Charge-selective-contact-dependent halide phase segregation in CsPbIBr2 perovskite solar cells and its correlation to device degradation

A Universal Grain “Cage” to Suppress Halide Segregation of Mixed-Halide Inorganic Perovskite Solar Cells

“…In contrast, the absorbance below 550 nm is nearly unchanged, and that over 600 nm is slightly increased (Figure b) for COF-containing perovskite film, evidently demonstrating the suppressed phase demixing behavior. All the above conclusions become more evident from the variation of absorption difference (Figure c,d, new phase formation for Δ A > 0 and photo bleaching of CsPbIBr 2 for Δ A < 0), which is derived by subtracting the initial absorbance spectrum before light exposure with the treated spectrum at various time . Although the phase segregation is a reversible process, as shown in Figure S10, the control film displays inferior recovery degree compared to that of the COF-containing film.…”

Healing the Buried Interface by a Plant-Derived Green Passivator for Carbon-Based CsPbIBr2 Perovskite Solar Cells

“…Figure a,b shows that the absorption intensity of the pristine film is decreased quickly at the wavelength range between 540 and 580 nm (Δ A < 0), together with the increased absorbance intensity at the wavelength range of 510–540 and 580–650 nm (Δ A > 0). The evolution of absorbance spectra illustrates that the homogeneous CsPbIBr 2 perovskite experiences serious phase segregation to I-rich and Br-rich phases under continuous light stimulation; , while the photoinduced phase segregation is suppressed with the smaller absorption variation when introduced to the ET molecule (Figure c,d), illustrating the mitigated halide segregation. In general, V I in the perovskite film acts as media to speed up the phase segregation because of the weaker and longer Pb–I bond than the Pb–Br bond .…”

How temperature impacts material properties and photovoltaic performance of mixed-halide perovskite via light-induced ion migration

“…Phase segregation has been reported to induce ionic accumulation at both the perovskite/ETL and the perovskite/HTL interfaces. [58][59][60][61] This carrier accumulation hinders charge transport and leads to the formation of PbI 2 upon prolonged illumination. Additionally, the thermal instability of spiro-OMeTAD also contributes to the degradation of PSCs at high temperatures.…”