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Reviewing and understanding the stability mechanism of halide perovskite solar cells
摘要： Finding sustainable and renewable energy to replace traditional fossil fuel is critical for reducing greenhouse gas emission and avoiding environment pollution. Solar cells that convert energy of sunlight into electricity offer a viable route for solving this issue. At present, halide perovskites are the most potential candidate materials for solar cell with considerable power conversion efficiency, whereas their stability remains a challenge. In this work, we summarize four different key factors that influence the stability of halide perovskites: (a) effect of environmental moisture on the degradation of halide perovskites. The performance of halide perovskite solar cells is reduced due to hydrated crystal hinders the diffusion of photo-generated carriers, which can be solved by materials encapsulation technique; (b) photo-induced instability. Through uncovering the underlying physical mechanism, we note that materials engineering or novel device structure can extend the working life of halide perovskites under continuous light exposure; (c) thermal stability. Halide perovskites are rapidly degraded into PbI2 and volatile substances as heating due to lower formation energy, whereas hybrid perovskite is little changed; (d) electric field effect in the degradation of halide perovskites. The electric field impacts significantly on the carrier separation, changes direction of photo-induced currents and generates switchable photovoltaic effect. For each key factor, we have shown in detail the underlying physical mechanisms and discussed the strategies to overcome this stability difficulty. We expect this review from both theoretical and experimental points of view can be beneficial for development of perovskite solar cell materials and promotes practical applications.
关键词： stability mechanism,ion diffusion,perovskite solar cell
更新于2025-09-23 15:21:01
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Cations Functionalized Carbon Nano‐Dots Enabling Interfacial Passivation and Crystallization Control for Inverted Perovskite Solar Cells
摘要： Realizing the full potential of perovskite photovoltaic requires stringent control over nonradiative losses in the devices. Herein, the interfacial carrier recombination of inverted planar perovskite solar cells (PSCs) is suppressed using rationally designed natriumion-functionalized carbon nano-dots (CNDs@Na). The binding effect of carbon dots on Na+ inhibits the interstitial occupancy of alkali cations and reduces the microstrain of the polycrystalline film. Furthermore, modified surface wettability improves the ordering and crystal size of perovskite, which restrains ion diffusion and improves interfacial contact, leading to reduced interfacial charge recombination. Consequently, the effective interfacial passivation and crystallization control enhance the photovoltaic performance and long-term stability of PSCs, resulting in an efficiency of over 20% with negligible hysteresis.
关键词： natriumion-functionalized carbon nano-dots,perovskite solar cells,ion diffusion,trap densities,interface modifications
更新于2025-09-19 17:13:59
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Influence of Surface Ligands on Energetics at FASnI <sub/>3</sub> /C <sub/>60</sub> Interfaces and Their Impact on Photovoltaic Performance
摘要： Interfacial chemistry and energetics significantly impact the performance of photovoltaic devices. In the case of Pb-containing organic metal halide perovskites, photoelectron spectroscopy has been used to determine the energetic alignment of frontier electronic energy levels at various interfaces present in the photovoltaic device. For the Sn-containing analogues, which are less toxic, no such measurements have been made. Through a combination of inverse, and X-ray photoelectron spectroscopy ultraviolet, (UPS, IPES, and XPS, respectively) measurements taken at varying thickness increments during stepwise deposition of C60 on FASnI3, we present the first direct measurements of the frontier electronic energy levels across the FASnI3/C60 interface. The results show band bending in both materials and transport gap widening in FASnI3 at the interface with C60. The XPS results show that iodide diffuses into C60 and results in n-doping of C60. This iodide diffusion out of FASnI3 impacts the valence and conduction band energies of FASnI3 more than the core levels, with the core level shifts displaying a different trend than the valence and conduction bands. Surface treatment of FASnI3 with carboxylic acids and bulky ammonium substituted surface ligands results in slight alterations in the interfacial energetics, and all surface ligands result in similar or improved PV performance relative to the untreated devices. The greatest PV stability results from treatment with a fluorinated carboxylic acid derivative; however, iodide diffusion is still observed to occur with this surface ligand.
关键词： perovskite solar cell,formamidinium tin iodide,interfacial energetics,inverse photoelectron spectroscopy,surface modification,photoelectron spectroscopy,ion diffusion
更新于2025-09-12 10:27:22
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Interface Engineering in Hybrid Iodide CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> Perovskites Using Lewis Base and Graphene toward High-Performance Solar Cells
摘要： Photovoltaic solar cells based on organic-inorganic hybrid halide perovskites have achieved a substantial breakthrough via advanced interface engineerings. Reports have emphasized that combining the hybrid perovskites with Lewis base and/or graphene can definitely improve the performance through surface trap passivation and band alignment alteration; the underlying mechanisms are not yet fully understood. Here, using density functional theory calculations, we show that upon the formation of CH3NH3PbI3 interfaces with three different Lewis base molecules and graphene, the binding strength with S -donors thiocarbamide and thioacetamide is higher than with O-donor dimethyl sulfoxide, while the interface dipole and work function reduction tend to increase from S -donors to O-donor. We provide evidences of deep trap states elimination in the S -donor perovskite interfaces through the analysis of defect formation on the CH3NH3PbI3(110) surface, and of stability enhancement by estimation of activation barriers for vacancy-mediated iodine atom migrations. These theoretical predictions are in line with the experimental observation of performance enhancement in the perovskites prepared using thiocarbamide.
关键词： Perovskite solar cells,ion diffusion,defect,Lewis base,work function,graphene
更新于2025-09-11 14:15:04