Abstract Shortwave infrared (SWIR) imaging devices have gained increasing importance in various fields, including security monitoring, biomedical imaging, advanced driver assistance, and semiconductor industry. However, complex technological processes of epitaxial growth and flip‐chip bonding hinder the development of high‐performance and low‐cost SWIR imaging devices. Herein, a novel organic–inorganic hybrid optical up‐conversion (OUC) imaging device by stacking a phosphorescent organic light‐emitting diode (OLED) with a NiSix/Si Schottky barrier diode (SBD) is developed. The pyramidal microstructures of silicon are utilized to greatly enhance light absorption of the NiSix/Si SBD, enabling the device to respond to a broadband SWIR light of 1064, 1310, and 1550 nm that are beyond the bandgap limit of silicon. Significantly, the device demonstrates excellent up‐conversion imaging behaviors at SWIR light with an ultra‐fast refresh rate of over 3000 Hz and a high‐resolution imaging capability of 508 ppi. This work paves the way toward the fabrication of high‐performance, low‐cost silicon‐based OUC devices for SWIR imaging applications.
Growing interest in hybrid organic-inorganic lead halide perovskites has led to the development of various perovskite nanowires (NWs), which have potential use in a wide range of applications, including lasers, photodetectors, and light-emitting diodes (LEDs). However, existing nanofabrication approaches lack the ability to control the number, location, orientation, and properties of perovskite NWs. Their growth mechanism also remains elusive. Here, we demonstrate a micro/nanofluidic fabrication technique (MNFFT) enabling both precise control and in situ monitoring of the growth of perovskite NWs. The initial nucleation point and subsequent growth path of a methylammonium lead iodide-dimethylformamide (MAPbI3·DMF) NW array can be guided by a nanochannel. In situ UV-vis absorption spectra are measured in real time, permitting the study of the growth mechanism of the DMF-mediated crystallization of MAPbI3. As an example of an application of the MNFFT, we demonstrate a highly sensitive MAPbI3-NW-based photodetector on both solid and flexible substrates, showing the potential of the MNFFT for low-cost, large-scale, highly efficient, and flexible optoelectronic applications.
Organic solar cells (OSCs) without proper encapsulation undergo a continuous degradation when exposed to air. However an interim improvement in the performance of freshly made OSCs is often observed after they are subjected to a short exposure to air. The mechanism of such an interim performance improvement has not been fully understood yet. In this study, it is found that the band tail states in the photo active layer, formed due to the air exposure, correlated closely with the initial enhancement in the performance of OSCs. The results reveal that the longer lifetime and larger charge separation distance, caused by the presence of the band tail states, are beneficial for the charge separation and collection in OSCs. The free carriers generated from charge–exciton interaction also contribute to the increase in photocurrent.
Abstract When a C 60 -based device with the structure indium tin oxide (ITO)/ N , N ′-di-[(1-naphthyl)- N , N ′-diphenyl]-1,1′-biphenyl)-4,4′-diamine (NPB)/fullerene (C 60 )/tris-(8-hydroxyquinoline) aluminium (Alq 3 )/aluminium (Al) is treated as a p-type sensitized solar cell, some methods for improving charge transportation and suppressing charge backflow in dye-sensitized solar cells can be applied to increase the performance of the C 60 device. In this study, a 5 nm layer of molybdenum oxide (MoO 3 ) is inserted between ITO and NPB to realize this idea. This thin layer with higher mobility and higher dielectric constant than NPB forms a cascade energy alignment with NPB, improving hole injection from C 60 into NPB and hole transportation from NPB to ITO. The power conversion efficiency (PCE) of the C 60 -based device with MoO 3 is enhanced to 0.976%, which is 3.92 times that of the device without MoO 3 . When MoO 3 is replaced by copper phthalocyanine or rubrene, which has higher mobility than NPB and forms a cascade energy structure with NPB, the PCE of C 60 -based devices is improved to 0.539% and 0.529% respectively, which is 2.16 and 2.12 times that of devices without such treatments.
