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The self‐assembled hole transporting molecules (SAHTMs) bearing anchoring groups have been established as the hole transporting layers (HTLs) for highly efficient p–i–n perovskite solar cells (PSCs), yet their stability and engineering at the molecular level remain challenging. A topological design of highly anisotropic aligned SAHTM‐based HTLs for operationally stable PSCs that exhibit exceptional solar‐to‐electric power conversion efficiencies (PCEs) is demonstrated. The judiciously designed multifunctional self‐assembled molecules comprise the donor–acceptor subunit for hole transporting and the phosphonic acid group for anchoring, realizing face‐on π‐stacking parallel to the transparent conductive oxide substrate. The high affinity of SAHTMs to the multi‐crystalline perovskite thin film benefits passivating the perovskite buried interface, strengthening interfacial contact while facilitating interfacial hole transfer. Consequently, highly efficient p–i–n PSC devices are obtained with a champion PCE of 23.24% and outstanding operational stability toward various environmental factors including long‐term full sunlight soaking at evaluated temperatures. Perovskite solar modules with a champion efficiency approaching 20% are also fabricated for an active device area above 17 cm2. [ABSTRACT FROM AUTHOR]

Long‐term stability has become the major obstacle for the successful large‐scale application of perovskites devices. Owing to the ionic nature of metal‐halide perovskites, the interfacial ion diffusion can induce irreversible degradation under operational conditions, which presents a great challenge to realize stable perovskite solar modules. Here, a diphenylphosphine oxide compound, ethane‐1,2‐diylbis(diphenylphosphine oxide) (DPPO) is introduced to coordinate with lead iodide and form a cross‐linked 1D Pb3I6‐DPPO (1D‐PbI2) complex. These judiciously designed cross‐linked nonionic low‐dimensional lead halide/organic adducts can passivate the defects of perovskite while acting as a robust ion diffusion barrier, thus significantly improving the electronic quality and intrinsic stability of perovskite films. As a result, high‐performance inverted (p‐i‐n) solar modules with a champion efficiency approaching 19% (a certified stabilized efficiency of 17.8%) for active device areas above 17 cm2 without the use of antisolvents, accompanied by outstanding operational stability under heat stress and continuous illumination are achieved. [ABSTRACT FROM AUTHOR]

Reaching the full potential of solar cells based on photo‐absorbers of organic‐inorganic hybrid perovskites requires highly efficient charge extraction at the interface between perovskite and charge transporting layer. This demand is generally challenged by the presence of under‐coordinated metal or halogen ions, causing surface charge trapping and resultant recombination losses. These problems can be tackled by introducing a small molecule interfacial anchor layer based on dimethylbiguanide (DMBG). Benefitting from interactions between the nitrogen‐containing functional groups in DMBG and unsaturated ions in CH3NH3PbI3 perovskites, the electron extraction of TiO2 is dramatically improved in association with reduced Schottky–Read–Hall recombination, as revealed by photoluminescence spectroscopy. As a consequence, the power conversion efficiency of CH3NH3PbI3 solar cells is boosted from 17.14 to 19.1 %, showing appreciably reduced hysteresis. The demonstrated molecular strategy based on DMBG enables one to achieve meliorations on key figures of merit in halide perovskite solar cells with improved stability. Surface traps: Incorporating a dimethylbiguanide (DMBG) anchoring layer in between the compact TiO2 and perovskite photo‐absorber leads to an effective passivation of surface traps with reduced Shockley–Read–Hall recombination, such that the power conversion efficiency of CH3NH3PbI3 solar cells is boosted to 19.1 %. [ABSTRACT FROM AUTHOR]

