Non-Fullerene Acceptors Assisted Target Therapy for Interface Treatment Enable High Performance Inverted Perovskite Solar Cells.

Targeted treatment of the interface between electron transport layers (ETL) and perovskite layers is highly desirable for achieving passivating effects and suppressing carrier nonradiative recombination, leading to high performance and long-term stability in perovskite solar cells (PSCs). In this study, a series of non-fullerene acceptors (NFAs, Y-H, Y-F, and Y-Cl) are introduced to optimize the properties of the perovskite/ETL interface. This optimization involves passivating Pb2+ defects, releasing stress, and modulating carrier dynamics through interactions with the perovskite. Remarkably, after modifying with NFAs, the absorption range of perovskite films into the near-infrared region is extended. As expected, Y-F, with the largest electrostatic potential, facilitates the strongest interaction between the perovskite and its functional groups. Consequently, champion power conversion efficiencies of 21.17%, 22.21%, 23.25%, and 22.31% are achieved for control, Y-H-, Y-F-, and Y-Cl-based FA0.88Cs0.12PbI2.64Br0.36 (FACs) devices, respectively. This treatment also enhances the heat stability and air stability of the corresponding devices. Additionally, these modifier layers are applied to enhance the efficiency of Cs0.05(FA0.95MA0.05)0.95PbI2.64Br0.36 (FAMA) devices. Notably, a champion PCE exceeding 24% is achieved in the Y-F-based FAMA device. Therefore, this study provides a facile and effective approach to target the interface, thereby improving the efficiency and stability of PSCs.

Alkyl Chains Tune Molecular Orientations to Enable Dual Passivation in Inverted Perovskite Solar Cells.

Nonradiative recombination losses occurring at the interface pose a significant obstacle to achieve high-efficiency perovskite solar cells (PSCs), particularly in inverted PSCs. Passivating surface defects using molecules with different functional groups represents one of the key strategies for enhancing PSCs efficiency. However, a lack of insight into the passivation orientation of molecules on the surface is a challenge for rational molecular design. In this study, aminothiol hydrochlorides with different alkyl chains but identical electron-donating (-SH) and electron-withdrawing (-NH3 +) groups were employed to investigate the interplay between molecular structure, orientation, and interaction on perovskite surface. The 2-Aminoethane-1-thiol hydrochloride with shorter alkyl chains exhibited a preference of parallel orientations, which facilitating stronger interactions with the surface defects through strong coordination and hydrogen bonding. The resultant perovskite films following defect passivation demonstrate reduced ion migration, inhibition of nonradiative recombination, and more n-type characteristics for efficient electron transfer. Consequently, an impressive power conversion efficiency of 25 % was achieved, maintaining 95 % of its initial efficiency after 500 hours of continuous maximum power point tracking.

Multifunctional Trifluoroborate Additive for Simultaneous Carrier Dynamics Governance and Defects Passivation to Boost Efficiency and Stability of Inverted Perovskite Solar Cells.

The main obstacles to promoting the commercialization of perovskite solar cells (PSCs) include their record power conversion efficiency (PCE), which still remains below the Shockley-Queisser limit, and poor long-term stability, attributable to crystallographic defects in perovskite films and open-circuit voltage (Voc) loss in devices. In this study, potassium (4-tert-butoxycarbonylpiperazin-1-yl) methyl trifluoroborate (PTFBK) was employed as a multifunctional additive to target and modulate bulk perovskite defects and carrier dynamics of PSCs. Apart from simultaneously passivating anionic and cationic defects, PTFBK could also optimize the energy-level alignment of devices and weaken the interaction between carriers and longitudinal optical phonons, resulting in a carrier lifetime of greater than 3 µs. Furthermore, it inhibited non-radiative recombination and improved the crystallization capacity in the target perovskite film. Hence, the target rigid and flexible p-i-n PSCs yielded champion PCEs of 24.99 % and 23.48 %, respectively. More importantly, due to hydrogen bonding between formamidinium and fluorine, the target devices exhibited remarkable thermal, humidity, and operational tracking at maximum power point stabilities. The reduced Young's modulus and residual stress in the perovskite layer also provided excellent bending stability for flexible target devices.

Correction: Preventing lead leakage in perovskite solar cells and modules with a low-cost and stable chemisorption coating.

Correction for 'Preventing lead leakage in perovskite solar cells and modules with a low-cost and stable chemisorption coating' by Zongxu Zhang et al., Mater. Horiz., 2024, 11, 2449-2456, https://doi.org/10.1039/D4MH00033A.

Preventing lead leakage in perovskite solar cells and modules with a low-cost and stable chemisorption coating.

Despite the promising commercial prospects of perovskite solar cells, the issue of lead toxicity continues to hinder their future industrial applications. Here, we report a low-cost and rapidly degraded sulfosuccinic acid-modified polyvinyl alcohol (SMP) coating that prevents lead leakage and enhances device stability without compromising device performance. Even under different strict conditions (simulated heavy rain, acid rain, high temperatures, and competing ions), the coatings effectively prevent lead leakage by over 99%. After 75 days of outdoor exposure, the coating still demonstrates similar lead sequestration efficiency (SQE). In addition, it can be applied to different device structures (n-i-p and p-i-n) and modules, with over 99% SQE, making it a general method for preventing lead leakage.

Dynamic covalent polymer engineering for stable and self-healing perovskite solar cells.

Perovskite films are susceptible to degradation during their service period due to their weak mechanical properties. Acylhydrazone-bonded waterborne polyurethane (Ab-WPU) was employed as dynamic covalent polymer engineering to develop self-healing perovskite solar cells (SHPSCs). Ab-WPU enhances the crystallinity of the perovskite film, passivates the defects of the perovskite film through functional groups, and demonstrates promising flexibility and mild temperature self-healing properties of SHPSCs. The champion efficiency of SHPSCs on rigid and flexible substrates reaches 24.2% and 21.27% respectively. The moisture and heat stability of devices were improved. After 1000 bending cycles, the Ab-WPU-modified flexible device can be restored to an efficiency of over 95% of its original efficiency by heating to 60 °C. This is because the dynamic acylhydrazone bond can be activated to repair perovskite film defects at a mild temperature of 60 °C as evidenced by in situ AFM studies. This strategy provides an effective pathway for dynamic self-healing materials in PSCs under operational conditions.