Planar perovskite solar cells (PSCs) have attracted extensive research attention owing to their simple architecture and manufacturing process. Improving the charge extraction ability of electron ...transport materials (ETMs) is imperative to enhance their power conversion efficiencies (PCEs). Herein, we report low-temperature solution-processed SnO2 nanocrystals (SnO2 NCs) enveloped by amorphous NbOx (SnO2/NbOx) as efficient ETMs for planar PSCs, achieving an impressive PCE of 24.01% with negligible hysteresis, which is significantly superior to that of PSCs made from commercial SnO2 (with PCEs up to 21.96%) and self-developed SnO2 NCs (with PCEs up to 23.01%). The NbOx layer can simultaneously passivate defects at the ETMs/perovskite interface, promote charge extraction from perovskites, and improve the crystallinity of perovskite films. The unencapsulated PSC retains over 85% of its initial efficiency after 1000 h of light soaking (one sun), showing remarkable device stability. Furthermore, the low-temperature processed SnO2/NbOx ETMs are compatible with flexible substrates and present a maximum PCE of 20.00%. This work offers a facile approach to low-temperature processed ETMs with boosted carrier extraction ability, affording excellent device efficiency and stability for planar PSCs.
Commercialization of perovskite solar cells (PSCs) requires developing high-efficiency devices with good stability. Ionic defects existing in the perovskite layer can serve as nonradiative ...recombination centers to deteriorate the performance of PSCs and can introduce chemical degradation of the perovskite material introducing instability issues. Here, passivation molecules with various electron density distributions (EDD) are employed as an ideal model to reveal the role of EDD on defect passivation in perovskite thin films. Power conversion efficiency (PCE) exceeding 21% with good stability in humid air was obtained for planar PSCs with the 4-aminobenzonitrile (ABN) additive, higher than the reference PSCs with a PCE of 20.22%. The improved stability and performance features are attributed to the efficient passivation for charged defects in perovskites by adding ABN, which guarantees a smaller Urbach energy, longer carrier lifetime, and less traps in the perovskite films.
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IJS, KILJ, NUK, PNG, UL, UM
X-ray detection has been widely used in medical imaging, security inspection, and industrial non-destructive tests. Halide perovskite X-ray detectors have attracted increasing attention due to their ...high sensitivity and low detection limit, but the notorious ion migration leads to poor operational stability. It is reported that the low dimensional structure can effectively suppress the ion migration of perovskites, thus greatly improving the stability of the detectors. This review introduces the working mechanism, key performance parameters of perovskite X-ray detectors, and summarizes the recent progress of lowdimensional perovskite materials and their application in direct X-ray detectors. The relationship between the structural characteristics of low-dimensional perovskite materials and their X-ray detection performance was systematically analyzed. Low-dimensional perovskite is a promising candidate for the preparation of X-ray detectors with both high sensitivity and stability. Further optimization of det
Abstract Quasi-two-dimensional (Q-2D) perovskite exhibits exceptional photoelectric properties and demonstrates reduced ion migration compared to 3D perovskite, making it a promising material for the ...fabrication of highly sensitive and stable X-ray detectors. However, achieving high-quality perovskite films with sufficient thickness for efficient X-ray absorption remains challenging. Herein, we present a novel approach to regulate the growth of Q-2D perovskite crystals in a mixed atmosphere comprising methylamine (CH 3 NH 2 , MA) and ammonia (NH 3 ), resulting in the successful fabrication of high-quality films with a thickness of hundreds of micrometers. Subsequently, we build a heterojunction X-ray detector by incorporating the perovskite layer with titanium dioxide (TiO 2 ). The precise regulation of perovskite crystal growth and the meticulous design of the device structure synergistically enhance the resistivity and carrier transport properties of the X-ray detector, resulting in an ultrahigh sensitivity (29721.4 μC Gy air −1 cm −2 ) for low-dimensional perovskite X-ray detectors and a low detection limit of 20.9 nGy air s −1 . We have further demonstrated a flat panel X-ray imager (FPXI) showing a high spatial resolution of 3.6 lp mm −1 and outstanding X-ray imaging capability under low X-ray doses. This work presents an effective methodology for achieving high-performance Q-2D perovskite FPXIs that holds great promise for various applications in imaging technology.
The perovskite lattice strain correlating to its physical chemistry not only impacts the optoelectronic properties but also the long‐term stability. The relaxation of perovskite lattice strain has ...been recognized as an important pathway to improve photovoltaic performance and broaden the application scope. With the growth of research interest and the thriving of synthetical approaches in strain engineering, it is particularly necessary to summarize the current strategies to give an in‐depth understanding of the relaxation of lattice strain. Herein, the milestones in strain relaxation studies are summarized and the theoretical simulation and methodological approach to correlate the crystal structure and physical properties at an atomic level is outlined. This perspective provides fundamentals to theoretically predict and experimentally measure the strain relaxation effect and suggests design principles and synthetical strategies for tackling the lattice strain issue for perovskites.
