Charge behavior modulation by titanium-carbide quantum dots and nanosheets for efficient perovskite solar cells
TL;DR: In this paper, the authors explored a promising strategy to exploit MXenes in the application of perovskite solar cells (PSCs) by taking advantage of zero and two-dimensional Ti3C2, achieving an enhancement of photoelectric conversion efficiency from 12.0% to 17.1%.
About: This article is published in Materials Today Energy.The article was published on 2020-12-01. It has received 20 citations till now. The article focuses on the topics: Perovskite (structure) & Quantum dot.
Citations
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TL;DR: In this paper , functionalized Ti3C2Fx quantum dots (QDs) are selected as interface passivators to enhance the performance of CsPbI3 PSCs.
Abstract: CsPbI3 inorganic perovskites have attracted significant attention due to their desirable bandgap for tandem solar cells and excellent thermal stability. However, CsPbI3 perovskite solar cells (PSCs) still exhibit low efficiency and high energy loss due to nonradiative recombination. Herein, functionalized Ti3C2Fx quantum dots (QDs) are prepared and selected as interface passivators to enhance the performance of CsPbI3 PSCs. The systematic experimental results reveal that Ti3C2Fx QDs serve as effective passivators mainly in three aspects: 1) p‐type Ti3C2Fx QDs can tune the energy level of perovskite films and provide an efficient pathway for hole transfer; 2) Ti3C2Fx QDs can effectively passivate defects and reduce interfacial nonradiative recombination, and 3) Ti3C2Fx QDs form a barrier layer to prevent water invasion and improve the stability of CsPbI3 PSCs. Consequently, the champion CsPbI3 PSC with Ti3C2Fx QDs treatment exhibits an excellent efficiency of 20.44% with a high open‐circuit voltage of 1.22 V. Meanwhile, the corresponding device without encapsulation retained 93% of its initial efficiency after 600 h of storage in ambient air.
28 citations
TL;DR: In this paper, the fundamental properties and preparation of pure and functionalized two-dimensional transition-metal carbides, carbonitrides and nitrides, as well as their optoelectronic applications are summarized.
Abstract: Since the first discovery of Ti3C2 in 2011, two-dimensional (2D) transition-metal carbides, carbonitrides and nitrides, known as MXenes, have attracted significant attention. Due to their outstanding electronic, optical, mechanical, and thermal properties, versatile structures and surface chemistries, Ti3C2 MXenes have emerged as new candidates with great potential for applications in optoelectronic devices, such as photovoltaics, photodetectors and photoelectrochemical devices. The excellent metallic conductivity, high anisotropic carrier mobility, good structural and chemical stabilities, high optical transmittance, excellent mechanical strength, tunable work functions, and wide range of optical absorption properties of Ti3C2 MXene nanostructures are the key to their success in a number of electronic and photonic device applications. Herein, we summarize the fundamental properties and preparation of pure Ti3C2 MXenes, functionalized Ti3C2 MXenes and their hybrid nanocomposites, as well as their optoelectronic applications. In the end, the perspective and current challenges of Ti3C2 MXenes toward the development of advanced MXene-based nanostructures are briefly discussed for future optoelectronic applications.
24 citations
TL;DR: In this paper , an indirect Z-scheme MXene quantum dots (MQDs) bridged In 2 S 3 /SmFeO 3 (IMS) heterojunction was successfully fabricated.
20 citations
TL;DR: In this paper, the progress made so far in using Ti3C2Tx MXene materials in the building blocks of perovskite solar cells such as electrodes, hole transport layer (HTL), electron transport layer(ETL), and perovsite photoactive layer is reviewed.
Abstract: Application of MXene materials in perovskite solar cells (PSCs) has attracted considerable attention owing to their supreme electrical conductivity, excellent carrier mobility, adjustable surface functional groups, excellent transparency and superior mechanical properties. This article reviews the progress made so far in using Ti3C2Tx MXene materials in the building blocks of perovskite solar cells such as electrodes, hole transport layer (HTL), electron transport layer (ETL) and perovskite photoactive layer. Moreover, we provide an outlook on the exciting opportunities this recently developed field offers, and the challenges faced in effectively incorporating MXene materials in the building blocks of PSCs for better operational stability and enhanced performance.
20 citations
TL;DR: In this paper , the authors introduced the Cl-terminated Ti3C2Clx QDs as additives in perovskite precursor solution by one-step deposition method, and they achieved an enhanced efficiency of 21.31% with an ultrahigh open-circuit voltage of 1.19 V and negligible hysteresis.
