Physical and chemical properties and degradation of MAPbBr3 films on transparent substrates.

To date, the potential exploitation of hybrid organic-inorganic perovskites (HOIPs) in photovoltaic technologies has been significantly hampered by their poor environmental stability. HOIP degradation can be triggered by conventional operational environments, with excessive heating and exposure to oxygen and moisture significantly reducing the performances of HOIP-based solar cells. An imperative need emerges for a thorough investigation on the impact of these factors on the HOIP stability. In this work, the degradation of methylammonium lead bromide (CH3NH3PbBr3) thin films, deposited via spin-coating on indium tin oxide (ITO) and strontium titanate (STO) substrates, was investigated by combining Raman and ultraviolet-visible (UV-Vis) absorption spectroscopy, as well as optical and fluorescence microscopy. We assessed the physical and chemical degradation of the films occurring under diverse preservation conditions, shedding light on the byproducts emerging from different degradation pathways and on the optimal HOIP preservation conditions.

Direct detection of minimum ionizing charged particles in a perovskite single crystal detector with single particle sensitivity.

We report the detection of high energy electrons of some hundreds of MeV, crossing a methylammonium lead bromide single crystal device with sensitivity down to a single electron. In the device, the released energy is close to the energy released by minimum-ionizing particles. This is the first demonstration of a perovskite-based device that can be used for tracking and counting minimum-ionizing charged particles. The device reaches single particle sensitivity with a low bias voltage of 5 V. It also shows a good linearity of the response as a function of the number of electrons in a dynamic range of approximately 104.

Low-temperature strain-free encapsulation for perovskite solar cells and modules passing multifaceted accelerated ageing tests.

Perovskite solar cells promise to be part of the future portfolio of photovoltaic technologies, but their instability is slow down their commercialization. Major stability assessments have been recently achieved but reliable accelerated ageing tests on beyond small-area cells are still poor. Here, we report an industrial encapsulation process based on the lamination of highly viscoelastic semi-solid/highly viscous liquid adhesive atop the perovskite solar cells and modules. Our encapsulant reduces the thermomechanical stresses at the encapsulant/rear electrode interface. The addition of thermally conductive two-dimensional hexagonal boron nitride into the polymeric matrix improves the barrier and thermal management properties of the encapsulant. Without any edge sealant, encapsulated devices withstood multifaceted accelerated ageing tests, retaining >80% of their initial efficiency. Our encapsulation is applicable to the most established cell configurations (direct/inverted, mesoscopic/planar), even with temperature-sensitive materials, and extended to semi-transparent cells for building-integrated photovoltaics and Internet of Things systems.

Flexible, Transparent, and Bifacial Perovskite Solar Cells and Modules Using the Wide-Band Gap FAPbBr3 Perovskite Absorber.

Perovskite solar cells (PSCs) offer impressive performance and flexibility, thanks to their simple, low-temperature deposition methods. Their band gap tunability allows for a wide range of applications, transitioning from opaque to transparent devices. This study introduces the first flexible, bifacial PSCs using the FAPbBr3 perovskite. We investigated the impact of optimizing electron and hole transport layers on the cells' bifaciality, transparency, and stability. PSCs achieved a maximum power conversion efficiency (PCE) of 6.8 and 18.7% under 1 sun and indoor light conditions (1200 lx), respectively, showing up to 98% bifaciality factor and an average visible transmittance (AVT) of 55%. Additionally, a P1-P2-P3 laser ablation scheme has been developed on the flexible poly(ethylene terephthalate) (PET) substrate for perovskite solar modules showing a PCE of 4.8% and high geometrical fill factor (97.8%). These findings highlight the potential of flexible, bifacial PSCs for diverse applications such as building-integrated photovoltaics (BIPV), agrivoltaics, automotive technology, wearable sensors, and Internet of things (IoT).

Metal-Halide Perovskite Submicrometer-Thick Films for Ultra-Stable Self-Powered Direct X-Ray Detectors.

Metal-halide perovskites are revolutionizing the world of X-ray detectors, due to the development of sensitive, fast, and cost-effective devices. Self-powered operation, ensuring portability and low power consumption, has also been recently demonstrated in both bulk materials and thin films. However, the signal stability and repeatability under continuous X-ray exposure has only been tested up to a few hours, often reporting degradation of the detection performance. Here it is shown that self-powered direct X-ray detectors, fabricated starting from a FAPbBr3 submicrometer-thick film deposition onto a mesoporous TiO2 scaffold, can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss, demonstrating ultra-high operational stability and excellent repeatability. No structural modification is observed after irradiation with a total ionizing dose of almost 200 Gy, revealing an unexpectedly high radiation hardness for a metal-halide perovskite thin film. In addition, trap-assisted photoconductive gain enabled the device to achieve a record bulk sensitivity of 7.28 C Gy-1 cm-3 at 0 V, an unprecedented value in the field of thin-film-based photoconductors and photodiodes for "hard" X-rays. Finally, prototypal validation under the X-ray beam produced by a medical linear accelerator for cancer treatment is also introduced.