The relaxation of perovskite lattice strain has been recognized as an important pathway to improve photovoltaic performance and broaden the application scope. This perspective provides fundamentals to theoretically predict and experimentally measure the strain relaxation effect and suggests design principles and synthetical strategies for tackling the lattice strain issue for perovskites.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Hydrogen is essential to many industrial processes and could play an important role as an ideal clean energy carrier for future energy supply. Herein, we report for the first time the growth of ...crystalline Cu3P phosphide nanosheets on conductive nickel foam (Cu3P@NF) for electrocatalytic and visible light-driven overall water splitting. Our results show that the Cu3P@NF electrode can be used as an efficient Janus catalyst for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). For OER catalysis, a current density of 10 mA/cm2 requires an overpotential of only ∼320 mV and the slope of the Tafel plot is as low as 54 mV/dec in 1.0 M KOH. For HER catalysis, the overpotential is only ∼105 mV to achieve a catalytic current density of 10 mA cm–2. Moreover, overall water splitting can be achieved in a water electrolyzer based on the Cu3P@NF electrode, which showed a catalytic current density of 10 mA/cm2 under an applied voltage of ∼1.67 V. The same current density can also be obtained using a silicon solar cell under ∼1.70 V for both the HER and the OER. This new Janus Cu3P@NF electrode is made of inexpensive and nonprecious metal-based materials, which opens new possibilities based on copper to exploit overall water splitting for hydrogen production. To the best of our knowledge, such high performance of a copper-based water oxidation and overall water splitting catalyst has not been reported to date.
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IJS, KILJ, NUK, PNG, UL, UM
Trap-dominated non-radiative charge recombination is one of the key factors that limit the performance of perovskite solar cells (PSCs), which was widely studied in methylammonium (MA) containing ...PSCs. However, there is a need to elucidate the defect chemistry of thermally stable, MA-free, cesium/formamidinium (Cs/FA)-based perovskites. Herein, we show that d-penicillamine (PA), an edible antidote for treating heavy metal ions, not only effectively passivates the iodine vacancies (Pb
defects) through coordination with the -SH and -COOH groups in PA, but also finely tunes the crystallinity of Cs/FA-based perovskite film. Benefiting from these merits, a reduction of non-radiative recombination and an increase in photoluminescence lifetime have been achieved. As a result, the champion MA-free device exhibits an impressive power conversion efficiency (PCE) of 22.4%, an open-circuit voltage of 1.163 V, a notable fill factor of 82%, and excellent long-term operational stability. Moreover, the defect passivation strategy can be further extended to a mini module (substrate: 4 × 4 cm
, active area: 7.2 cm
) as well as a wide-bandgap (∼1.73 eV) Cs/FA perovskite system by delivering PCEs of 16.3% and 20.2%, respectively, demonstrating its universality in defect passivation for efficient PSCs.
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IJS, KILJ, NUK, UL, UM, UPUK
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•Uniform CsCu5S3 (CCS) nanocrystals (NCs) were prepared via a hot-injection method.•The surface defects of perovskite films can be effectively passivated by CCS NCs.•Inserting of CCS ...NCs into perovskite solar cells leads to a better band alignment.•The power conversion efficiency is boosted to 22.29% by a layer of CCS NCs.
The ionic nature of perovskites leads to abundant defects at the interface and grain boundaries of perovskite films, which are detrimental to the performance of perovskite solar cells (PSCs). Here, I-I-VI group CsCu5S3 (CCS) nanocrystals (NCs) were used as an interlayer between the perovskite film and hole transport layer in PSCs. The CCS NCs were synthesized via a facile colloidal chemistry approach and exhibited high air stability and strong absorption in the visible-to-near infrared range. The CCS interlayer effectively passivates the interfacial defects, which strongly suppresses non-radiative recombination in the PSCs. The CCS interlayer is favorable for energy levels between the perovskite and HTM to reduce carrier recombination. As a result, the devices with a CCS interlayer delivered a champion power conversion efficiency (PCE) of 22.29% with good reproducibility and stability. In addition, the PSCs retained more than 85% of their original efficiency after storage for approximately 3000 h under ambient conditions. This work paves a new avenue for the development of high-efficiency PSCs and the application of Cu-based chalcogenide NCs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPUK, ZAGLJ, ZRSKP
Halide perovskites have attracted significant research interests in the X-ray detection and imaging field. Their strong X-ray attenuating ability and good carrier transportation endow them with high ...sensitivity, which is better than those of commercialized amorphous selenium (a-Se) and CdZnTe (CZT). However, ion migration has been identified as a critical factor that deteriorates the performance of three-dimensional (3D) lead-based halide perovskite detectors. Moreover, large dark current has hindered their application in low-dose X-ray detection. Another major challenge is to fabricate large area, high-quality thick perovskites that can be integrated with commercial electronic readout backplanes, such as thin-film transistors (TFTs) and complementary metal-oxide-semiconductor (CMOS) transistors, to produce multipixel flat-panel detectors for X-ray imaging. Bismuth-based halide perovskites have been demonstrated to be competitive candidates due to their low ionic migration and small dark current. Fabrication methods, including pressing, membrane filling, blade coating, spray coating
etc.
, will be summarized and discussed in detail. This feature article discusses the potential and challenges in perovskite X-ray detection and imaging, providing new research directions for future development.
Halide perovskites are developed to be sensitive, stable and scalable in the future commercialization process.
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