Band gap tunable hybrid organic−inorganic lead halide perovskites (APbX 3 , A = CH 3 NH 3 + and NH 2 CHNH 2 + , and X = Cl, Br, or I) have attracted significant attention in optoelectronic-and photovoltaic-related fields on account of their outstanding optoelectronic properties. Single crystals of hybrid perovskites, such as CH 3 NH 3 PbI 3 and CH 3 NH 3 PbBr 3 , were certified to be advantageous over thin films as photodetectors. However, their resistance toward heat and moisture hinders their future development. Fully inorganic perovskite CsPbBr 3 stands a chance to fill the gap as a novel photodetector with perovskite structure. We revealed the growth of CsPbBr 3 single crystal was of a 2D nucleation mechanism. Similarities of d values and octahedra arrangements along [101] and [020] orientations restricted single-crystal growth. Under optimized conditions, orthorhombic CsPbBr 3 single crystals with (101) crystallographic facets were grown by using methyl alcohol as antisolvent from saturated DMSO solution. The optoelectronic properties of the single crystal were explored through a metal− semiconductor−metal photodetector device. Meanwhile, their steady and transient performances were also investigated. A highest responsivity of 0.028 A/W and a response time of <100 ms were achieved.
Excess lead iodide (PbI2), as a defect passivation material in perovskite films, contributes to the longer carrier lifetime and reduced halide vacancies for high‐efficiency perovskite solar cells. However, the random distribution of excess PbI2 also leads to accelerated degradation of the perovskite layer. Inspired by nanocrystal synthesis, here, a universal ligand‐modulation technology is developed to modulate the shape and distribution of excess PbI2 in perovskite films. By adding certain ligands, perovskite films with vertically distributed PbI2 nanosheets between the grain boundaries are successfully achieved, which reduces the nonradiative recombination and trap density of the perovskite layer. Thus, the power conversion efficiency of the modulated device increases from 20% to 22% compared to the control device. In addition, benefiting from the vertical distribution of excess PbI2 and the hydrophobic nature of the surface ligands, the modulated devices exhibit much longer stability, retaining 72% of their initial efficiency after 360 h constant illumination under maximum power point tracking measurement.
Organic-inorganic halide perovskite solar cells (PSCs) have a great potential for commercialization owing to their low cost and superior performance. [1] Over the past decade, the power conversion efficiency (PCE) of PSCs has increased from 3.8% [2] to 25.2%, [3] approaching the record efficiency of 26.7% of crystalline silicon solar cells, [4] and becoming one of the most promising candidates for the nextgeneration efficient and low-cost photovoltaic devices. [5] For example, Seok and co-workers introduced additional iodide intoprecursor solutions, resulting in a certified PCE of 22.1%. [6] Recently, Kim et al. investigated the effects of methylammonium chloride (MACl) on the performance of perovskite films and fabricated a device that achieved a certified PCE of 23.5%. [7] It is important to note that all these efficient devices were fabricated with high-temperature-processed TiO 2 mesoporous structures, thus limiting their widespread application. Developing low-temperature-processed electron-transport layer (ETL) [8] for planar structure devices is of great importance. [9] Among them, TiO 2 , [10] SnO 2 , [11] and [6]-phenyl-C 61 -butyric acid methyl ester (PCBM) [12] are the most commonly used ones.The lower efficiency of devices based on planar structures is closely related to insufficient charge extraction [13] and imperfect interfacial band alignment. [14] The insufficient charge extraction between perovskite and ETL can result in charge accumulation, which negatively affects device performance. [15] Therefore, sufficient charge extraction is one of the most important contributors for device efficiency. [16] Recently, researchers have focused on the use of bilayer ETL, [17] and the bilayer stack structure has been demonstrated to be effective for improving device efficiency. As early as 2014, [18] Snaith and co-workers have shown that PSCs with C 60 -modified TiO 2 can significantly enhance electron transfer and result in a largely improved performance of 17.3% and a decrease in hysteretic behavior. Petrozza and co-workers demonstrated that insufficient charge extraction from the perovskite film to the ETL can be remedied using a TiO 2 /PCBM bilayer ETL, and a PCE of 17.9% was achieved. [19] Recently, Choi and co-workers achieved a PCE of 21.1% using SnO 2 @TiO 2 ETL, [20] and Kong and co-workers showed a PCE of 21.4% using the same type of ETL. [21] Numerous other efforts have been undertaken to enhance the performance of PSCs with bilayer ETLs, such as SnO 2 @TiO 2 , [22] SnO 2 /PCBM, [23] An electron-transport layer (ETL) with appropriate energy alignment and enhanced charge transfer is critical for perovskite solar cells (PSCs). However, interfacial energy level mismatch limits the electrical performance of PSCs, particularly the open-circuit voltage (V OC ). Herein, a simple low-temperature-processed In 2 O 3 /SnO 2 bilayer ETL is developed and used for fabricating a new PSC device. The presence of In 2 O 3 results in uniform, compact, and low-trap-density perovskite films. Moreover, the conduction...
