Reduced-dimensional perovskite photovoltaics with homogeneous energy landscape

He, Tingwei; Li, Saisai; Jiang, Yuanzhi; Qin, Chaochao; Cui, Minghuan; Qiao, Liang; Xu, Hongxing; Yang, Jiecheng; Long, Run; Wang, Huanhua; Yuan, Mingjian

doi:10.1038/s41467-020-15451-1

Cited by 234 publications

(246 citation statements)

References 41 publications

Supporting

Mentioning

218

Contrasting

Unclassified

Order By: Relevance

“…Under bottom excitation, the evolution of the reducing bleach signals assigned to n = 3, 4, and 5 phases is accompanied by the enhanced bleach signal at n ≈ ∞ phase within the delay time of 300 ps (see Figure 3 a,b), suggesting that the electrons can spontaneously transfer from the smaller n to n ≈ ∞ phases in both the control and aqueous precursor‐based films. [ 35,38,39 ] This process is also observed in the corresponding films under front excitation at early delay time (within 40 ps, see Figure 3c,d), corresponding to the penetration of photons through the n ≈ ∞ phase and resultant charge transfers to the low energy gap phases. It is noteworthy that the TA spectra of control film display multiple higher energy bleach signals at n = 3, 4, and 5 phases under front excitation.…”

Section: Figurementioning

confidence: 60%

Water‐Assisted Crystal Growth in Quasi‐2D Perovskites with Enhanced Charge Transport and Photovoltaic Performance

Wang

et al. 2020

Advanced Energy Materials

View full text Add to dashboard Cite

Perovskite solar cells (PSCs) employing 3D organic-inorganic hybrid perovskite photoabsorbers have received tremendous progress with state-of-the-art power conversion efficiency (PCE) exceeding 25% during the last a dozen years. [1] However, ambient instability of 3D perovskite materials remains a critical obstacle for realistic applications of PSCs. [2,3] A strategy in addressing the poor stability is to reduce the structural dimensionality of perovskites via the introduction of long-chain organic ligands by forming Ruddlesden-Popper (RP) quasi-2D perovskites. [4,5] The organic ligands are bound to the 3D inorganic framework via coulombic interactions, resulting in a layered structure. The general formula of RP-2D perovskites takes the form of (L) 2 A n−1 Pb n I 3n+1 (n = 1, 2, 3, 4…) where A is the methylammonium (MA +), formamidinium (FA +), or cesium (Cs +) cations, L is the bulky organic ligands, e.g., butylammonium (BA +) or 2-phenylethylammonium (PEA +), and n is the number of layers in the [PbI 6 ] 4− octahedral sheets. [4-7] The incorporation of hydrophobic bulky organic ligands can not only enhance the stability of perovskites with minimized permeation of water molecules but also increase the formation energy of perovskites to mitigate thermal degradation and ion migration. [8-10] These merits alongside the quantum confinement have rendered quasi-2D perovskites great potentials for optoelectronic applications with a wide tunability on the bandgap or photophysical properties. [7] Unfavorably, quasi-2D perovskites are generally associated with a large exciton binding energy (hundreds of meV) due to the insulating nature of bulky organic ligands and the specific layered arrangement. [11,12] As a result, charge transport and extraction are hindered in quasi-2D PSCs. To date, the highest reported PCEs of quasi-2D PSCs (n ≤ 5) remain around 18%, [13-15] showing considerable performance gaps with regard to 3D-PSCs. The PCE (η) of photovoltaic cells is determined by the general relation, J V P FF sc oc light η = × × (V oc is the open-circuit voltage, FF is the fill factor, and P light is the illumination intensity). In quasi-2D PSCs, the relatively low J sc is more restrictive for Organic-inorganic hybrid quasi-2D perovskites have shown excellent stability for perovskite solar cells (PSCs), while the poor charge transport in quasi-2D perovskites significantly undermines their power conversion efficiency (PCE). Here, studies on water-controlled crystal growth of quasi-2D perovskites are presented to achieve high-efficiency solar cells. It is demonstrated that the (BA) 2 MA 4 Pb 5 I 16-based PSCs (n = 5) processed with water-containing precursors display an increased short-circuit current density (J sc) of 19.01 mA cm −2 and PCE over 15%. The enhanced performance is attributed to synergetic growths of the 3D and 2D phase components aided by the formed hydration (MAI•H 2 O), leading to modulations on the crystal orientation and phase distribution of various n-value components, which facilitate interphase charge tr...

show abstract

Section: Figurementioning

confidence: 60%

Water‐Assisted Crystal Growth in Quasi‐2D Perovskites with Enhanced Charge Transport and Photovoltaic Performance

Wang

et al. 2020

Advanced Energy Materials

View full text Add to dashboard Cite

show abstract

“…In general, defects in the crystal structure cause PL quenching, which leads to a shortened PL lifetime of photogenerated carriers in the absorber layer. [ 39 ] Here, prolonged PL lifetime of photogenerated carriers may come from a reduction of Shockley–Read–Hall (SRH) recombination via bulk defects in the MAPbI 3 –SDBS film, and indicates a lower defect concentration for MAPbI 3 –SDBS film, [ 59,60 ] further suggesting that the SDBS passivation dramatically inhibits the nonradiative recombination. To more accurately quantitatively assess the trap‐state density ( N t ) of different perovskite films, we fabricated the electron‐only devices with the structure of FTO/SnO 2 /perovskite/PCBM/Au, and measured the dark current–voltage curves of the space charge‐limited current (SCLC) as a function of the different bias voltages, as shown in Figure 3f.…”

