Dual Role of Cu‐Chalcogenide as Hole‐Transporting Layer and Interface Passivator for p–i–n Architecture Perovskite Solar Cell

Abstract

Inorganic hole-transport layers (HTLs) are widely investigated in perovskite solar cells (PSCs) due to their superior stability compared to the organic HTLs. However, in p-i-n architecture when these inorganic HTLs are deposited before the perovskite, it forms a suboptimal interface quality for the crystallization of perovskite, which reduces device stability, causes recombination, and limits the power conversion efficiency of the device. The incorporation of an appropriate functional group such as sulfurterminated surface on the HTL can enhance the interface quality due to its interaction with perovskite during the crystallization process. In this work, a bifunctional Al-doped CuS film is wet-deposited as HTL in p-i-n architecture PSC, which besides acting as an HTL also improves the crystallization of perovskite at the interface. Urbach energy and light intensity versus open-circuit voltage characterization suggest the formation of a better-quality interface in the sulfide HTL-perovskite heterojunction. The degradation behavior of the sulfide-HTL-based perovskite devices is studied, where it can be observed that after 2 weeks of storage in a controlled environment, the devices retain close to 95% of their initial efficiency.

Evaluation of the Passivation Effects of PEDOT:PSS on Inverted Perovskite Solar Cells

“…The work function is calculated from the binding energy cutoff (E cutoff ) and the onset energy. [62,63] So, the valance band maximum (VBM) value is −5.40 eV for perovskite film. The bandgap of the perovskite is 1.5 eV.…”

Differentiated Functions of Potassium Interface Passivation and Doping on Charge-Carrier Dynamics in Perovskite Solar Cells

“…The decreased time constants indicate that electrons can be extracted effectively compared with those of the pristine sample. 40 As shown in Figure 2h, the trap density is estimated by the space-charge-limited-current (SCLC) technique with an electron-only FTO/SnO 2 (with or without a KI layer)/CsFAMA/PCBM/Ag structure. The trap densities (N t ) of perovskite films for the 0.1 M KIpassivated front-side interface and 3% KI-doped CsFAMA are 1.74 × 10 16 and 1.62 × 10 16 cm −3 , respectively, which are lower than that of the pristine one (3.22 × 10 16 cm −3 ).…”

“…τ 1 and τ 2 represent the time constants of the fast and slow decay processes, respectively, which are associated with extraction of charge from perovskite to ETL. The decreased time constants indicate that electrons can be extracted effectively compared with those of the pristine sample . As shown in Figure h, the trap density is estimated by the space-charge-limited-current (SCLC) technique with an electron-only FTO/SnO 2 (with or without a KI layer)/CsFAMA/PCBM/Ag structure.…”

Recent advances in the interfacial engineering of organic–inorganic hybrid perovskite solar cells: a materials perspective

“…Meanwhile, Al-doped CuS has been reported to be incorporated into inverted PSCs as an efficient inorganic HTL as well as an interfacial modification material, where the role of aluminum was mainly to modulate the energy-band matching of CuS and the perovskite. 171 This method not only optimizes the crystallization process of the perovskite by passivating the interfacial defects but can also be applied as a new HTL for inverted PSCs, rendering sulfide-based materials remarkably promising as HTL materials (Fig. 17i).…”