SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3727-0
Lead halide perovskites are promising scintillators for X-ray imaging due to high X-ray absorption efficiency, excellent luminescence, and facile synthesis. However, their ionic nature challenges simultaneous high photoluminescence efficiency and environmental robustness. This work introduces a multilevel encapsulation strategy: CsPbBr3 quantum dots (QDs) are sequentially coated with Cs4PbBr6, SiO2, and polydimethylsiloxane (PDMS). Cs4PbBr6 passivates surface defects, while SiO2 and PDMS provide barriers against moisture, heat, and radiation. The resulting CsPbBr3@Cs4PbBr6/SiO2/PDMS flexible films exhibit a photoluminescence quantum yield (PLQY) of 85%, outstanding mechanical flexibility, and durability under stretching, bending, and compressing. Films retain emission stability under elevated temperatures, prolonged X-ray irradiation, and extended water immersion. X-ray imaging demonstrates spatial resolution of 12 lp/mm, enabling distortion-free imaging of curved objects; superior water resistance allows long-term underwater imaging. This work highlights hierarchical encapsulation in balancing luminescence efficiency and stability, offering a pathway toward practical flexible perovskite scintillators.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3692-9
Doping is essential for modulating semiconductor conductivity, forming p–n junctions, and reducing contact resistance. However, organic semiconductors (OSCs) face challenges in achieving precise regional doping due to uncontrollable dopant diffusion and poor process compatibility. This highlight discusses a breakthrough light-triggered strategy for spatially controlled n-type doping in OSCs, developed by Pei's Group. The method employs inert photoactivable dopants (iPADs) that are thermally stable but undergo rapid 6π-electrocyclization upon UV irradiation, transforming into potent n-dopants (PADs). These PADs irreversibly dope n-type OSCs via hydride transfer. With a high activation barrier (>28 kcal mol−1), the reaction is thermally suppressed even at 120°C, enabling orthogonal control: doping occurs only where and when light is applied. This approach achieves down to 1 μm spatial resolution, far surpassing physical masking methods. The method's universality accommodates diverse n-type OSCs (LUMO: −3.7 to −4.7 eV) with conductivity enhancements up to nine orders of magnitude (exceeding 30 S cm−1 in some systems). Doping levels, conductivity, and Fermi energy are tunable via UV dose and dopant concentration. The doped regions exhibit robust stability and withstand subsequent thermal processing, aligning with large-scale and flexible manufacturing. In organic field-effect transistors, precise spatial doping significantly enhances carrier mobility, reduces contact resistance to one-sixth of its original value, and effectively lowers surface trap density, providing critical support for device miniaturization and high-density integration.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4072-3
All-inorganic, hole-transport-material-free (HTM-free), carbon-based perovskite solar cells (C-PSCs) have attracted significant attention due to their exceptional stability and low cost. However, their performance and commercial potential are constrained by poor interfacial contact, insufficient crystallinity, and energy level misalignment. In this work, we address these challenges via a molecular engineering strategy by introducing tetrakis(4-ethynylphenyl)methane (TEPM) as a multifunctional additive. The alkynyl moiety (C≡C) in TEPM coordinates with Pb2+ ions in perovskite precursors, synergistically slowing crystallization kinetics to regulate crystal growth and passivate deep-level defects. Consequently, CsPbI3 films exhibit larger grain sizes, improved crystallinity, and lower defect densities. Devices modified with TEPM achieved a record power conversion efficiency (PCE) of 20.01% (certified 19.58%). Additionally, unencapsulated devices retained 87.6% of their initial efficiency after 1080 h under ambient conditions (25 °C, 30% relative humidity), and maintained 94.0% of their initial efficiency after 730 h of continuous AM 1.5G illumination in air. This work sets a new efficiency benchmark for inorganic HTM-free C-PSCs and provides a versatile molecular engineering strategy for developing high-performance, stable perovskite photovoltaics.