Defect passivation strategies in perovskites for an enhanced photovoltaic performance

Fu, Lin; Li, Hui; Lian, Wang; Yin, Ranyu; Li, Bo; Yin, Longwei

doi:10.1039/d0ee01767a

Cited by 307 publications

(247 citation statements)

References 315 publications

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“…b) As highlighted in this review, constructing novel semiconductor photoanode systems from the nanostructure-interface engineering perspective is the top challenge to realize highefficient PEC performance. In the photovoltaic fields, many promising materials have emerged with excellent power conversion performance, such as black phosphorus, [289] organicinorganic hybrid perovskite, [290,291] all-inorganic perovskite materials, [292,293] and MXenes. [294] It is of great interest to study whether these materials can also be applied in PEC reactions.…”

Section: Discussionmentioning

confidence: 99%

Engineering Nanostructure–Interface of Photoanode Materials Toward Photoelectrochemical Water Oxidation

et al. 2021

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In practical applications, solar energy is usually converted to other forms of energy, such as electric energy, [9][10][11] chemical energy, [12,13] thermal energy, [14,15] so as to facilitate further transportation and storage. Among them, photoelectrochemical (PEC) reactions from water to hydrogen, CO 2 to C2+ products, and N 2 to NH 3 in the aqueous-based environment have been considered to be quite promising solar-chemical energy conversion pathways. [16][17][18][19] Unlike the traditional water electrolyzing system, the most ideal PEC reaction system can be selfdriven by illumination without external bias. Utilizing the electron-hole carriers generated from the semiconductor photoelectrode, redox reactions take place separately on the photocathode and photoanode. However, as the water oxidation reaction involves a complex four-proton coupled multi-electron process (2H 2 O + 4h + → O 2 + 4H + , E o = 1.23 V vs reversible hydrogen electrode (RHE)), it makes the water oxidation reaction the rate-control step in the watersplitting reaction. [20] Therefore, developing high-performance photo anodes is of great fundamental importance and interest.At the present stage, TiO 2 is the most studied and applied semiconductor photoelectrocatalyst, due to its outstanding chemical stability. [21][22][23] However, as a wide bandgap semiconductor (anatase TiO 2 : 3.2eV, rutile TiO 2 : 3.0 eV), TiO 2 can only respond to the ultraviolet light. Meanwhile, as an intrinsic semiconductor, the bulk/surficial carrier recombination of TiO 2 greatly hinders its practical application. [24][25][26][27] In that case, some narrow bandgap semiconductors are also applied as the photoanode materials, such as Ta 3 N 5 (bandgap 2.1 eV), [28,29] BiVO 4 (bandgap 2.4 eV), and α-Fe 2 O 3 (bandgap 2.1 eV). [30][31][32] However, many of these narrow bandgap materials suffer from poor chemical stability and sluggish interfacial charge injection. [33][34][35] As intrinsic semiconductor materials, both wide and narrow bandgap semiconductor photoanode materials are suffering from the poor bulk-phase carrier separation, intense surficial e − /h + trapping recombination, and sluggish electrode/electrolyte carrier injection kinetics. [36][37][38][39] Fortunately, with the continuous investment of researchers, a series of modification methods have been established and the PEC water oxidation performance of semiconductor photoanode materials has been significantly improved. [32,[40][41][42][43][44] Among various strategies, nanostructure-interface engineering is widely regarded as an effective method to improve the PEC water oxidation performance: [40,41] the light-harvesting performance can be enhanced by the widened optical Photoelectrochemical (PEC) water oxidation based on semiconductor materials plays an important role in the production of clean fuel and value-added chemicals. Nanostructure-interface engineering has proven to be an effective way to construct highly efficient PEC water oxidation photoanodes with good light capture, carrier transport, and ...

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Section: Discussionmentioning

confidence: 99%

Engineering Nanostructure–Interface of Photoanode Materials Toward Photoelectrochemical Water Oxidation

et al. 2021

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“…As defects are vulnerable sites that are susceptible to moisture stimulation to trigger perovskite degradation, they are considered the starting points and accelerant in the degradation of devices. [ 46–48 ] And it has been proved that the charged trap densities of interfaces of polycrystalline perovskite films are one to two orders of magnitude larger than of the film interior. [ 2 ] In consequence, the improvement in moisture stability comes from the ETL/perovskite interface passivation, which effectively reduces the trap state density.…”

Section: Resultsmentioning

confidence: 99%

Thiazole‐Modified C₃N₄ Interfacial Layer for Defect Passivation and Charge Transport Promotion in Perovskite Solar Cells

