Multifunctional Two-Dimensional Benzodifuran-Based Polymer for Eco-Friendly Perovskite Solar Cells Featuring High Stability

Abstract

Perovskite solar cells (PSCs) have been regarded as an exceptional renewable energy conversion technology due to their rapidly increasing photovoltaic efficiency, while their practical application is highly retarded by their intrinsic instability and potential lead ion leakage. Here, a two-dimensional (2D) π-conjugated benzodifuran-based polymer, PBDFP-Bz, is adopted to modify the perovskite film. Note that PBDFP-Bz could neutralize surface defects, fine-tune interfacial energetics, and hamper moisture ingression into the perovskite film. Therefore, high-quality perovskite films featuring reduced trap state density and enhanced moisture tolerance could be obtained after modification via PBDFP-Bz. Consequently, PBDFP-Bz-modified devices deliver a higher efficiency of 21.73% versus 19.55% of control ones. Meanwhile, PBDFP-Bz-modified devices can preserve 82.7 and 90.8% of their initial efficiency under continuous heating at 85 °C or light soaking for 500 h. However, the corresponding retained values of control devices are only 56.4 and 70.2%, respectively. Moreover, PBDFP-Bz can effectively prevent the leakage of lead ions in modified devices relative to control ones. This work not only reveals that PBDFP-Bz features high potential for fabricating high-performance and robust PSCs but also indicates that 2D π-conjugated benzodifuran-based polymers can endow PSCs with great security for sustainable development without the concern of lead ion leakage.

Sustainable and environmentally viable perovskite solar cells

“…Two-dimensional (2D) π-conjugated PBDFP-Bz with abundant functional groups can interact strongly with the perovskite film surface to neutralize surface defects. 86 FTIR measurements confirmed that the C-H, C-O, and C-F bonds in PBDFP-Bz interacted with PbI 2 to prevent lead leakage. After immersing the device with PBDFP-Bz in DI water for 7200 min, the lead concentration in the DI water was detected to be 18.9 ppm, which is much lower than that of the control device (>60 ppm).…”

“…Two‐dimensional (2D) π‐conjugated PBDFP‐Bz with abundant functional groups can interact strongly with the perovskite film surface to neutralize surface defects 86 . FTIR measurements confirmed that the C‐H, C‐O, and C‐F bonds in PBDFP‐Bz interacted with PbI 2 to prevent lead leakage.…”

Hole-Transport Management Enables 23%-Efficient and Stable Inverted Perovskite Solar Cells with 84% Fill Factor

“…Despite much effort, unluckily, device operational stability has been main bottleneck for further development. For example, external encapsulation strategy as a necessary craft process not only can prevent the infiltration of moisture and oxygen, but also enable lead sequestration, thus enhancing the environmental stability of perovskites [ 21 – 23 ]. Nevertheless, PSCs treated under continuous light illumination still show poor operational stability, though devices were dealt with external encapsulation.…”

Bidirectional Targeted Therapy Enables Efficient, Stable, and Eco‐Friendly Perovskite Solar Cells

“…As presented in Figure 2e, the stretching vibration of CH bond in 1,4-dithiane presents positive shift from 2985/2910 to 3000/2920 cm −1 in the 1,4-dithiane/ PbI 2 complex (Figure 2e). [34] Meanwhile, the stretching vibration of PbI bond in PbI 2 shifts from 2931/2861 cm −1 toward higher wavenumber of 2973/2872 cm −1 (Figure 2e; Figure S8, Supporting Information). However, the stretching vibration of CS bond in pure 1,4-dithiane shifts from 903 cm −1 to lower wavenumber of 898 cm −1 when complexed with PbI 2 (Figure 2f).…”