An organic solar cell is a kind of photovoltaic cell that uses organic electronics, a branch of electronics that presents small organic molecules of conductive organic polymers for charge transport and light absorption until a photovoltaic effect produces electricity from sunlight. Regarding this, a computer simulation is presented to analyze the resonance analysis and dynamic stability of the organic solar cell. For simulating the size effects, the nonlocal strain gradient theory that adds some terms to the displacement and time terms of governing equations is presented. As the first step, the Navier method is applied as the analytical solver of the governing differential equations developed on the foundations to find the dynamics of the design points. The accuracy of the first step is tested and validated by a comparison study with those recorded in the high-quality papers. The results show that viscoelastic foundation, size-dependent parameter, and geometrical parameters can have a marvelous influence on the stability and dynamic deflection of the organic solar cells. The most relevant result is that the effect of size-dependent parameters on the dynamics of the organic cell is more remarkable at the higher value of the thickness of the cell.
Owing to its high electrical conductivity, unique layered structure, and strong hydrophilicity, two-dimensional titanium carbide (Ti3C2Tx) has attracted considerable attention as an electrode material for energy storage systems (EESs). However, applications of Ti3C2Tx to EESs are severely limited by self-restacking and –F surface terminations, which are usually inevitable during Ti3C2Tx preparation. To improve the electrochemical performance of Ti3C2Tx, the present authors doped Ti3C2Tx with nitrogen, preparing N–Ti3C2Tx, via thermal decomposition of urea. The interlayer spacing increased from 1.17 nm in Ti3C2Tx to 1.33 nm in N–Ti3C2Tx and the –F surface termination was largely reduced. Benefiting from the synergistic effect of modified surface termination and expanded interlayer spacing, the prepared N–Ti3C2Tx electrode in 1 M H2SO4 delivers a high specific capacitance (390 F g−1) at a current density of 1 A g−1 (approximately twice that of pristine Ti3C2Tx). To demonstrate the effectiveness of the method in other EESs, the Zn2+-storage capacity of the N–Ti3C2Tx electrode was tested in 1 M ZnSO4. The electrode exhibited a capacitance of 252 F g−1 at 1 A g−1, exceeding that of the pristine Ti3C2Tx electrode (212 F g−1). Furthermore, a supercapacitor, and a N–Ti3C2Tx//MnO2–CNTs system are fabricated using N–Ti3C2Tx, and it delivers a higher energy density and power density than the system with Ti3C2Tx electrode. The proposed strategy can facilely functionalize Ti3C2Tx for use in different high-performing EESs.
Benefiting from the intrinsically different and complementary electronic functionalities, organic/inorganic semiconductor heterostructures offer many tantalizing opportunities to create high-performance, low-cost, multifunctional optoelectronic devices. Compared with their bulk counterparts, organic/inorganic core–shell heterojunction nanowires (NWs) possess superior performances in terms of fewer interface defects, sufficient interfacial interactions, and high carrier collection efficiency, as well as easy and flexible device integration. However, the precise spatial control and large-area synthesis of organic/inorganic core–shell heterostructures currently remain a complex and daunting task, mainly due to the large lattice mismatch and the energetically unfavorable nucleation interface between two distinct chemical constituents. Here, an organic NW-guided atomic layer heteroepitaxy strategy is developed to realize large-scale and spatially controlled synthesis of a new type of semiconductor heterostructures made of p-type single-crystalline copper phthalocyanine (CuPc) and n-type polycrystalline cadmium sulfide (CdS). By rationally engineering the surface chemistry of the organic NWs and controlling the nucleation condition of the CdS, p-CuPc/n-CdS heterostructures with on-demand structural morphologies and optical properties can be constructed. In addition, the delicately designed p-CuPc/n-CdS core–shell NWs exhibit good photovoltaic behavior and excellent photosensitivity with broadband spectrum detection from ultraviolet-visible to near-infrared. This work provides a promising route for developing novel functional p-CuPc/n-CdS core–shell heterojunctions, while demonstrating the great potential of this new type of hybrid system in high-performance broadband photodetection and photovoltaic device application.
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