1. • Stability is calculated by comparing energy of the bulk Perovskite to that of the PbI2
precipitate and salt (using Abinit code)
• The formability of the new perovskite is checked by using the Goldschmidt tolerance factor
(favourable structures are 0.76<t<1.13)[6]
• The band structures were calculated using Wien2k code
• The synthesis is done by mixing the solutions of Pb(NO)3 and excess of (CH3NH3)I[3]
• Addition of water to the perovskites results in decomposition as shown below[4]
• Current methods protect the Perovskite with polymer coating[5]
• Our approach to resolve this issue is to modify the material itself
Enhanced Chemical Stability of
Halide Perovskite Photovoltaics
E. Tenuta and O. Rubel
Thanks goes to Dr. Yurij Mozharivskyj, Dr. Emily Cranston and Dr. David Brock for their help on the finer points of chemistry
Introduction & Background
Method
Results and Discussion
R M X M R M
EF
Energy(eV)
0.0
1.0
2.0
3.0
-1.0
-2.0
R M X M R M
EF
Energy(eV)
0.0
1.0
2.0
3.0
-1.0
-2.0
R M X M R M
EF
Energy(eV)
0.0
1.0
2.0
3.0
-1.0
-2.0
R M X M R M
EF
Energy(eV)
0.0
1.0
2.0
3.0
-1.0
-2.0
Motivation • Improved stability via dissociation
• Reasonable, but not perfect band
gaps
• Consistent valence and
conduction band shapes
• Interesting result of S-N
interactions
Conclusion and Future Work
References
• New emerging photovoltaic material
(CH3NH3)PbI3in the Perovskite form
ABX3
• Perovskite has shown impressive
increases in efficiency in the past 3
years
• Known for high charge carrier mobilities,
high efficiency and other favorable photovoltaic properties[1] [2]
• Even though the LCOE for photovoltaic systems have dropped
exponentially since the 70’s the initial cost is still high enough to
deter people from investing
• The Perovskite material can be solution processed instead of the
conventional lithographic etchants on ultra thin wafers, this could
reduce the cost of production even further[1]
• Manipulation of the cation shows a direct link to both the stability and the band structures of
the material
• The secret to the stability of the Perovskite is not is the extra coatings needed to protect the
material but within the structure of the material itself
• The next step is to create a process for the synthesis of the material, along with creating the
actual material
CH3NH3
+ S2N+ SF3
+ SeF3
+
[1] You, J. ACS Nano. 2014, 8(2), 1674-1680
[2] Snaith H.J. Phys. Chem. Let.. 2013, 4, 3626-3630
[3] Vincent, B.R. Can. J. Chem. 1987, 65 1042-1046
[4] Niu,G. J. Mater. Chem. A, 2015, 3, 8970-8980
[5] Yang, J. ACS Nano. 2015, 9(2), 1955-1963
[6] Kim, H. J. Phys. Chem. 2014, 118, 5615-5625