne-Northwestern Solar Energy Research (ANSER) Center , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Mercouri G
MG
Kanatzidis
Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.|Argonne-Northwestern Solar Energy Research (ANSER) Center , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Alex B F
AB
Martinson
amorphous titanium dioxide; atomic layer deposition; hybrid perovskites; low temperature processing; solar energy conversion