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This work presents the advancement of lead‐free tin perovskite photodiodes in terms of their photodetection and air stability by incorporating germanium (Ge) and ethylenediamine (EDA) to formamidinium tin iodide (FASnI3). EDA0.01FA0.98SnI3:Ge‐based photodiodes demonstrate a significantly improved specific detectivity (1.6 × 1012 Jones at −0.1 V), cut‐off frequency (6.6 × 105 Hz), response speed (0.53 µs), and signal‐to‐noise ratio (45 dB) compared with control devices. The superior performance is attributed to the stronger Ge─I bond, the passivation of Sn2+ and I– vacancies by smaller Ge2+ ions, the promotion of a fully 3D perovskite structure, the elevation of the conduction band energy level, and the formation of a protective GeO layer. Various film analyses, including X‐ray photoelectron spectroscopy, UV photoelectron spectroscopy, density functional theory, as well as device testing using time‐of‐flight secondary ion mass spectrometry and voltage‐dependent admittance, support and explain the mechanisms behind the enhancements. Ge‐ and EDA‐incorporated photodiodes exhibit excellent air stability, as evidenced by the time‐dependent ultraviolet visible spectra and the considerably high certified power conversion efficiency without encapsulation in air, demonstrating their potential for practical applications. The obtained photodetection performance is highest among the published lead‐free tin‐based perovskite photodetectors, presenting a monumental progress from the previous report of the same group. [ABSTRACT FROM AUTHOR]

This study attempts to develop a reproducible thin‐film formation technique called vacuum‐free (VF) lamination, which transfers thin films using elastomeric polymer‐based laminating mediators. Precisely, by controlling the interface characteristics of the mediator based on the work of adhesion, VF lamination is successfully performed for various thicknesses (from 20 to 240 nm) of a conjugated photoactive material composed of poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐bʹ]dithiophene))‐alt‐(5,5‐(1ʹ,3ʹ‐di‐2‐thienyl‐5ʹ,7ʹ‐bis(2‐ethylhexyl)benzo[1ʹ,2ʹ‐c:4ʹ,5ʹ‐cʹ]dithiophene‐4,8‐dione)] (a polymer donor) and 2,2ʹ‐((2Z,2ʹZ)‐((12,13‐bis(2‐butyloctyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2ʹʹ,3ʹʹ:4ʹ,5ʹ]thieno[2ʹ,3ʹ:4,5]pyrrolo[3,2‐g]thieno[2ʹ,3ʹ:4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile (a nonfullerene acceptor). Interestingly, the organic photovoltaic and photodetecting applications, prepared by the VF lamination process, showed superior performance compared to those of devices prepared by conventional spin‐coating. This is due to the overturned surface morphology, which led to enhanced charge transport ability and blocking of the externally injected charge. Thus, the reproducible VF lamination process, exploiting an adhesion‐based elastomeric polymer mediator, is a promising thin‐film formation technique for developing efficient next‐generation organic optoelectronic materials consistent with the solution process. [ABSTRACT FROM AUTHOR]

Photodetectors made from low‐toxicity organic materials are considered a promising alternative to conventional inorganic photodetectors. However, the performance of current organic photodetectors (OPD) needs to be further enhanced. This study aims to introduce acid‐free poly(3,4‐ethylenedioxythiophene)‐(polystyrene sulfonate) (PEDOT‐(PSS)) films in order to improve the performance of OPDs in practical applications. Utilization of heterocyclic 1,3‐diazole (HDZ) in PEDOT‐(PSS) improves the polymerization degree, carrier mobility, and other physicochemical properties. These enhanced properties also improve the comprehensive performance of OPD. In this flow, the enhanced noise suppression is also confirmed by elucidating the device's performance limitations. Consequently, the presented OPD‐based photoplethysmography sensor has the ability to diagnose blood circulation status and cardiovascular diseases. This accomplishment marks the first in single pixel‐based organic photodiode research. [ABSTRACT FROM AUTHOR]

Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical properties. Although nanoscale perovskite materials such as quantum dots (QDs) show novel behavior, they have intrinsic stability issues. In this study, an effectively silane barrier‐capped quantum dot (QD@APDEMS) is thinly applied onto a bulk perovskite photosensitive layer for use in photodetectors. QD@APDEMS is synthesized with a silane ligand with hydrophobic CH3‐terminal groups, resulting in excellent dispersibility and durability to enable effective coating. The introduction of the QD@APDEMS layer results in the formation of a low‐defect perovskite film with enlarged grains. This is attributed to the grain boundary interconnection effect via interaction between the functional groups of QD@APDEMS and uncoordinated Pb2+ in grain boundaries. By passivating the grain boundaries, where various trap sites are distributed, hole charge‐carrier injection and shunt leakage can be suppressed. Also, from the energy point of view, the deep highest occupied molecular orbital (HOMO) level of QD@APDEMS can work as a hole charge injection barrier. Improved charge dynamics (generation, transfer, and recombination properties) and reduced trap density of QD@APDEMS are demonstrated. When this perovskite film is used in a photodetector, the device performance (especially the detectivity) stands out among existing perovskites evaluated for energy sensing device applications. [ABSTRACT FROM AUTHOR]