Explore the vast range of titles available.

Organic photodetectors (OPDs) have attracted continuous attention due to their outstanding advantages, such as tunability of detecting wavelength, low‐cost manufacturing, compatibility with lightweight and flexible devices, as well as ease of processing. Enormous efforts on performance improvement and application of OPDs have been devoted in the past decades. In this Review, recent advances in device architectures and operation mechanisms of phototransistor, photoconductor, and photodiode based OPDs are reviewed with a focus on the strategies aiming at performance improvement. The application of OPDs in spectrally selective detection, wearable devices, and integrated optoelectronics are also discussed. Furthermore, some future prospects on the research challenges and new opportunities of OPDs are covered. Recent progress in organic photodetectors is reviewed, including different device structures, features, and operation mechanisms. Benefiting from the improved performance, the applications of organic photodetectors for selective detection, wearability, and integrated devices are highlighted.

Interfacial trap-assisted nonradiative recombination hampers the development of metal halide perovskite solar cells (PSCs). Herein, we report a rationally designed universal passivator to realize highly efficient and stable single junction and tandem PSCs. Multiple defects are simultaneously passivated by the synergistic effect of anion and cation. Moreover, the defect healing effect is precisely modulated by carefully controlling the number of hydrogen atoms on cations and steric hindrance. Due to minimized interfacial energy loss, L-valine benzyl ester p-toluenesulfonate (VBETS) modified inverted PSCs deliver a power conversion efficiency (PCE) of 26.28% using vacuum flash processing technology. Moreover, by suppressing carrier recombination, the large-area modules with an aperture area of 32.144 cm 2 and perovskite/Si tandem solar cells coupled with VBETS passivation deliver a PCE of 21.00% and 30.98%, respectively. This work highlights the critical role of the number of hydrogen atoms and steric hindrance in designing molecular modulators to advance the PCE and stability of PSCs. The perovskite/electron transport layer interface in inverted solar cells suffers from severe nonradiative recombination losses. Here, authors employ amino acid salts to passivate the film surface, achieving a power conversion efficiency of 26.28% using vacuum flash processing technology.

The NiO x /perovskite interface in p-i-n inverted perovskite solar cells (PSCs) suffers from trap-assisted nonradiative recombination, chemical reactions and weak adhesion. The self-assembled molecules are usually designed to address the above issues. However, absonant bilateral bond strength with NiO x and perovskite hinders the realization of efficient and stable PSCs. Herein, a bilateral bond strength equilibrium strategy is proposed to stabilize the buried interface in inverted PSCs through functional group and spatial conformation engineering. 1-(benzothiaxole-2-ylthio)succnic acid (BTSA) is adsorbed on the surface of NiO x through the S atom, π-ring, and N atom in the benzothiazole, making benzothiazole ring parallel to the NiO x surface, which is beneficial for passivating bilateral defects and improving hole transport. This strategy leads to effective interfacial defect passivation, interfacial chemical reaction suppression and ameliorated electrical properties of NiO x films, enabling 1.53 eV PSCs and large-area module (764 cm 2 ) with a PCE of 26.98% (certified 26.65%) and 21.98%, respectively. The mismatched bilateral bond strength between NiO x and perovskite hinders the development of inverted perovskite solar cells. Here, authors adsorb 1-(benzothiaxole-2-ylthio)succinic acid on NiO x surface for passivating bilateral defects and achieve maximum efficiency close to 27% in stable devices.

Blue perovskite light-emitting diodes (PeLEDs) still remain poorly developed due to the big challenge of achieving high-quality mixed-halide perovskites with wide optical bandgaps. Halide exchange is an effective scheme to tune the emission color of PeLEDs, while making perovskites susceptible to high defect density due to solvent erosion. Herein, we propose a versatile strategy for nondestructive in-situ halide exchange to obtain high-quality blue perovskites with low trap density and tunable bandgaps through long alkyl chain chloride incorporated chloroform post-treatment. In comparison with conventional halide exchange method, the ionic exchange mechanism of the present strategy is similar to a bimolecular nucleophilic substitution process, which simultaneously modulates perovskite bandgaps and inhibits new halogen vacancy generation. Consequently, efficient PeLEDs across blue spectral regions are obtained, exhibiting external quantum efficiencies of 23.6% (sky-blue emission at 488 nm), 20.9% (pure-blue emission at 478 nm), and 15.0% (deep-blue emission at 468 nm), respectively. Zhang et al. report non-destructive halide exchange by employing butylammonium halide incorporated post-treatment to achieve perovskite with low trap density and tuneable bandgap for blue LEDs, with external quantum efficiencies of 23.6%, 20.9%, and 15.5% for emission peaks at 488, 478, and 468 nm, respectively.