20 citations
References
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TL;DR: Two organolead halide perovskite nanocrystals were found to efficiently sensitize TiO(2) for visible-light conversion in photoelectrochemical cells, which exhibit strong band-gap absorptions as semiconductors.
Abstract: Two organolead halide perovskite nanocrystals, CH3NH3PbBr3 and CH3NH3PbI3, were found to efficiently sensitize TiO2 for visible-light conversion in photoelectrochemical cells. When self-assembled on mesoporous TiO2 films, the nanocrystalline perovskites exhibit strong band-gap absorptions as semiconductors. The CH3NH3PbI3-based photocell with spectral sensitivity of up to 800 nm yielded a solar energy conversion efficiency of 3.8%. The CH3NH3PbBr3-based cell showed a high photovoltage of 0.96 V with an external quantum conversion efficiency of 65%.
16,634 citations
TL;DR: Two studies show, using a variety of time-resolved absorption and emission spectroscopic techniques, that perovskite materials manifest relatively long diffusion paths for charge carriers energized by light absorption, highlighting effective carrier diffusion as a fruitful parameter for further optimization.
Abstract: Low-temperature solution-processed photovoltaics suffer from low efficiencies because of poor exciton or electron-hole diffusion lengths (typically about 10 nanometers). Recent reports of highly efficient CH3NH3PbI3-based solar cells in a broad range of configurations raise a compelling case for understanding the fundamental photophysical mechanisms in these materials. By applying femtosecond transient optical spectroscopy to bilayers that interface this perovskite with either selective-electron or selective-hole extraction materials, we have uncovered concrete evidence of balanced long-range electron-hole diffusion lengths of at least 100 nanometers in solution-processed CH3NH3PbI3. The high photoconversion efficiencies of these systems stem from the comparable optical absorption length and charge-carrier diffusion lengths, transcending the traditional constraints of solution-processed semiconductors.
5,882 citations
TL;DR: In this paper, the triple cation perovskite photovoltaics with inorganic cesium were shown to be thermally more stable, contain less phase impurities and are less sensitive to processing conditions.
Abstract: Today's best perovskite solar cells use a mixture of formamidinium and methylammonium as the monovalent cations. With the addition of inorganic cesium, the resulting triple cation perovskite compositions are thermally more stable, contain less phase impurities and are less sensitive to processing conditions. This enables more reproducible device performances to reach a stabilized power output of 21.1% and ∼18% after 250 hours under operational conditions. These properties are key for the industrialization of perovskite photovoltaics.
3,470 citations
TL;DR: The trap states on the surface and grain boundaries of the perovskite materials are demonstrated to be the origin of photocurrent hysteresis and that the fullerene layers deposited onperovskites can effectively passivate these charge trap states and eliminate the notorious photocurrent Hysteresi.
Abstract: The large photocurrent hysteresis observed in many organometal trihalide perovskite solar cells has become a major hindrance impairing the ultimate performance and stability of these devices, while its origin was unknown. Here we demonstrate the trap states on the surface and grain boundaries of the perovskite materials to be the origin of photocurrent hysteresis and that the fullerene layers deposited on perovskites can effectively passivate these charge trap states and eliminate the notorious photocurrent hysteresis. Fullerenes deposited on the top of the perovskites reduce the trap density by two orders of magnitude and double the power conversion efficiency of CH(3)NH(3)PbI(3) solar cells. The elucidation of the origin of photocurrent hysteresis and its elimination by trap passivation in perovskite solar cells provides important directions for future enhancements to device efficiency.
2,440 citations
TL;DR: This work identifies an anomalous hysteresis in the current-voltage curves of perovskite solar cells, hypothesizes three possible origins of the effect, and discusses its implications on device efficiency and future research directions.
Abstract: Perovskite solar cells have rapidly risen to the forefront of emerging photovoltaic technologies, exhibiting rapidly rising efficiencies. This is likely to continue to rise, but in the development of these solar cells there are unusual characteristics that have arisen, specifically an anomalous hysteresis in the current–voltage curves. We identify this phenomenon and show some examples of factors that make the hysteresis more or less extreme. We also demonstrate stabilized power output under working conditions and suggest that this is a useful parameter to present, alongside the current-voltage scan derived power conversion efficiency. We hypothesize three possible origins of the effect and discuss its implications on device efficiency and future research directions. Understanding and resolving the hysteresis is essential for further progress and is likely to lead to a further step improvement in performance.
2,205 citations