Dawen Li

Perovskite solar cells achieve high power conversion efficiencies and are compatible with scalable, low-cost manufacturing, but their commercialization is limited by insufficient operational stability. Conventional stability tests usually rely on static protocols, such as continuous illumination or elevated temperature aging, which could fail to capture real-world degradation pathways. Mechanical stress and strain contribute to defect formation, ion migration, cracking, and delamination but are often reported only as static residual states established during fabrication. This review emphasizes the need to consider how stress and strain evolve under realistic conditions involving fluctuating temperature, illumination, and humidity. Temperature cycling induces thermal expansion mismatch stress, illumination drives lattice expansion and phase segregation, and moisture-induced degradation is coupled to stress and strain. Buried interface engineering and polymer incorporation in the perovskite absorber are highlighted as strategies to actively mitigate transient stress fluctuations, allowing for the design of mechanically robust perovskite photovoltaics suitable for real-world deployment.

Due to the presence of numerous defects in polycrystalline perovskite films, the performance of the target devices is limited. This work suggests using the –NH3+ produced during the protonation of cyclohexylamine hydrochloride (CHLCl) to passivate perovskite film interface flaws and improve device performance. The device interfacial defects are passivated by hydrogen bonding between the functional groups of the passivants and uncoordinated ions in the films. Meanwhile, the cyclohexylamine hydrochloride layer results in a smoother perovskite surface, which facilitates the charge transport in the devices. The modified device obtained a champion power conversion efficiency (PCE) of 21.53%, which is 11.21% higher than that of the control device (19.36%). The modified device preserved 80% of initial PCE after 720 h, compared to 58% for the control device. Dynamic simulations and DFT calculations revealed that CHLCl exhibits enhanced interfacial migration behavior and moderate adsorption energy, enabling effective defect passivation and improved interfacial charge transport. It establishes a common design paradigm for efficient and low-cost perovskite materials.

Perovskite solar cells (PSCs) have emerged as a rising next-generational photovoltaic technology due to low fabrication costs through solution processing as compared to traditional silicon solar cells and high-power conversion efficiency. However, the poor long-term operational stability due to environmental and mechanical degradation remains a hindrance to commercialization. Herein, self-healing polymer additives are utilized by researchers to enhance the photovoltaic performance of PSCs by enabling self-restorative behavior from physical damage or chemical degradation. This review explores the design and application of self-healing polymers in both flexible and rigid PSCs, contrasting the two main reversible bonding mechanisms: physical bonds, such as hydrogen bonds, and chemical bonds, such as dynamic covalent disulfide bonds. Physical bonds provide passive healing at ambient conditions; meanwhile, chemical bonds offer a stronger restoration under external stimuli such as heat or light. These polymers are exceptionally effective at mitigating mechanical stress and cracks in flexible PSCs and combating moisture-induced degradation in rigid PSCs. The applications of self-healing polymers are categorized based on substrate type, healing mechanism, and perovskite composition, with the benefits and limitations of each approach highlighted. Additionally, the review explores the potential of multifunctional self-healing polymers to passivate defects at the grain boundaries and on surface of perovskite films, thereby enhancing the overall photovoltaic performance.

Perovskite solar cells (PSCs) have gained significant attention due to their impressive power conversion efficiencies. However, developing rapid fabrication techniques for commercially feasible production of PSCs with high stability and efficiency requires more investigation. Also, as a feasible approach, additive strategy plays a crucial role in enhancing crystallinity and reducing defects of perovskite films, thereby improving the device performance. Herein, we explored the synergy of rapid UV‐LED annealing of multiple stacked layers while incorporating chlorine‐containing additive to enhance the morphology, crystallinity, and optoelectronic properties of perovskite absorber and demonstrated significant improvement of overall PSC performance, including both efficiency and stability. Specifically, chlorine incorporation leads to larger grain sizes, reduced defects and recombinations, and more efficient perovskite conversion with rapid UV‐LED annealing. The best all‐rapid photonic annealed (all‐RPA) PSC device with addition of chlorine‐containing additive demonstrates a PCE of 21.7% and retains over 80% of the initial PCE after 1000 h, which is the highest PCE ever reported on traditional MAPbI ₃ ‐based PSCs fabricated with all kinds of optical annealing schemes. This work sheds light on the role of synergistic effects of UVA‐LED annealing and chlorine incorporation and paves the way for large‐scale manufacturing of perovskite‐based photovoltaics by using rapid and energy‐efficient UV‐LED photonic annealing.

This study focuses on optimizing direct current, reactively sputtered nickel oxide (NiOx) as a hole transport layer (HTL) for perovskite solar cells (PSCs). By employing reactively sputtered NiOx instead of spin-coated NiOx, the redox reaction between the HTL and the perovskite layer in PSCs was minimized. Additionally, the study examines the impact of different annealing conditions on the oxidation state of NiOx HTL and its effect on PSC performance. X-ray diffraction analysis revealed that a higher oxygen flow rate and lower deposition rate resulted in a more continuous film with enhanced crystallinity. X-ray photoelectron spectroscopy further indicated that Ni2+ ion concentration increased with atmospheric and high-temperature annealing. By systematically optimizing sputtering parameters and annealing conditions, the power conversion efficiency of PSCs was significantly improved from 5% to 13.5%, highlighting the importance of controlling the oxidation state of NiOx HTL to enhance PSC performance.

Both high-power conversion efficiency (PCE) and long-term stability are critical needs for a reliable perovskite solar cell (PSC). In this work, a polyamidoamine (PAMAM) dendrimer is employed to enhance the efficiency and stability of double-cation-based PSCs via different fabrication scenarios. Based on our experimental results and numerical analysis, the application of a thin layer of PAMAM macromolecules at the interface of the perovskite absorber and the hole transport layer gives rise to enhanced performance, including both efficiency and stability due to reduced interface defects and lower carrier recombination. The results suggest that PAMAM as a capping layer can effectively passivate the surface defects of the perovskite film. As a result, a PCE of 22.8% has been achieved, while the reference devices without the PAMAM passivation layer exhibit a PCE of 20.9%. The operational stability at maximum power point (MPP) under continuous 1 sun illumination and dark storage stability show that the target perovskite/PAMAM device retains 80% of its initial PCE after 1000 h. Our research could significantly impact the field by providing valuable insights into surface passivation using macromolecules to improve the performance of perovskite-based photovoltaic devices.