Figure 3.

(a,b) UV-vis and photoluminescence (PL) spectra of Cs₂AgBiBr₆ films with and without annealing. As-prepared Cs₂AgBiBr₆ films were annealed at 150 °C, 250 °C and 300 °C for 30 min respectively. Inset in (a) is the Tuat plot obtained from the optical absorption spectrum. (c,d) UV-vis and PL spectra of Cs₂AgBiBr₆ films annealed at 300 °C for 5 min, 15 min, 30 min, and 65 min respectively. (e) UPS spectra of Cs₂AgBiBr₆ film annealed at 300 °C for 15 min. (f) Energy band diagram of Cs₂AgBiBr₆ solar cell with the planar structure of FTO/compact TiO₂/Cs₂AgBiBr₆/Spiro-OMeTAD/Ag.