Photonic crystals (PhCs) are a kind of artificial structures that can mold the flow of light at will. Polaritonic crystals (PoCs) made from polaritonic media offer a promising route to controlling nano-light at the subwavelength scale. Conventional bulk PhCs and recent van der Waals PoCs mainly show highly symmetric excitation of Bloch modes that closely rely on lattice orders. Here, we experimentally demonstrate a type of hyperbolic PoCs with configurable and low-symmetry deep-subwavelength Bloch modes that are robust against lattice rearrangement in certain directions. This is achieved by periodically perforating a natural crystal α-MoO 3 that hosts in-plane hyperbolic phonon polaritons. The mode excitation and symmetry are controlled by the momentum matching between reciprocal lattice vectors and hyperbolic dispersions. We show that the Bloch modes and Bragg resonances of hyperbolic PoCs can be tuned through lattice scales and orientations while exhibiting robust properties immune to lattice rearrangement in the hyperbolic forbidden directions. Our findings provide insights into the physics of hyperbolic PoCs and expand the categories of PhCs, with potential applications in waveguiding, energy transfer, biosensing and quantum nano-optics. Photonic crystals (PhCs) are artificial periodic materials that can be used to manipulate the flow of light. Here, the authors report the realization of asymmetric PhCs based on in-plane hyperbolic phonon polaritons in perforated α-MoO 3 , showing low-symmetry deep-subwavelength Bloch modes that are robust against lattice rearrangement in specific directions.

The development of ultra-high-definition organic light-emitting diodes (OLEDs) displays requires efficient and narrowband blue emission. Nevertheless, binary host-guest doped narrowband blue OLEDs still face significant challenges in simultaneously realizing high efficiency and negligible roll-off. Herein, a molecular construction strategy through the synergistic interplay between π-conjugation extension and functional complementarity fusion is proposed by incorporating a rigid boron-oxygen (BO) framework with carbazole building blocks. The constructed compounds exhibit increased triplet exciton recycling capability, high excited-state energy levels, and improved charge transporting features, showcasing significant potential as host matrices for blue devices. The sensitizer-free OLEDs achieve the narrowband blue emission with a CIEy value lower than 0.15, a maximum external quantum efficiency of 41.2%, and the suppressed efficiency roll-off at high luminance due to efficient energy transfer to blue guest emitters and elevated horizontal dipole orientation. This work strategically demonstrates a balance between high efficiency and reduced efficiency roll-off in binary narrowband blue OLEDs, representing a substantial advancement in blue electroluminescent technology. The realization of high efficiency and negligible roll-off simultaneously for blue organic light-emitting diodes remains challenging. Here, the authors incorporate carbazole building blocks into rigid boron oxygen framework and achieve a maximum efficiency of 41.2% for sensitizer-free devices.

The plasmonic effects have unlocked remarkable advancements in modern optoelectronics, enabling enhanced light-matter interactions for applications ranging from sensing to photovoltaics. However, the nonradiative damping of plasmonic effects causes parasitic absorption which limits the light-utilization efficiency of optoelectronics, particularly for photovoltaic cells. Herein, we propose a plasmon energy recycling scheme consisting of green fluorophore (BCzBN) and nickel oxide to compensate for the plasmon energy loss. The plasmons trapped in silver nanowire (AgNW) electrodes are coupled to green emission through plasmon-exciton energy exchange. Backward electron and energy transfer are inhibited due to the spectral mismatch and energy level offset. The optically enhanced flexible AgNW electrode exhibits an improvement of 10.74% in transmittance, yielding flexible organic solar cells with an efficiency of 19.51% and a certified value of 18.69%. This innovative strategy provides a pathway for overcoming plasmon energy losses in plasmonic optoelectronics, opening horizons for highly efficient flexible photovoltaics and plasmonic devices. The parasitic absorption caused by nonradiative damping of plasmonic effects limits the light utilization efficiency of optoelectronics. Here, authors employ green fluorophore and nickel oxide to recycle plasmon energy, achieving maximum device efficiency of 19.51% for flexible organic solar cells.

