The progress of photovoltaic performance is hampered by photon and carrier losses in the electron transport layer (ETL) of conventional n-i-p perovskite solar cells (PSCs). Herein, we propose a simple and effective approach to reduce photon and carrier losses. The multisite chiral molecule L-histidine hydrochloride monohydrate (LHHM) is employed to manipulate SnO2 ETL. The LHHM can not only inhibit the agglomeration of SnO2 nanoparticles but also effectively passivate oxygen vacancy and/or uncoordinated Sn4+ defects by multiple active sites and multiple chemical bonds, which is translated into increased light transmittance and enhanced electron mobility, minimizing photon and carrier losses in ETL. Moreover, the bottom-up defect passivation is realized by LHHM modification. The LHHM incorporation also improves interfacial energy band alignment, facilitates perovskite crystallization and releases tensile stress, which minimizes bulk and interfacial nonradiative recombination. The target device demonstrates a power conversion efficiency (PCE) of 25.06%. This is one of the highest PCEs for devices made in ambient air that has ever been documented. Furthermore, after 1000hours of aging at 65 °C, under one sun's irradiation, and under 20-25% relative humidity, the unencapsulated target devices retain 94%, 81%, and 88% of their initial PCEs.

The defects from functional layers and interface, the agglomeration of SnO2 nanoparticles (NPs), and poor perovskite crystallization are the main barrier to further heightening the power conversion efficiency (PCE) and stability of regular perovskite solar cells. Here, a bottom-up multilayer manipulation strategy by pre-embedding multisite racemic DL-cysteine hydrochloride monohydrate (DLCH) into the SnO2 electron transport layer (ETL) is reported. The positively and negatively charged defects from ETL, perovskite layer and their interface can be passivated through the synergistic effect of the SH, COOH, NH3+, and Cl- groups in DLCH. The synergy of multiple functional groups and multiple chemical bonds enables bottom-up cross-layer passivation, which minimizes bulk and interfacial nonradiative recombination losses. Furthermore, the multifunctional DLCH plays a role in inhibiting the agglomeration of SnO2 NPs, managing photons, relieving interfacial tensile stress, and manipulating perovskite crystallization. Benefiting from the above advantages, the DLCH-incorporating device delivers a PCE of 24.01%, which is much higher than the 21.61% of the control device. Moreover, the DLCH-modified devices demonstrate inviting thermal and ambient stabilities by maintaining 93% of the initial efficiency after aging at 65 degrees C for 1800 h and 95% of the original PCE after aging under a relative humidity of 20-25% for 2000 h. A bottom-up multilayer manipulation strategy is proposed by pre-embedding multisite racemic DL-cysteine hydrochloride monohydrate (DLCH) into SnO2 electron transport layer. The synergy of multiple functional groups and multiple chemical bonds enables bottom-up cross-layer passivation, which minimizes bulk and interfacial nonradiative recombination losses. The power conversion efficiency is improved from 21.61 to 24.01% after DLCH modulation.image

The instability of top interface induced by interfacial defects and residual tensile strain hinders the realization of long-term stable n-i-p regular perovskite solar cells (PSCs). Herein, one molecular locking strategy is reported to stabilize top interface by adopting polydentate ligand green biomaterial 2-deoxy-2,2-difluoro-d-erythro-pentafuranous-1-ulose-3,5-dibenzoate (DDPUD) to manipulate the surface and grain boundaries of perovskite films. Both experimental and theoretical evidence collectively uncover that the uncoordinated Pb2+ ions, halide vacancy, and/or I─Pb antisite defects can be effectively healed and locked by firm chemical anchoring on the surface of perovskite films. The ingenious polydentate ligand chelating is translated into reduced interfacial defects, increased carrier lifetimes, released interfacial stress, and enhanced moisture resistance, which should be liable for strengthened top interface stability and inhibited interfacial nonradiative recombination. The universality of the molecular locking strategy is certified by employing different perovskite compositions. The DDPUD modification achieves an enhanced power conversion efficiency (PCE) of 23.17-24.47%, which is one of the highest PCEs ever reported for the devices prepared in ambient air. The unsealed DDPUD-modified devices maintain 98.18% and 88.10% of their initial PCEs after more than 3000 h under a relative humidity of 10-20% and after 1728 h at 65 °C, respectively.

