Sercan Ozen

Metal halide perovskites (MHPs) combine excellent optoelectronic properties with strong X-ray attenuation, offering a promising platform for high performance and adaptable radiation detectors beyond the limitations of conventional rigid semiconductors. However, state of the art performance has so far been restricted to rigid single crystal perovskite devices, while flexible film-based counterparts have significantly lagged. Here, we close this gap by embedding a polymer-perovskite composite into a mechanically robust yet flexible Teflon membrane. Through comprehensive spectroscopic analysis, we provided direct evidence for a dual-action interaction mechanism, where PMA passivates the inorganic Pb²⁺ lattice to enhance phase stability while also interacting with the organic FA⁺ cations to promote a more ordered local environment. This interaction enhances crystallinity and suppresses non-radiative recombination. As a result, our flexible detectors deliver an outstanding sensitivity of 2.3 × 10⁵ µC Gy_air ⁻¹ cm⁻² and an ultra-low detection limit of 0.09 nGy_air s⁻¹. Importantly, this high performance is accompanied by excellent device to device reproducibility, long term stability in ambient conditions, and robust mechanical durability under bending. This work presents a comprehensive strategy for developing flexible perovskite based X-ray detectors that simultaneously achieve record sensitivity and practical reliability, enabling the development of next-generation wearable and medical imaging applications.

All-perovskite triple-junction solar cells are monitored in operando under simultaneous AM0 illumination and 68 MeV proton irradiation, revealing R (PCE) > 0.99 in the dark and ∼0.87 under AM0 illumination, with preserved absorber level performance.

All‐perovskite tandem solar cells (2J‐PSCs) reach the highest power‐to‐weight ratios, making them promising candidates for space applications. To determine their potential for future deep space missions, this study assesses the performance of 2J‐PSCs under low‐intensity and low‐temperature (LILT) conditions, akin to those found near Saturn, the Asteroid belt, or in eclipse. Temperature‐dependent current density‐voltage ( J – V ) measurements under varying solar intensities (AM0, 0.1 AM0, 0.01 AM0) reveal that the 2J‐PSCs, comprising 1.80 eV high‐bandgap and 1.27 eV low‐bandgap perovskites, exhibit significant efficiency losses at lower temperatures and low light levels. In contrast, 1.54 eV single‐junction PSCs (1J‐PSCs) exhibit resilient performance, maintaining or even increasing their power conversion efficiency at low temperatures. The main performance problem of the 2J‐PSCs is then identified as a demixing of the 1.80 eV perovskite due to its high Br ratio at temperatures below 250 K. This demixing at low temperatures leads to a significant increase in ion‐induced performance losses as well as current imbalances between the two subcells in the monolithic tandem. Together, this causes severe S‐shapes in solar cell operation and impedes the operation of the monolithic interconnected tandem solar cells. Notably, these limitations vanish upon heating, leading to a recovery of performance.

In this work, we fabricate & test MA-free co-evaporated perovskite solar cells that could potentially be fabricated in space. Pseudo-JV characteristics & electroluminescence hereby help to distinguish radiation damage from parasitic effects.

Two-dimensional (2D) Janus materials are a new class of materials with unique physical, chemical, and quantum properties. The name “Janus” originates from the ancient Roman god which has two faces, one looking to the future while the other facing the past. Janus has been used to describe special types of materials which have two faces at the nanoscale. This unique atomic arrangement has been shown to present rather exotic properties with applications in biology, chemistry, energy conversion, and quantum sciences. This review article aims to offer a comprehensive review of the emergent quantum properties of Janus materials. The review starts by introducing 0D Janus nanoparticles and 1D Janus nanotubes, and highlights their difference from classical ones. The design principles, synthesis, and the properties of graphene-based and chalcogenide-based Janus layers are then discussed. A particular emphasis is given to colossal built-in potential in 2D Janus layers and resulting quantum phenomena such as Rashba splitting, skyrmionics, excitonics, and 2D magnetic ordering. More recent theoretical predictions are discussed in 2D Janus superlattices when Janus layers are stacked onto each other. Finally, we discuss the tunable quantum properties and newly predicted 2D Janus layers waiting to be experimentally realized. The review serves as a complete summary of the 2D Janus library and predicted quantum properties in 2D Janus layers and their superlattices.