Light-up RNA aptamers are valuable tools for fluorescence imaging of RNA in living cells and thus for elucidating RNA functions and dynamics. However, no light-up RNA sensor has been reported for imaging of microRNAs (miRs) in mammalian cells. We report a novel genetically encoded RNA sensor for fluorescent imaging of miRs in living tumor cells using a light-up RNA aptamer that binds to sulforhodamine and separates it from a conjugated contact quencher. On the basis of the structural switching mechanism for molecular beacon, we show that the RNA sensor activates high-contrast fluorescence from the sulforhodamine-quencher conjugate when its stem-loop responsive motif hybridizes with target miR. The RNA sensor can be stably expressed within a designed tRNA scaffold in tumor cells and deliver light-up response to miR target. We also realize the RNA sensor for dual-emission, ratiometric imaging by coexpression of RNA sensor with GFP, enabling quantitative studies of target miR in living cells. Our design may provide a new paradigm for developing robust, sensitive light-up RNA sensors for RNA imaging applications.
Semitransparent solar cells (ST‐SCs) have received great attention due to their promising application in many areas, such as building integrated photovoltaics (BIPVs), tandem devices, and wearable electronics. In the past decade, perovskite solar cells (PSCs) have revolutionized the field of photovoltaics (PVs) with their high efficiencies and facile preparation processes. Due to their large absorption coefficient and bandgap tunability, perovskites offer new opportunities to ST‐SCs. Here, a general overview is provided on the recent advances in ST‐PSCs from materials and devices to applications and some personal perspectives on the future development of ST‐PSCs.
SnO 2 is widely used and one of the most efficient electron transport layers in perovskite solar cells (PSCs). However, SnO 2 films often contain detrimental defects and may also have mismatches in energy level alignment with perovskite films, thus limiting the open-circuit voltage (V OC ). Managing the defects and band structure are critical to reduce energy loss in PSCs. Herein, cobalt chloride hexahydrate (CoCl 2 •6H 2 O) is introduced into a SnO 2 film, which shows favorable energy level alignment and better charge extraction. Correspondingly, an enhanced V OC up to 1.20 V was achieved along with an efficiency of 23.82%, which is the record open-circuit voltage at the optical band gap of 1.54 eV in planar structure PSCs. Moreover, the target devices show enhanced stability, which retains 83.5% of their initial efficiencies after 200 h under continuous irradiation. The doping method provides an effective strategy for reducing energy loss to further enhance the efficiency of PSCs.
Hole transport layers (HTLs) play a crucial role in the efficiency and stability of perovskite solar cells (PSCs). The most efficient PSCs based on spiro-OMeTAD (Spiro) generally have stability problems. Here, NiO x /Spiro HTL has been designed and implemented by combining the advantages of these two films. The results indicated that a device based on a NiO x /Spiro HTL has faster hole extraction ability and better energy alignment than that of a pure Spiro device, thus improving the PCE from 19.8 to 21.66%. Compared with the 60% initial efficiency of Spiro-based devices, the NiO x /Spiro bilayer devices have higher stability and maintain 90% initial efficiency over 1200 h. In this work, NiO x is applied to perovskite devices with N−I−P configuration, which provides a possible mitigation strategy to reduce the V OC deficit for efficient and stable devices.
Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.