The instability of the buried interface poses a serious challenge for commercializing perovskite photovoltaic technology. Herein, we report a polydentate ligand reinforced chelating strategy to strengthen the stability of buried interface by managing interfacial defects and stress. The bis(2,2,2-trifluoroethyl) (methoxycarbonylmethyl)phosphonate (BTP) is employed to manipulate the buried interface. The C=O, P=O and two −CF 3 functional groups in BTP synergistically passivate the defects from the surface of SnO 2 and the bottom surface of the perovskite layer. Moreover, The BTP modification contributes to mitigated interfacial residual tensile stress, promoted perovskite crystallization, and reduced interfacial energy barrier. The multidentate ligand modulation strategy is appropriate for different perovskite compositions. Due to much reduced nonradiative recombination and heightened interface contact, the device with BTP yields a promising power conversion efficiency (PCE) of 24.63 %, which is one of the highest efficiencies ever reported for devices fabricated in the air environment. The unencapsulated BTP-modified devices degrade to 98.6 % and 84.2 % of their initial PCE values after over 3000 h of aging in the ambient environment and after 1728 h of thermal stress, respectively. This work provides insights into strengthening the stability of the buried interface by engineering multidentate chelating ligand molecules.

Perovskite solar cells (PSCs) have obtained great triumph in photovoltaic technologies due to their excellent optoelectronic properties. In particular, the use of one-dimensional (1D) materials including 1D perovskites (defined according to crystal structures) and 1D carrier transport materials (defined according to morphology) has been widely demonstrated to be able to effectively enhance the power conversion efficiency (PCE) and stability of PSCs because of their some unique properties. In view of the huge contributions of 1D materials in PSCs, a comprehensive understanding of 1D materials in PSCs is necessary. In this review, we first introduce the structure, properties, and synthesis of 1D perovskites. Then, we discuss the recent development of PSCs based on 1D/3D perovskite heterojunctions including bulk 1D/3D perovskite heterojunctions and interfacial 1D/3D perovskite heterojunctions. Subsequently, we discuss the 1D carrier transport layers. Finally, we give a plausible conclusion and outlook of 1D materials in PSCs which can further facilitate the advancement of PSCs. Illustration of the position and functions of 1D materials in PSCs.

Passivating the defective surface of perovskite film is a promising strategy to improve the stability and efficiency of perovskite solar cells (PSCs). Herein, 1-adamantanamine hydrochloride (ATH) is introduced to the upper surface of the perovskite film to heal the defects of the perovskite surface. The best-performance ATH-modified device has a higher efficiency (23.45%) than the champion control device (21.53%). The defects are passivated, interfacial nonradiative recombination is suppressed, and interface stress is released by the ATH deposited on the perovskite film, leading to longer carrier lifetimes and enhancement in open-circuit voltage (VOC) and fill factor (FF) of the PSCs. With obvious improvement, VOC and FF of 1.159 V and 0.796 for the control device are raised to 1.178 V and 0.826 for the ATH-modified device, respectively. Finally, during an operational stability measurement of more than 1000 h, the ATH-treated PSC exhibited better moisture resistance, thermal persistence, and light stability.

在储能型模块化多电平换流器(MMC)中,电池模块的差异性导致各电池模块荷电状态(SOC)不一致.为了提高电池容量利用率,需要对各电池模块的SOC均衡控制.介绍了储能型MMC的结构与原理,分析了分别基于交流功率与直流功率的三级SOC均衡方法,并对各级均衡方法进行了评估,得到了相间、上下桥臂间、桥臂内各模块间的电池SOC均衡策略,结合功率解耦控制与差分电流控制提出了系统整体控制策略.最后,搭建实验样机验证了所提均衡策略的可行性.