Inorganic halide perovskite solar cells (IHPSCs) have become one of the most promising research hotspots due to to the excellent light and thermal stabilities of inorganic halide perovskites (IHPs). Despite rapid progress in cell performance in very recent years, the phase instability of IHPs easily occurs, which will remarkably influence the cell efficiency and stability. Much effort has been devoted to solving this issue. In this review, we focus on representative progress in the stability from IHPs to IHPSCs, including (i) a brief introduction of inorganic perovskite materials and devices, (ii) some new additives and fabrication methods, (iii) thermal and light stabilities, (iv) tailoring phase stability, (v) optimization of the stability of inorganic perovskite solar cells and (vi) interfacial engineering for stability enhancement. Finally, perspectives will be given regarding future work on highly efficient and stable IHPSCs. This review aims to provide a thorough understanding of the key influential factors on the stability of materials to highly efficient and stable IHPSCs.

Organic solar cells (OSCs) have reached an outstanding certified power conversion efficiency (PCE) of over 19% in single junction and 20% in tandem architecture design. Such high PCEs have emerged with outstanding Y-shaped Y6 non-fullerene acceptors (NFAs), together with PM6 electron donor polymers. PCEs are on the rise for small-area OSCs. However, large-area OSC sub-modules are still unable to achieve such high PCEs, and the highest certified PCE reported so far is ∼12% having an area of 58 cm₂. To fabricate efficient large-area OSCs, new custom-designed NFAs for large-area systems are imminent along with improvements in the sub-module fabrication platforms. Moreover, the search for stable yet efficient OSCs is still in progress. In this review, progress in small-area OSCs is presented with reference to the advancement in the chemical structure of NFAs and donor polymers. Finally, the life-cycle assessment of OSCs is presented and the energy payback time of the efficient and stable OSCs is discussed and lastly, an outlook for the OSCs is given.

Towards commercialization of perovskite solar cells (PSCs), further reducing the cost and increasing the stability of PSCs have been the most important tasks of researchers, as the efficiency of single-junction PSCs has reached a competitive level among all kinds of single-junction solar cells. Carbon-electrode-based PSCs (CPSCs), as one of the most promising constructions for achieving stable economical PSCs, now attract enormous attention for their cost-effectiveness and stability. Here, we briefly review the development of CPSCs and reveal the importance of n-i-p architecture for state-of-the-art CPSCs. However, despite their promising potential, challenges still exist in CPSCs in the n-i-p architecture, which mainly stem from the incompact contact of the hole-transporting layer (HTL)/carbon electrode. Thus, new carbon materials and/or novel manufacturing methods should be proposed. In addition, HTL is yet to be appropriate for state-of-the-art CPSCs because the fabrication of carbon electrode could result in the destruction of the underlayer. To further enhance the performance of CPSCs, both the HTL and electron transport layer as well as their interfaces with perovskite active layer need to be improved. We recommend that the perovskite active layer, with its long carrier lifetime, strong carrier transport capability, and long-term stability, is necessary as well for improved performance of CPSCs. We also highlight current researches on CPSCs and provide a systematic review of various types of regulation tools.

In recent years, two-dimensional metal halide perovskites (MHPs) have attracted increased attention for radiation detection and imaging. Their detection efficiencies are almost comparable to three-dimensional (3D) perovskites. Meanwhile, they demonstrate superior stability to 3D perovskites. The pursuit of high-quality, phase-pure and lead-free two-dimensional MHP materials and large-area fabrication capability for x-ray detectors are among the research hotspots. In this review, we first give a brief introduction of the crystallographic structure, optoelectronic characteristics and preparation methods of high-quality two-dimensional perovskites. In addition, we overview the general working principles of direct and indirect x-ray detection processes and the corresponding performance metrics from the perspective of detection and imaging. Furthermore, we provide a comprehensive discussion on the recent advances in 2D perovskite x-ray detectors and imaging devices. Finally, we pinpoint several major obstacles of 2D x-ray detectors that should be overcome in the near future.

To reach the target of carbon neutral, a transition from fossil energy to renewable energy is unavoidable. Photovoltaic technology is considered one of the most prominent sources of renewable energy. Recently, metal halide perovskite materials have attracted tremendous interest in the areas of optoelectronic devices due to their ease of processing and outstanding performance. To date, perovskite solar cells (PSCs) have shown high power conversion efficiency up to 25.7% and 31.3% for the perovskite-silicon tandem solar cells, which promises to revolutionize the PV landscape. However, the stability of PSCs under operating conditions has yet to match state-of-the-art silicon-based solar cell technology, in which the stability of the absorbing layer and relevant interfaces is the primary challenge. These issues become more serious in the larger area solar modules due to the additional interfaces and more defects within the perovskite. Bilayer perovskite film composed of a thin low dimensional perovskite layer and a three-dimensional perovskite layer shows great potential in fabricating solar cells with high efficiency and stability simultaneously. In this review, recent advancements, including composition design and processing methods for constructing bilayer perovskite films are discussed. We then analyze the challenges and resolutions in deposition bilayer perovskite films with scalable techniques. After summarizing the beneficial effect of the bilayer structure, we propose our thinking of feasible strategies to fabricate high efficiency perovskite solar modules with a long lifetime. Finally, we outline the directions for future work that will push the perovskite PV technology toward commercialization.

Organic–inorganic halide perovskites have been intensively investigated as potential photovoltaic materials due to their exceptional optoelectronic properties and their successful applications in perovskite solar cells (PSCs). However, a large number of defect states still exist in the PSCs so far and are detrimental to their power conversion efficiencies (PCEs) and stability. Here, an effective strategy of incorporating single-crystalline graphene quantum dots (GQDs) into the perovskite films is proposed to passivate the defect states. Intriguingly, the GQD-modified perovskite films exhibit purer phase structure, higher quality of morphology, and higher electrical conductivity when compared with the control perovskite films. All of the advantages caused by the incorporation of the GQDs lead to fast carrier separation and transport, long carrier lifetime, and low nonradiative recombination in the PSCs based on the GQD-modified perovskite films. As a result, this kind of PSC displays an increase in all photovoltaic parameters, and its PCE shows an enhancement of more than 20% when compared with the control PSC. Moreover, this novel PSC is demonstrated to have long-term stability and resistibility against heat and moisture. Our findings provide an insight into how to passivate the defect states and enhance the electrical conductivities in the perovskites and pave the way for their further exploration to achieve higher photovoltaic performances.