To reduce intrinsic defect density in perovskite films, various additives are often added into the precursor solution. In this paper, a novel solution, in which isopropanol (IPA) was added into the precursor solution, was developed for the preparation of normal planar perovskite solar cells (PSCs). A champion power conversion efficiency (PCE) of 19.70 % was achieved with this approach. By adding IPA into the precursor solution, CH3NH3PbI3 perovskite showed better crystallization and stability, indicating improved film quality. Because of the improved morphology of perovskite crystal, the PCE of PSCs increased. In addition, the unencapsulated PSCs retained high output for up to 40 days in air at room temperature, indicating the stability of PSCs. These results may provide a new avenue for manufacturing high efficiency and high stability PSCs. [ABSTRACT FROM AUTHOR]

TEC induced on the top of PCBM have been studied as the cathode-interfacial layer (CIL) and the CIL/perovskite interface is modified with a well-matched energy band alignment and suppressed defects. Enhanced power conversion efficiency with negligible hysteresis is obtained for planar perovskite solar cells. • A seamless PCBM@TEC capped perovskite film for the inverted planar PSCs. • PCBM@TEC CIL induced obvious efficiency enhancement for inverted PSCs. • Non-encapsulated devices based on the hydrophobic PCBM@TEC CIL improved stability of planar PSCs. • These improvements in performance and stability highlight the merit of using PCBM@TEC as interfacial layer in planar PSCs. Among the factors that lead to the reduction of the efficiency and stability of perovskite solar cells (PSCs) using [6,6]-phenyl C61 butyric acid methyl ester (PCBM) versus those of conventional structure, is the difficulty involved in realizing a high-quality film, and the non-radiative recombination that takes place at the interface between PCBM and perovskite. Our present work proposes a fabrication technique capable of overcoming these issues. Organic small molecule material was introduced along with PCBM, to obtain a homogeneously seamless film that plays the role of a dipole layer. The incorporated triethyl citrate (TEC) boosts the power conversion efficiency (PCE) from 14.56% to 17.86% with suppressed hysteresis, which originates primarily from the efficient electron transfer between the perovskite/PCBM and the Ag cathode interface. The results of electrochemical impedance spectroscopy measurements imply efficient electron transfer, low series resistance, and large recombination resistance in the photovoltaic device employing PCBM@TEC as the cathode interfacial layer. Specifically, the highly hydrophobic PCBM@TEC cathode interfacial layer (CIL) showed higher resistance to moisture, leading to a more environmentally-stable device. The results also showed the efficiency of the device retained 84% of its initial value after 30 days of operation under ambient conditions, which shows a visibly superior stability compared to a reference device that, under the same environment, retained only 37% its initial efficiency. Such advancement in the operational efficiency and stability of the device, will contribute to the longevity and cost-effectiveness of inverted PSC devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • PNCs-radical core/shell structure was prepared by P -type organic radical polymer. • This structure improves the stability of PNCs with charge transfer processes. • The stable PNCs-radical core/shell complex demonstrate superb reduction ability. • This strategy could promote the performance of PNCs based n-i-p solar cells. Balancing the stability and interfacial charge transfer (CT) ability of perovskite nanocrystals (PNCs) are the most challenging issue confronting their practical application in photoelectrochemistry (PEC) fields. Here, an efficient surface capping strategy is introduced relying on a set of air-stable nitroxide-based organic radical polymers with well-matched energy levels towards CsPbBr 3 nanocrystals. The native ligand oleyl amine and oleic acid were readily replaced by radical polymers because of their high-affinity properties. The resulting radical polymer coated PNCs exhibit exceptional tolerance to water, thermal, and UV illumination with remarkable CT processes. The versatility and immense practical utility of such stable PNCs-radical core/shell structure are showcased by the halogen exchange between PNCs/radical and aryl chlorides at ambient temperature, demonstrating superb reduction ability of this complex. Besides, this strategy was also employed to improve the power conversion efficiency and stability of PNCs based solar cells. This approach imparts exceptional photoelectrochemical stability and catalytic activity to the nanocrystals with excellent interfacial CT efficiency. [ABSTRACT FROM AUTHOR]