A small-molecule acceptor, S-Cb, substituted with a cyclobutyl group that introduces high ring strain, was designed and synthesized. Thanks to the rigid and planar structure of cyclobutyl, S-Cb can form interchain supramolecular interactions through hydrogen bonding with L8-BO at the external side chains. This clamping effect not only effectively suppresses the electron-phonon coupling but also promotes the formation of high-quality acceptor alloy phases in the ternary active layer, thereby optimizing carrier behaviors and reducing non-radiative energy loss. The clamping effect reaches its maximum when S-Cb and L8-BO are in equal proportion, where organic solar cells (OSCs) based on D18:S-Cb:L8-BO achieved an impressive efficiency of 20.93%, with a certified efficiency of 20.74%. In summary, the cyclobutyl-mediated interchain supramolecular interactions suppress the electron-phonon coupling and optimize the acceptor alloy phase for efficient ternary OSCs. Organic solar cells (OSCs) rely on morphological optimization for high efficiency. The authors show cyclobutyl-mediated interchain supramolecular interactions among acceptors, suppressing electron-phonon coupling and optimizing acceptor alloy phase morphology in ternary OSCs to achieve efficiencies approaching 21%.

Thermally activated delayed fluorescence (TADF) provides great potential for the realization of efficient and stable organic light‐emitting diodes (OLEDs). However, it is still challenging for blue TADF emitters to simultaneously achieve high efficiency, high brightness, and low Commission Internationale de l'Eclairage (CIE) y coordinate (CIEy) value. Here, the design and synthesis of two new benzonitrile‐based TADF emitters (namely 2,6‐di(9H‐carbazol‐9‐yl)‐3,5‐bis(3,6‐diphenyl‐9H‐carbazol‐9‐yl)benzonitrile (2PhCz2CzBn) and 2,6‐di(9H‐carbazol‐9‐yl)‐3,5‐bis(3,6‐di‐tert‐butyl‐9H‐carbazol‐9‐yl)benzonitrile (2tCz2CzBn)) with a symmetrical and rigid heterodonor configuration are reported. The TADF OLEDs doped with both the emitters can achieve a high external quantum efficiency (EQE) over 20% and narrowband blue emission of 464 nm with a CIEy < 0.2. Moreover, the incorporation of a terminal tert‐butyl group can weaken the intermolecular π–π stacking in the nondoped TADF emitter, and thus significantly suppress self‐aggregation‐caused emission quenching for enhanced delayed fluorescence. A peak EQE of 21.6% is realized in the 2tCz2CzBn‐based nondoped device with an extremely low turn‐on voltage of 2.7 V, high color stability, a high brightness over 20 000 cd m−2, a narrow full‐width at half‐maximum of 70 nm, and CIE color coordinates of (0.167, 0.248). A new blue thermally activated delayed fluorescence emitter of 2tCz2CzBn is synthesized with a symmetrical and rigid heterodonor configuration, enabling significant suppression of self‐aggregation‐caused emission quenching. High‐performance nondoped organic light‐emitting diodes are achieved with a high external quantum efficiency of 21.6%, an extremely low turn‐on voltage of 2.7 V, and narrowband blue emission.

Inorganic mixed‐halide CsPbX3‐based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic–inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol–gel‐derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs2CO3. Compared to bare ZnO, Cs2CO3‐doped ZnO possesses more favorable interface energetics in contact with the CsPbI2Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open‐circuit voltage of 1.28 V, together with an increase in fill factor and short‐circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs2CO3‐doped ZnO/CsPbI2Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C. An all‐inorganic mixed‐halide perovskite solar cell with a power conversion efficiency of 16.42% is realized by using a Cs2CO3‐doped ZnO electron transport layer, which ascribes to the interfacial energy level tuning for reducing ohmic loss at the contact and enlarging the built‐in potential. A high thermostability is simultaneously obtained via surface defect passivation for improving the CsPbI2Br film against phase transformation.