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The photovoltaic performance of perovskite solar cells (PSCs) prepared by the low‐temperature solution method has made rapid progress. However, the surface of the film is prone to defects that trap photogenerated charges, resulting in nonradiative recombination energy loss and limiting the open‐circuit voltage and overall performance of the device. Interface passivation as an effective method can significantly reduce defects and inhibit nonradiative recombination. Herein, a simple method is introduced to passivate perovskite films by a carboxylated (–COOH) sensitizer that is applied in dye‐sensitized solar cells (DSCs), 4‐(bis(9,9‐dimethyl‐9H‐flouren‐2‐yl)amino)‐1‐naphthoic acid (KTN) molecules. The research results show that the chemical interaction between KTN and iodide vacancies exposing Pb2+ can reduce the nonradiative recombination and elongate the carrier lifetime, which leads to an excellent power conversion efficiency (PCE) with 23% with an obvious increase in open‐circuit voltage (VOC) of 60 mV. Moreover, the defect passivation can significantly enhance the stability of corresponding PSC devices. The unencapsulated device with KTN passivation can readily maintain ≈90% of its initial efficiency value after 1400 h. These findings may provide a novel approach for interfacial defect passivation to further promote the performance and stability of PSCs. [ABSTRACT FROM AUTHOR]

Doping in organic–inorganic perovskite semiconductors is an effective method to tailor their optoelectronic properties. In this work, manganese-doped perovskite films with different Mn/Pb ratios ranging from 0% to 2% were systematically studied. The device performance of 0.2% Mn-doped devices was improved compared to that of a device without Mn. However, a further increase of the doping concentration induced a decrease in performance. Several characteristics (especially different scanning probe microscopy characteristics) reveal that an increased dopant concentration results in reduced crystallinity and a change in the film morphology and causes a deterioration in photovoltaic performance for higher dopant concentrations. In the best-performing samples (0.2%), a shift in the valence band level and band gap are found which are responsible for the increased open circuit voltage, while increased grain boundaries and lower surface charge density are responsible for a small reduction in the short circuit current. Thus, multifunctional scanning probe microscopy approaches, combined with different film characterization techniques, offer us effective tools to investigate the impact of doping in the perovskite materials and the corresponding device performance. • Scanning Kelvin Probe Microscopy is used to test the open circuit voltage of films. • Conductive atomic force microscopy is used to study the short-circuit of films. • Electrostatic force microscopy is used to distinguish the surface charge change of films. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are the most promising substitute for silicon-based solar cells. However, their power conversion efficiency and stability must be improved. The recombination probability of the photogenerated carriers at each interface in a PSC is much greater than that of the bulk phase. The interface of a perovskite polycrystalline film is considered to be a defect-rich area, which is the main factor limiting the efficiency of a PSC. This review introduces and summarizes practical interface engineering techniques for improving the efficiency and stability of organic–inorganic lead halide PSCs. First, the effect of defects at the interface of the PSCs, the energy level alignment, and the chemical reactions on the efficiency of a PSC are summarized. Subsequently, the latest developments pertaining to a modification of the perovskite layers with different materials are discussed. Finally, the prospect of achieving an efficient PSC with long-term stability through the use of interface engineering is presented. [ABSTRACT FROM AUTHOR]

Although a compact holes-transport-layer (HTL) film has always been deemed mandatory for perovskite solar cells (PSCs), the impact their compactness on the device performance has rarely been studied in detail. In this work, based on a device structure of FTO/CIGS/perovskite/PCBM/ZrAcac/Ag, that effect was systematically investigated with respect to device performance along with photo-physics characterization tools. Depending on spin-coating speed, the grain size and coverage ratio of those CIGS films on FTO substrates can be tuned, and this can result in different hole transfer efficiencies at the anode interface. At a speed of 4000 r.p.m., the band level offset between the perovskite and CIGS modified FTO was reduced to a minimum of 0.02 eV, leading to the best device performance, with conversion efficiency of 15.16% and open-circuit voltage of 1.04 V, along with the suppression of hysteresis. We believe that the balance of grain size and coverage ratio of CIGS interlayers can be tuned to an optimal point in the competition between carrier transport and recombination at the interface based on the proposed mechanism. This paper definitely deepens our understanding of the hole transfer mechanism at the interface of PSC devices, and facilitates future design of high-performance devices. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have been intensively investigated over the last several years. Unprecedented progress has been made in improving their power conversion efficiency; however, the stability of perovskite materials and devices remains a major obstacle for the future commercialization of PSCs. In this review, recent progress in PSCs is summarized in terms of the hybridization of compositions and device architectures for PSCs, with special attention paid to device stability. A brief history of the development of PSCs is given, and their chemical structures, optoelectronic properties, and the different types of device architectures are discussed. Then, perovskite composition engineering is reviewed in detail, with particular emphasis on the cationic components and their impact on film morphology, the optoelectronic properties, device performance, and stability. In addition, the impact of two-dimensional and/or one-dimensional and nanostructured perovskites on structural and device stability is surveyed. Finally, a future outlook is proposed for potential resolutions to overcome the current issues. [ABSTRACT FROM AUTHOR]