Abstract
Tin-lead perovskites have low band gaps (1.2 eV - 1.4 eV) that offer complementary absorption spectra to mixed halide perovskites with band gaps in the range of 1.6 eV - 1.85 eV. In combination, tin-lead and mixed halide perovskites can be used to make efficient all-perovskite tandem solar cells. While these can achieve high efficiency, they are hampered by the unproven longterm stability of tin-containing perovskites. We make the first demonstration of tin-lead perovskite solar cells that pass benchmark 1000-hour tests of stability under stressors of heat, light, and atmospheric exposure. We identify that mixed tin-lead perovskites oxidise by a different chemical pathway, one that is much less favourable, than the oxidation pathway followed by pure tin perovskites, making them significantly more stable. Fortuitously, mixed tin-lead perovskites also have band gaps that are close to ideal for the rear cell of an all-perovskite monolithic two-junction tandem. Beyond selecting the composition of the perovskite to be one that has inherently suppressed tendency to oxidise, we also fabricate a novel heterojunction-based architecture that eliminates the commonly used acidic PEDOT:PSS layer, which leads to enhanced stability. By packaging the resulting solar cell in a glass-on-glass package with a pliable low-elastic-modulus polyolefin encapsulant and a butyl rubber edge seal, we also demonstrate that the low band gap perovskite solar cell that passes the IEC damp heat test for thin film solar cells - a milestone that demonstrates the removal of a significant impediment to the commercialization of high efficiency perovskite tandem solar cells.
Original language | American English |
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Pages | 2359-2361 |
Number of pages | 3 |
DOIs | |
State | Published - Jun 2019 |
Event | 46th IEEE Photovoltaic Specialists Conference, PVSC 2019 - Chicago, United States Duration: 16 Jun 2019 → 21 Jun 2019 |
Conference
Conference | 46th IEEE Photovoltaic Specialists Conference, PVSC 2019 |
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Country/Territory | United States |
City | Chicago |
Period | 16/06/19 → 21/06/19 |
Bibliographical note
Publisher Copyright:© 2019 IEEE.
NREL Publication Number
- NREL/CP-5900-76332
Keywords
- energy gap
- organic semiconductors
- solar cells
- tin compounds