Novel C3N4-Assisted Bilateral Interface Engineering for Efficient and Stable Perovskite Solar Cells.

g-C3N4-assisted interface engineering has been developed as an effective method to improve the efficiency and stability of perovskite solar cells (PSCs). However, most of the reported works used g-C3N4-induced single-interface modification, which is difficult to passivate the bilateral interfaces of the perovskite layer at the same time. In this paper, we fabricated two kinds of C3N4 materials simultaneously (w-CN and y-CN) after the twice calcination of melamine and used them in the bilateral interface modification toward all-inorganic PSCs. The two kinds of C3N4 play different roles in different interface engineering. On the front interface, w-CN could optimize band level arrangement and improve the perovskite film quality, which contributes to the efficiency of the device. On the back interface, y-CN could also improve the film quality of the perovskite layer, accelerating the extraction of charge carriers. The champion efficiency of the CsPbIBr2-based device treated by the bilateral interface is significantly enhanced from 7.8 to 10.1%. Moreover, the modified perovskite film exhibits negligible degradation after 40 min of exposure in the ambient environment with a relative humidity of 70%, while the pristine perovskite film has a rapid degradation within 20 min.

Ultrasensitive Electrochemiluminescence Immunoassay Based on Signal Amplification of 0D Au-2D WS2 Nano-Hybrid Materials.

In this study, we proposed a novel Ru(bpy)32+-Au-WS2 nanocomposite (Ru-Au-WS2 NCs) nano-hybrid electrochemiluminescence (ECL) probe for the highly sensitive detection of carcinoembryonic antigen (CEA). This system utilizes Au nanoparticles (Au NPs) as a bridge to graft the high-performance of a Ru(bpy)32+ ECL emitter and WS2 nanosheet with excellent electrochemical performance into an ECL platform, which shows outstanding anodic ECL performance and biosensing platform due to the synergetic effect and biocompatibility of Au NPs and WS2 nanosheet. Because the ECL intensity of Ru(bpy)32+ is sensitively affected by the antibody-antigen insulator, a preferable linear dependence was obtained in the concentration range of CEA from 1 pg·mL-1 to 350 ng·mL-1 with high selectivity (LOD of 0.3 pg·mL-1, S/N = 3). Moreover, the ECL platform had good reproducibility and stability and exhibited excellent anti-interference performance in the detection process of CEA. We believe that the platform we have developed can expand the opportunities for the detection of additional high specificity-related antibodies/antigens and demonstrate broad prospects for disease diagnosis and biochemical research.

High-Efficiency Silicon Inverted Pyramid-Based Passivated Emitter and Rear Cells.

Surface texturing is one of the most important techniques for improving the performance of photovoltaic (PV) device. As an appealing front texture, inverted pyramid (IP) has attracted lots of research interests due to its superior antireflection effect and structural characteristics. In this paper, we prepare high-uniform silicon (Si) IPs structures on a commercial monocrystalline silicon wafer with a standard size of 156 × 156 mm2 employing the metal-assisted chemical etching (MACE) and alkali anisotropic etching technique. Combining the front IPs textures with the rear surface passivation of Al2O3/SiNx, we fabricate a novel Si IP-based passivated emitter and rear cell (PERC). Benefiting from the optical superiority of the optimized IPs and the improvement of electrical performance of the device, we achieve a high efficiency of 21.4% of the Si IP-based PERC, which is comparable with the average efficiency of the commercial PERC solar cells. The optimizing morphology of IP textures is the key to the improvement of the short circuit current Isc from 9.51 A to 9.63 A; meanwhile, simultaneous stack SiO2/SiNx passivation for the Si IP-based n+ emitter and stack Al2O3/SiNx passivation for rear surface guarantees a high open-circuit voltage Voc of 0.677 V. The achievement of this high-performance PV device demonstrates a competitive texturing technique and a promising prospect for the mass production of the Si IP-based PERC.

Copper-Ion-Assisted Precipitation Etching Method for the Luminescent Enhanced Assembling of Sulfur Quantum Dots.

In this study, we report a metal-ion-assisted precipitation etching strategy that can be used to manipulate the optical properties associated with the assembling of sulfur quantum dots (S dots) using copper ions. Transmission electron microscopy confirmed that the S dots were mainly distributed within 50-80 nm and that they exhibited an ambiguous boundary. After the post-synthetic Cu2+-assisted modification was completed, the assisted precipitation-etching S dots (APE-S dots) were observed to exhibit a relatively clear boundary with a high fluorescence (FL) quantum yield (QY) of 32.8%. Simultaneously, the Fourier transform infrared radiation, X-ray photoelectron spectra, and time-resolved FL decay spectra were used to illustrate the improvement in the FL QY of the APE-S dots.

The influence of silver core position on enhanced photon absorption of single nanowire α-Si solar cells.

Photon absorption of single nanowire solar cells can be modulated by metallic core. Silver core was integrated into α-Si single nanowire solar cells (SNSCs), and the influence of silver core position on enhanced photon absorption efficiency and the short circuit current (J(sc)) was investigated. The finite-difference time domain (FDTD) method was used to rigorously solve Maxwell's equations in two dimensions. The J(sc) decreases when the silver core is integrated into the center of nanowire. However, the photon absorption efficiencies and J(sc) could be enhanced by tuning the core position in the nanowire. J(sc) enhancement of 21.4% is achieved when nanowire radius R is 190 nm, core radius r is 30 nm, the silver core is located in the negative Y-axis and the distance from the center of silver core to the origin d is 102 nm under realistic solar illumination.

Full-band absorption enhancement in ultrathin-film solar cells through the excitation of multiresonant guided modes.

We demonstrate the optimization of plasmonic thin-film solar cells with broadband absorption enhancements. The solar cells model system consists of a three-dimensional, periodic array of Ag/silica cylinders on a Si film supported by a silica substrate. Particle swarm optimization (PSO) and the finite-difference time domain (FDTD) are combined to achieve the maximum absorption enhancement (Ehm). Through optimization, the optimal system parameters, such as the height and diameter of Ag and the silica cylinder, and the period of periodic array, were obtained. Following this approach, we can attain a 321% enhancement in the integrated quantum efficiency as compared to a cell without metallic structures. The full-band absorption enhancement arises from the near-field enhancement and multiresonant guided modes in the Si waveguide.