TY - JOUR
T1 - Vacancy-Ordered Double Perovskite Cs2TeI6 Thin Films for Optoelectronics
AU - Vázquez-Fernández, Isabel
AU - Mariotti, Silvia
AU - Hutter, Oliver
AU - Birkett, Max
AU - Veal, Tim D.
AU - Hobson, Theodore D.C.
AU - Phillips, Laurie J.
AU - Danos, Lefteris
AU - Nayak, Pabitra K.
AU - Snaith, Henry J.
AU - Xie, Wei
AU - Sherburne, Matthew P.
AU - Asta, Mark
AU - Durose, Ken
PY - 2020/8/11
Y1 - 2020/8/11
N2 - Alternatives to lead- and tin-based perovskites for photovoltaics and optoelectronics are sought that do not suffer from the disadvantages of toxicity and low device efficiency of present-day materials. Here we report a study of the double perovskite Cs2TeI6, which we have synthesized in the thin film form for the first time. Exhaustive trials concluded that spin coating CsI and TeI4 using an antisolvent method produced uniform films, confirmed as Cs2TeI6 by XRD with Rietveld analysis. They were stable up to 250 °C and had an optical band gap of ∼1.5 eV, absorption coefficients of ∼6 × 104 cm-1, carrier lifetimes of ∼2.6 ns (unpassivated 200 nm film), a work function of 4.95 eV, and a p-type surface conductivity. Vibrational modes probed by Raman and FTIR spectroscopy showed resonances qualitatively consistent with DFT Phonopy-calculated spectra, offering another route for phase confirmation. It was concluded that the material is a candidate for further study as a potential optoelectronic or photovoltaic material.
AB - Alternatives to lead- and tin-based perovskites for photovoltaics and optoelectronics are sought that do not suffer from the disadvantages of toxicity and low device efficiency of present-day materials. Here we report a study of the double perovskite Cs2TeI6, which we have synthesized in the thin film form for the first time. Exhaustive trials concluded that spin coating CsI and TeI4 using an antisolvent method produced uniform films, confirmed as Cs2TeI6 by XRD with Rietveld analysis. They were stable up to 250 °C and had an optical band gap of ∼1.5 eV, absorption coefficients of ∼6 × 104 cm-1, carrier lifetimes of ∼2.6 ns (unpassivated 200 nm film), a work function of 4.95 eV, and a p-type surface conductivity. Vibrational modes probed by Raman and FTIR spectroscopy showed resonances qualitatively consistent with DFT Phonopy-calculated spectra, offering another route for phase confirmation. It was concluded that the material is a candidate for further study as a potential optoelectronic or photovoltaic material.
U2 - 10.1021/acs.chemmater.0c02150
DO - 10.1021/acs.chemmater.0c02150
M3 - Article
C2 - 32952296
SN - 0897-4756
VL - 32
SP - 6676
EP - 6684
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 15
ER -