posted on 2019-12-18, 22:29authored byYongtao Qu, See Wee Chee, Martial Duchamp, Stephen Campbell, Guillaume Zoppi, Vincent Barrioz, Yvelin Giret, Thomas J. Penfold, Apoorva Chaturvedi, Utkur Mirsaidov, Neil S. Beattie
Cu2ZnSnS4 nanocrystals are annealed
in a
Se-rich atmosphere inside a transmission electron microscope. During
the heating phase, a complete S–Se exchange reaction occurs
while the cation sublattice and morphology of the nanocrystals are
preserved. At the annealing temperature, growth of large Cu2ZnSnSe4 grains with increased cation ordering is observed
in real-time. This yields an annealing protocol which is transferred
to an industrially similar solar cell fabrication process resulting
in a 33% increase in the device open circuit voltage. The approach
can be applied to improve the performance of any photovoltaic technology
that requires annealing because of the criticality of the process
step.