Section: Resultsmentioning

confidence: 99%

Surfactant Sodium Dodecyl Benzene Sulfonate Improves the Efficiency and Stability of Air‐Processed Perovskite Solar Cells with Negligible Hysteresis

Zhang

Tang

et al. 2020

Solar RRL

View full text Add to dashboard Cite

The device performance of organic–inorganic hybrid halide perovskite solar cells (PSCs) is highly dependent on the quality of perovskite layer. Herein, a multifunctional chemical additive strategy is reported to simultaneously improve the efficiency and stability of fully air‐processed PSCs. The planner methylammonium lead trihalide (MAPbI3)‐based PSCs incorporating sodium dodecyl benzene sulfonate (SDBS) exhibit a champion power conversion efficiency (PCE) of 19.20% and negligible hysteresis, which is one of the top efficiencies of MAPbI3‐based PSCs made in air. The increased efficiency is due to the reduction of defects and inhibition of ion migration in the perovskite films. Furthermore, the enhancement of device performance and stability can also be ascribed to highly preferred and efficient perovskite crystals protecting the perovskite films from humidity. The corresponding unencapsulated device retains 92.34% of its initial efficiency after 90 days (>2100 h) storage in air and maintains 85.20% of its original PCE after being exposed to 85 °C for 27 h. The results indicate that SDBS is a promising chemical additive to enhance the performance of air‐processed PSCs for future applications.

show abstract

“…[69] Further, the electronic coupling between inorganic layers also has a non-negligible effect on the distance between layers. [70][71][72][73] However, the dielectric constant of organic materials is significantly smaller than that of inorganic materials, which leads to the obvious quantum confinement effect in 2D perovskites. [74] This also indicates that the carrier transport path is limited in the inorganic layer.…”

Section: Natural Quantum Well Structurementioning

confidence: 99%

Crystallization Kinetics in 2D Perovskite Solar Cells

Wang

Lei

et al. 2020

Advanced Energy Materials

140

124

View full text Add to dashboard Cite

volatile decomposition [23] or halide segregation are often observed in hybrid perovskites under various stress conditions (light, [24] thermal, [25] and electric fields [26]); 4) spontaneous phase transition easily occurs for perovskite with unstable crystal structures, particularly for inorganic perovskite. [27-29] To improve the stability of PSCs, researchers attempted numerous methods such as encapsulation, [30] additive engineering, [31] component engineering, [32] etc. [33] However, the PSCs' stability is yet to achieve a perfect solution. Recently, researchers found that the introduction of long-chain organic cations in 3D perovskite as 2D perovskite can block water and oxygen molecules, meanwhile, generate a steric effect to prevent phase transitions, and limit ion migration. [34-36] Hence, fabricating 2D [37,38] or 2D/3D [39-43] mixed perovskite as absorbing layers are effective approaches to improve the stability of PSCs. However, the PCE of 2D PSCs remain lower than that of the 3D ones, which is mainly attributed to the introduction of organic macromolecules that blocks the effective extraction and transport of carriers. [44,45] Fortunately, 2D perovskite usually has three arrangements, namely parallel, perpendicular to the glass substrate or randomly arranged. [46] Manipulating the orientation of the crystal and the phase distribution in the 2D solution-processed perovskite can improve the efficiency and reproducibility of the device. Among them, the most desired arrangement for PSCs is the one that perpendicular to the substrate. Therefore, studying the crystallization kinetics of 2D perovskite is curial to effectively control the film forming process and adjust the crystal orientation (perpendicular to the substrate), which can effectively avoid or reduce the adverse effects of the organic molecular layer and improve device efficiency. [47,48] Nevertheless, few review articles were published on this subject. In this review, we mainly focus on the key issue for controlling crystallization kinetics and summarizing the research progress of their effects on various types of 2D PSCs. We also discuss the crystal/natural quantum well (QW) structure and the original stability for 2D PSCs in detail. Finally, remaining challenges and outlooks are presented. 2. Crystal and Natural Quantum Well Structure The material structure has a substantial impact on performance. [49-51] Properties of 2D and 3D perovskites differ 2D perovskites demonstrate higher moisture stability, oxygen content, thermal stability, and a significantly lower ion migration/phase transition occurrence in comparison to 3D perovskite. These advantages imply huge potential for 2D perovskite in commercial applications in the photovoltaic field. However, the horizontal arrangement of the organic layer severely hinders the transport of carriers, and thus, the power conversion efficiency of 2D perovskite solar cells (PSCs) is significantly lower than that of 3D. Controlling the crystallization orientation to achieve rapid carrier transport can effe...

show abstract

Reduced-dimensional perovskite photovoltaics with homogeneous energy landscape

Cited by 234 publications

References 41 publications

Water‐Assisted Crystal Growth in Quasi‐2D Perovskites with Enhanced Charge Transport and Photovoltaic Performance

Water‐Assisted Crystal Growth in Quasi‐2D Perovskites with Enhanced Charge Transport and Photovoltaic Performance

Surfactant Sodium Dodecyl Benzene Sulfonate Improves the Efficiency and Stability of Air‐Processed Perovskite Solar Cells with Negligible Hysteresis

Crystallization Kinetics in 2D Perovskite Solar Cells

Contact Info

Product

Resources

About