Long-term stability remains a key issue impeding the commercialization of halide perovskite solar cells (HPVKSCs). The diffusion of molecules and ions causes irreversible degradation to photovoltaic device performance. Here, we demonstrate a facile strategy for producing highly stable HPVKSCs by using a thin but compact semimetal Bismuth interlayer. The Bismuth film acts as a robust permeation barrier that both insulates the perovskite from intrusion by undesirable external moisture and protects the metal electrode from iodine corrosion. The Bismuth-interlayer-based devices exhibit greatly improved stability when subjected to humidity, thermal and light stresses. The unencapsulated device retains 88% of its initial efficiency in ambient air in the dark for over 6000 h; the devices maintain 95% and 97% of their initial efficiencies after 85 °C thermal aging and light soaking in nitrogen atmosphere for 500 h, respectively. These sound stability parameters are among the best for planar structured HPVKSCs reported to date.

Organic light emitting diodes (OLEDs) employing organic thin‐film based emitters have attracted tremendous attention due to their widespread applications in lighting and as displays in mobile devices and televisions. The novel thin‐film photovoltaic techniques using organic or organic–inorganic hybrid materials such as organic photovoltaics (OPVs) and perovskite solar cells (PSCs) have become emerging competitive candidates with regard to the traditional photovoltaic techniques on account of high‐efficiency, low‐cost, and simple manufacturing processing properties. However, OLEDs, OPVs, and PSCs are vulnerable to the undesired degradation induced by moisture and oxygen. To afford long‐term stability, a robust encapsulation technique by employing materials and structures that possess high barrier performance against oxygen and moisture must be explored and employed to protect these devices. Herein, the recent progress on specific encapsulation materials and techniques for three types of devices on the basis of fundamental understanding of device stability is reviewed. First, their degradation mechanisms, as well as, influencing factors are discussed. Then, the encapsulation technologies and materials are classified and discussed. Moreover, the advantages and disadvantages of various encapsulation technologies and materials coupled with their encapsulation applications in different devices are compared. Finally, the ongoing challenges and future perspectives of encapsulation frontier are provided.

Nowadays, the integrated systems on a plane substrate containing energy harvesting, energy storing, and working units are strongly desired with the fast development of wearable and portable devices. Here, a simple, low cost, and scalable strategy involving ink printing and electrochemical deposition is proposed to fabricate a flexible integrated system on a plane substrate containing an all-solid-state asymmetric microsupercapacitor (MSC), a photoconduct-type photodetector of perovskite nanowires (NWs), and a wireless charging coil. In the asymmetric MSCs, MnO-PPy and VO-PANI composites are used as positive and negative electrodes, respectively. Typical values of energy density in the range of 15-20 mWh cm at power densities of 0.3-2.5 W cm with an operation potential window of 1.6 V are achieved. In the system, the wireless charging coil receives energy from a wireless power transmitter, which then can be stored in the MSC to drive the photoconductive detector of perovskite NWs in sequence. The designed integrated system exhibits a stable photocurrent response comparable with the detector driven by an external power source. This research provides an important routine to fabricate integrated systems.

Exceptionally high efficiencies for organic–inorganic hybrid perovskite solar cells (PSCs) have been achieved. However, their operational stability still needs to be improved. The intrinsic instability of halide perovskites caused by the presence of volatile organic cations, as well as the degradation of hybrid perovskites induced by the adverse permeation of environmental water (H2O)/oxygen (O2) and the undesired ion diffusion or migration are the major reasons. Beyond strengthening perovskites themselves, interface engineering is now regarded as a valid strategy to prolong device lifetime by preventing the undesired degradation pathways. This comprehensive review highlights the utilization of practical interface engineering for enhancing the efficiency and stability of organic–inorganic lead halide PSCs. First, the impacts of interface design on the energy‐level alignment and carrier dynamics are overviewed. Second, recent progresses on the development of interfacial materials for simultaneously achieving high efficiency and stability of PSCs are summarized. At last, the interfacial layer design principles along with future outlook of this rapidly developing field are discussed.

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Perovskite solar cells (PSCs) have attracted much attention in the past decade and their power conversion efficiency has been rapidly increasing to 25.2%, which is comparable with commercialized solar cells. Currently, the long‐term stability of PSCs remains as a major bottleneck impeding their future commercial applications. Beyond strengthening the perovskite layer itself and developing robust external device encapsulation/packaging technology, integration of effective barriers into PSCs has been recognized to be of equal importance to improve the whole device’s long‐term stability. These barriers can not only shield the critical perovskite layer and other functional layers from external detrimental factors such as heat, light, and H2O/O2, but also prevent the undesired ion/molecular diffusion/volatilization from perovskite. In addition, some delicate barrier designs can simultaneously improve the efficiency and stability. In this review article, the research progress on barrier designs in PSCs for improving their long‐term stability is reviewed in terms of the barrier functions, locations in PSCs, and material characteristics. Regarding specific barriers, their preparation methods, chemical/photoelectronic/mechanical properties, and their role in device stability, are further discussed. On the basis of these accumulative efforts, predictions for the further development of effective barriers in PSCs are provided at the end of this review.

Perovskite solar cells have emerged as one of the most promising thin-film photovoltaic (PV) technologies and have made a strong debut in the PV field. However, they still face difficulties with up-scaling to module-level devices and long-term stability issue. Here, we report the use of a room-temperature nonvolatile Lewis base additive, diphenyl sulfoxide(DPSO), in formamidinium-cesium (FACs) perovskite precursor solution to enhance the nucleation barrier and stabilize the wet precursor film for the scalable fabrication of uniform, large-area FACs perovskite films. With a parallel-interconnected module design, the resultant solar module realized a certified quasi-stabilized efficiency of 16.63% with an active area of 20.77 cm2. The encapsulated modules maintained 97 and 95% of their initial efficiencies after 10,000 and 1187 hours under day/night cycling and 1-sun equivalent white-light light-emitting diode array illumination with maximum power point tracking at 50°C, respectively.