Downscaling micro- and nano-perovskite LEDs
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Inorganic Cs3Bi2I9 lead-free halide perovskite film for large-area X-ray detector via low-cost ambient spray coating
Lead-free Cs3Bi2I9 single crystals have been demonstrated to be promising materials for direct X-ray detectors with remarkable performance. However, their application for 2D X-ray imaging is hindered by their time-consuming preparation and limited crystal size. In this paper, a thick Cs3Bi2I9 perovskite film fabricated via facile spray coating at a low processing temperature, which increases the area of the photoactive film, reduces the processing time, decreases the energy budget and the production cost, and enhances the production yield due to high material utilization, has great potential for commercial applications. Careful control of the processing temperature and intervals during spray coating results in a dense and thick perovskite film with well-stacked perovskite domains. The compact perovskite film enhances the charge transport capability of the Cs3Bi2I9 perovskite film and reduces the dark current density of the X-ray detector. The resultant X-ray detector, prepared through a two-step spray coating process, exhibited a sensitivity of 127.23 μC Gyair−1 cm−2 and a detection limit of 7.4 μGyair s−1. In addition, the device delivers long-term stability with a consistent photoresponse when exposed to consecutive X-ray pulse irradiation.
Improved radicchio seedling growth under CsPbI3 perovskite rooftop in a laboratory-scale greenhouse for Agrivoltaics application
Agrivoltaics, integrating photovoltaic systems with crop cultivation, demands semitransparent solar modules to mitigate soil shadowing. Perovskite Solar Cells (PSC) offer competitive efficiency, low fabrication costs, and high solar transmittance, making them suitable for agrivoltaic applications. However, the impact of PSC light filtering on plant growth and transcriptomics remains underexplored. This study investigates the viability and agronomic implications of the growth of radicchio seedlings (Cichorium intybus var. latifolium) in laboratory-scale greenhouses integrating Perovskites-coated rooftops. Eu-enriched CsPbI3 layers are chosen to provide semi-transparency and phase stability while radicchio has limited size and grows in pots. Despite the reduced light exposure, radicchio seedlings exhibit faster growth and larger leaves than in the reference, benefiting from specific spectral filtering. RNA-sequencing reveals differential gene expression patterns reflecting adaptive responses to environmental changes. Simulations of full PSC integration demonstrate a positive energy balance in greenhouses to cover annual energy needs for lighting, irrigation, and air conditioning.
Photovoltaic bioelectronics merging biology with new generation semiconductors and light in biophotovoltaics photobiomodulation and biosensing
This review covers advancements in biosensing, biophotovoltaics, and photobiomodulation, focusing on the synergistic use of light, biomaterials, cells or tissues, interfaced with photosensitive dye-sensitized, perovskite, and conjugated polymer organic semiconductors or nanoparticles. Integration of semiconductor and biological systems, using non-invasive light-probes or -stimuli for both sensing and controlling biological behavior, has led to groundbreaking applications like artificial retinas. From fusion of photovoltaics and biology, a new research field emerges: photovoltaic bioelectronics.
Efficient and stable near-infrared InAs quantum dot light-emitting diodes
Visible quantum dot light-emitting diodes have satisfied commercial display requirements. However, near-infrared counterparts considerably lag behind due to the inferior quality of near-infrared quantum dots and limitations in device architecture suitable for near-infrared electroluminescence. Here, we present an efficient strategy using zinc fluoride to balance ZnSe shell growth across different core quantum dot facets, producing highly regular InAs/InP/ZnSe/ZnS quantum dots with near-unity quantum yield. Moreover, we develop a method of in-situ photo-crosslinking blended hole-transport materials for accurate energy level modulation. The crosslinked hole-transport layers enhance hole transfer to the emitting layer for balanced carrier dynamics in quantum dot light-emitting diodes. The resulting near-infrared quantum dot light-emitting diodes exhibit a peak external quantum efficiency of 20.5%, a maximum radiance of 581.4 W sr−1 m−2 and an operational half-lifetime of 550 h at 50 W sr−1 m−2. This study represents a step towards practical application of near-infrared quantum dot light-emitting diodes.
Surfactant-induced hole concentration enhancement for highly efficient perovskite light-emitting diodes
It is widely acknowledged that constructing small injection barriers for balanced electron and hole injections is essential for light-emitting diodes (LEDs). However, in highly efficient LEDs based on metal halide perovskites, a seemingly large hole injection barrier is usually observed. Here we rationalize this high efficiency through a surfactant-induced effect where the hole concentration at the perovskite surface is enhanced to enable sufficient bimolecular recombination pathways with injected electrons. This effect originates from the additive engineering and is verified by a series of optical and electrical measurements. In addition, surfactant additives that induce an increased hole concentration also significantly improve the luminescence yield, an important parameter for the efficient operation of perovskite LEDs. Our results not only provide rational design rules to fabricate high-efficiency perovskite LEDs but also present new insights to benefit the design of other perovskite optoelectronic devices.
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