Stabilizing high-efficiency perovskite solar cells (PSCs) at operating conditions remains an unresolved issue hampering its large-scale commercial deployment. Here, we report a star-shaped polymer to improve charge transport and inhibit ion migration at the perovskite interface. The incorporation of multiple chemical anchor sites in the star-shaped polymer branches strongly controls the crystallization of perovskite film with lower trap density and higher carrier mobility and thus inhibits the nonradiative recombination and reduces the charge-transport loss. Consequently, the modified inverted PSCs show an optimal power conversion efficiency of 22.1% and a very high fill factor (FF) of 0.862, corresponding to 95.4% of the Shockley-Queisser limited FF (0.904) of PSCs with a 1.59-eV bandgap. The modified devices exhibit excellent long-term operational and thermal stability at the maximum power point for 1000 hours at 45°C under continuous one-sun illumination without any significant loss of efficiency.
Metal halide perovskites have attracted rapid development and great attention mainly due to its excellent optoelectronic properties. Currently, the efficiency of inverted (p-i-n) PSCs are around 23%, which catch up...
The performance enhancement of inverted perovskite solar cells applying nickel oxide (NiOx) as the hole transport layer (HTL) has been limited by impurity ions (such as nitrate ions). Herein, we have proposed a strategy to obtain high‐quality NiOx nanoparticles via an ionic liquid‐assisted synthesis method (NiOx‐IL). Experimental and theoretical results illustrate that the cation of the ionic liquid can inhibit the adsorption of impurity ions on nickel hydroxide through a strong hydrogen bond and low adsorption energy, thereby obtaining NiOx‐IL HTL with high conductivity and strong hole‐extraction ability. Importantly, the removal of impurity ions can effectively suppress the redox reaction between the NiOx film and the perovskite film, thus slowing down the deterioration of device performance. Consequently, the modified inverted device shows a striking efficiency exceeding 22.62 %, and superior stability maintaining 92 % efficiency at a maximum power point tracking under one sun illumination for 1000 h.
Although perovskite solar cells (PSCs) are on the road to industrialization, the operational stability under high efficiency still needs to be improved, and the water solubility of lead ions (Pb2+) will cause environmental pollution problems. Herein, it is successfully implanted an environment‐friendly (biodegradability) poly(butylene adipate‐coterephthalate) polymer (PBAT) into the perovskite film, which can passivate the uncoordinated Pb2+ and neutral iodine defects of the perovskite material because of the adequate carbonyl groups and benzene rings in PBAT polymer, thereby regulating the crystallization of perovskite film with lower trap density, inhibiting the nonradiative recombination and improving charge carrier transport. As a result, the polymer‐incorporated inverted PSCs achieve optimal conversion efficiencies of 22.07% (0.1 cm2) and 20.31% (1 cm2). Meanwhile, the incorporated device, after being encapsulated, exhibits a prominent improvement in operational stability of high‐efficiency device under maximum power point tracking and continuous one sunlight illumination, maintaining the initial efficiency of 80% for 3249 h. More importantly, the polymer network can protect Pb2+ from being dissolved by water and prevent nearly 98% of Pb2+ from leaking by directly immersing the polymer‐coated perovskite film in water. Environmental‐friendly molecules provide new hope for solving lead poisoning and improving device operational stability under high efficiency.
The competition between charge recombination and extraction principally affects the fill factor (FF) and power conversion efficiency (PCE) of planar thin-film solar cells. In Sb 2 S 3 thin-film solar cells, the electrocharge recombination and extraction n transport layer (ETL) plays a significant role in electron extraction and determination of Sb 2 S 3 film absorber quality. Herein, a TiO 2 ETL is strategically modified using an inorganic salt zinc halide (i.e., ZnCl 2 , ZnBr 2 , ZnI 2 ), which simultaneously improves the electronic properties of TiO 2 and promotes the growth of Sb 2 S 3 films with larger grain size and higher crystallinity. The experimental results and theoretical calculations further reveal that the zinc halide can interact with TiO 2 and simultaneously bond strongly with the upper Sb 2 S 3 film, which creates a unique pathway for electron transfer, passivates the trap states, and alleviates the recombination losses effectively. As a result, an average PCE of 6.87 ± 0.11% and the highest PCE of 7.08% have been attained with an improved FF from 51.22 to 61.61% after ZnCl 2 introduction. Additionally, introduction of ZnCl 2 helps the unencapsulated devices to maintain 93% of their original performance after 2400 h of storage in a nitrogen-filled glovebox. This work develops an effective route for the optimization of ETLs and defect healing using simple and low-cost inorganic salts.
Additive engineering is an effective strategy for defects passivation and performance improvement of perovskite solar cells (PSCs). However, few additives have achieved outstanding stability with high efficiency by simultaneously passivating...
Because of the compatibility with tandem devices and the ability to be manufactured at low temperatures, inverted perovskite solar cells have generated far‐ranging interest for potential commercial applications. However, their efficiency remains inadequate owing to various traps in the perovskite film and the restricted hole blocking ability of the electron transport layer. Thus, in this work, a wide‐bandgap n‐type semiconductor, 4,6‐bis(3,5‐di(pyridin‐4‐yl)phenyl)‐2‐phenylpyrimidine (B4PyPPM), to modify a perovskite film via an anti‐solvent method is introduced. The nitrogen sites of pyrimidine and pyridine rings in B4PyPPM exhibit strong interactions with the undercoordinated lead ions in the perovskite material. These interactions can reduce the trap state densities and inhibit nonradiative recombination of the perovskite bulk. Moreover, B4PyPPM can partially aggregate on the perovskite surface, leading to an improvement in the hole‐blocking ability at its interface. This modification can also increase the built‐in potential and upshift the Fermi level of the modified perovskite film, promoting electron extraction to the electron transport layer. The champion device achieves a high efficiency of 23.51%. Meantime, the sealed device retains ≈80% of its initial performance under a maximum power point tracking for nearly 2400 h, demonstrating an excellent operational stability.
Encapsulation engineering is an effective strategy to improve the stability of perovskite solar cells. However, current encapsulation materials are not suitable for lead-based devices because of their complex encapsulation processes, poor thermal management, and inefficient lead leakage suppression. In this work, we design a self-crosslinked fluorosilicone polymer gel, achieving nondestructive encapsulation at room temperature. Moreover, the proposed encapsulation strategy effectively promotes heat transfer and mitigates the potential impact of heat accumulation. As a result, the encapsulated devices maintain 98% of the normalized power conversion efficiency after 1000 h in the damp heat test and retain 95% of the normalized efficiency after 220 cycles in the thermal cycling test, satisfying the requirements of the International Electrotechnical Commission 61215 standard. The encapsulated devices also exhibit excellent lead leakage inhibition rates, 99% in the rain test and 98% in the immersion test, owing to excellent glass protection and strong coordination interaction. Our strategy provides a universal and integrated solution for achieving efficient, stable, and sustainable perovskite photovoltaics.
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