Wang

et al. 2021

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Despite the conspicuous achievements in perovskite solar cells (PSCs), further improvement of the power conversion efficiency (PCE) is hindered by substantially detrimental carrier recombination resulting from the high interfacial charge defect density and inferior charge transport kinetics. Herein, an interface engineering strategy is developed to introduce a Lewis base thiophene or thiazole–modified C3N4 layer at the electron transfer layer (ETL)/perovskite interface to constitute a stepwise energy band alignment and passivate defects at interfaces of the perovskite film. Attributed to its well‐matched energy level with TiO2 and perovskite, the charge extraction efficiency and charge transfer dynamics can be promoted remarkably, greatly inhibiting charge recombination at the interface. Furthermore, thiophene and thiazole can donate the lone pair electrons in S or N atoms to undercoordinated Pb2+, which effectively passivates the electronic trap states caused by halogen vacancies, thereby greatly minimizing trap‐assisted nonradiative recombination in the PSCs. Eventually, the thiazole–C3N4/perovskite‐based devices acquire an outstanding efficiency of 19.23%, supported by an enhanced open‐circuit voltage (VOC) of 1.11 V with improved moisture stability. This work provides an avenue for interfacial energy level modulation and defect passivation strategies for a rational interface microstructure design for meliorating the performance of PSCs.

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“…These traps aid in faster transport of charge carriers due to their proximity to the CBM, ease of de-trapping into the CBM, and lowering of the dominant non-radiative recombination processes in organic lead halide perovskites 38 , 39 , which will result in typically lower carrier transport times and higher device efficiency compared to deeper and slower trapping events. In solar cells, this can lead to an increase of the open-circuit voltage ( V oc ) from carriers that can be extracted before trap-assisted recombination occurs 40 . The distinctive use of temperature as a ruler for energy measurement is one of the unique features for the ultra-shallow trap levels revealed by the UPCS.…”

Section: Resultsmentioning

confidence: 99%

“…Along with an understanding of the composition and structural origins of the trap states, we can tune and manipulate the trap dynamic properties, such as trapping, de-trapping rates, and their interplay with trap properties, such as capture cross section, trap level, and trap density to fundamentally improve device efficiency and stability performance. This can be done by defect passivation to convert deep traps to ultra-shallow trap through chemical passivation in solution-processed materials 40 , where an increase in the ratio between shallow and deep traps will greatly improve device efficiency and response times. Steady-state devices such as solar cells operate under constant light and although they will continuously generate excited carriers, a majority will recombine in deep traps thus reducing efficiency.…”

Section: Discussionmentioning

confidence: 99%

In-situ observation of trapped carriers in organic metal halide perovskite films with ultra-fast temporal and ultra-high energetic resolutions

et al. 2021

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We in-situ observe the ultrafast dynamics of trapped carriers in organic methyl ammonium lead halide perovskite thin films by ultrafast photocurrent spectroscopy with a sub-25 picosecond time resolution. Upon ultrafast laser excitation, trapped carriers follow a phonon assisted tunneling mechanism and a hopping transport mechanism along ultra-shallow to shallow trap states ranging from 1.72–11.51 millielectronvolts and is demonstrated by time-dependent and independent activation energies. Using temperature as an energetic ruler, we map trap states with ultra-high energy resolution down to < 0.01 millielectronvolt. In addition to carrier mobility of ~4 cm2V−1s−1 and lifetime of ~1 nanosecond, we validate the above transport mechanisms by highlighting trap state dynamics, including trapping rates, de-trapping rates and trap properties, such as trap density, trap levels, and capture-cross sections. In this work we establish a foundation for trap dynamics in high defect-tolerant perovskites with ultra-fast temporal and ultra-high energetic resolution.

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Defect passivation strategies in perovskites for an enhanced photovoltaic performance

Abstract: Since the first introduction of the organic-inorganic hybrid perovskite in the field of optoelectronics, extraordinary progress in both photoelectric-conversion-efficiency and stability of perovskite solar cells (PSCs) have been witnessed. However,...

Cited by 307 publications

References 315 publications

Engineering Nanostructure–Interface of Photoanode Materials Toward Photoelectrochemical Water Oxidation

Engineering Nanostructure–Interface of Photoanode Materials Toward Photoelectrochemical Water Oxidation

Thiazole‐Modified C₃N₄ Interfacial Layer for Defect Passivation and Charge Transport Promotion in Perovskite Solar Cells

In-situ observation of trapped carriers in organic metal halide perovskite films with ultra-fast temporal and ultra-high energetic resolutions

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Defect passivation strategies in perovskites for an enhanced photovoltaic performance

Abstract: Since the first introduction of the organic-inorganic hybrid perovskite in the field of optoelectronics, extraordinary progress in both photoelectric-conversion-efficiency and stability of perovskite solar cells (PSCs) have been witnessed. However,...

Cited by 307 publications

References 315 publications

Engineering Nanostructure–Interface of Photoanode Materials Toward Photoelectrochemical Water Oxidation

Engineering Nanostructure–Interface of Photoanode Materials Toward Photoelectrochemical Water Oxidation

Thiazole‐Modified C3N4 Interfacial Layer for Defect Passivation and Charge Transport Promotion in Perovskite Solar Cells

In-situ observation of trapped carriers in organic metal halide perovskite films with ultra-fast temporal and ultra-high energetic resolutions

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Thiazole‐Modified C₃N₄ Interfacial Layer for Defect Passivation and Charge Transport Promotion in Perovskite Solar Cells