Perovskite (structure)

About: Perovskite (structure) is a research topic. Over the lifetime, 51482 publications have been published within this topic receiving 1541750 citations.

Two-Dimensional Materials for Halide Perovskite-Based Optoelectronic Devices

Abstract: Halide perovskites have high light absorption coefficients, long charge carrier diffusion lengths, intense photoluminescence, and slow rates of non-radiative charge recombination. Thus, they are attractive photoactive materials for developing high-performance optoelectronic devices. These devices are also cheap and easy to be fabricated. To realize the optimal performances of halide perovskite-based optoelectronic devices (HPODs), perovskite photoactive layers should work effectively with other functional materials such as electrodes, interfacial layers and encapsulating films. Conventional two-dimensional (2D) materials are promising candidates for this purpose because of their unique structures and/or interesting optoelectronic properties. Here, we comprehensively summarize the recent advancements in the applications of conventional 2D materials for halide perovskite-based photodetectors, solar cells and light-emitting diodes. The examples of these 2D materials are graphene and its derivatives, mono- and few-layer transition metal dichalcogenides (TMDs), graphdiyne and metal nanosheets, etc. The research related to 2D nanostructured perovskites and 2D Ruddlesden-Popper perovskites as efficient and stable photoactive layers is also outlined. The syntheses, functions and working mechanisms of relevant 2D materials are introduced, and the challenges to achieving practical applications of HPODs using 2D materials are also discussed.

High‐Performance Fully Printable Perovskite Solar Cells via Blade‐Coating Technique under the Ambient Condition

Abstract: In order to fabricate large-area PVSCs, one of the critical challenges is to understand the infl uence of ambient environment on resultant perovskite thin-fi lms since perovskite crystals are sensitive to humidity under ambient condition. It has been shown that perovskite crystals degrade gradually when they are in contact with ambient moisture for certain time. [ 31,32 ] Therefore, most of the high performance perovskite solar cells are prepared in glovebox to avoid contacting moisture. However, fabricating PVSCs under ambient condition is inevitable if we desire to transition from laboratory research into large-scale applications. Lately, there are several encouraging reports about allowing limited amount of moisture to facilitate the perovskite crystallization and improve the performance of resulting device. [ 33,34 ] However, there are no detailed underlying mechanisms explained on how moisture affects perovskite crystallization so far. To alleviate these problems, we have investigated the feasibility of achieving fully printable PVSCs by the blade-coating technique under the ambient condition. The blade-coating fabrication has been widely used to fabricate OSCs and is proven to be a simple, environment-friendly, and low-cost method for the solution-processed photovoltaic. Compared to the screen printing, it not only can print nanoparticles, but also can print all kinds of solutions with any concentration. Moreover, the fi lm morphology control of the blade-coating method is much better than the spray coating and roll-to-roll printing; high-quality photoactive layers with controllable thickness can be accomplished by using a precisely translational blade under the ambient condition with controlled relative humidity. The PVSCs with a confi guration of ITO/poly(3,4-ethylenedioxy-thiophene):poly(4-styrenesulfonate) (PEDOT:PSS)/ CH 3 NH 3 PbI X Cl 3− X /[6,6]-phenyl-C 61 butyric acid methyl ester (PC 61 BM)/Bis-C 60 /Ag were fabricated to realize the fully printable process, as illustrated in Figure 1 a. All constituent interlayers, except for the Ag top electrode, were prepared via blade-coating. The coating conditions were optimized to allow the preparation of high-quality interlayer fi lms. Especially, the effect of humidity was carefully investigated and monitored to facilitate the crystallization of perovskite fi lms under ambient condition. Finally, high PCE (10.44% ± 0.23%) device could be achieved after optimizing the blade-coating process and relative humidity in environment. Moreover, a high-performance fl exible PVSC with a PCE of 7.14% ± 0.31% was demonstrated for the fi rst time using this low-temperature (<150 °C) fully printable process. The exceptional photovoltaic properties demonstrated recently for organic–inorganic halide perovskites (such as CH 3 NH 3 PbX 3 (X = Cl, Br, or I)) have attracted great attention from researchers. [ 1–8 ] The promising features of these perovskites include broad and intense absorption spectra, [ 9 ] appropriate semiconducting properties, [ 10 ] long carrier diffusion length, [ 11,12 ]

Approaching the fill factor Shockley–Queisser limit in stable, dopant-free triple cation perovskite solar cells

Abstract: Perovskite solar cells now compete with their inorganic counterparts in terms of power conversion efficiency, not least because of their small open-circuit voltage (VOC) losses. A key to surpass traditional thin-film solar cells is the fill factor (FF). Therefore, more insights into the physical mechanisms that define the bias dependence of the photocurrent are urgently required. In this work, we studied charge extraction and recombination in efficient triple cation perovskite solar cells with undoped organic electron/hole transport layers (ETL/HTL). Using integral time of flight we identify the transit time through the HTL as the key figure of merit for maximizing the fill factor (FF) and efficiency. Complementarily, intensity dependent photocurrent and VOC measurements elucidate the role of the HTL on the bias dependence of non-radiative and transport-related loss channels. We show that charge transport losses can be completely avoided under certain conditions, yielding devices with FFs of up to 84%. Optimized cells exhibit power conversion efficiencies of above 20% for 6 mm2 sized pixels and 18.9% for a device area of 1 cm2. These are record efficiencies for hybrid perovskite devices with dopant-free transport layers, highlighting the potential of this device technology to avoid charge-transport limitations and to approach the Shockley–Queisser limit.

Perovskites for Solar Thermoelectric Applications: A First Principle Study of CH3NH3AI3 (A = Pb and Sn)

Abstract: Hybrid organic/inorganic CH3NH3AI3 (A = Pb and Sn) perovskites have been recognized as promising photovoltaic materials. Using ab initio calculations, we showed that these systems may also be promising materials for solar thermoelectric applications. We found that their large carrier mobilities mainly originate from a combination of the small effective masses of electrons and holes and a relatively weak carrier–phonon interaction. We propose that by tuning the carrier concentration to values of the order of ∼1018cm–3, the thermoelectric figure of merit of Sn and Pb based perovskites may reach values ranging from 1 to 2, which could possibly be further increased by optimizing the lattice thermal conductivity through engineering perovskite superlattices.