Multi-scale optical simulation of crystalline silicon solar cells by combining ray and wave optics.

Optical simulations allow the evaluation of the absorption, reflection, and transmission of each functional layer of solar cells and, therefore, are of great importance for the design of high-efficiency crystalline silicon (c-Si) solar cells. Here, a multi-scale simulation method (MSM) based on ray and wave optics is proposed to investigate the optical characteristics of c-Si solar cells. The ray and wave optical methods are first independently employed on inverted pyramid glass sheets, where the latter one can describe the size-dependent interfacial scattering characteristics more accurately. Then the optical properties of a c-Si solar cell with a tunnel oxide passivated carrier-selective contact configuration are studied by employing the MSM, where scattering at the interfaces is acquired by a finite-difference time-domain method (wave optics). Since the MSM can accurately simulate optical modes such as the Rayleigh anomaly, Bloch mode, and Mie resonances, the reflection and transmission spectra of the whole device are in good agreement with the measured data. The proposed MSM has proven to be accurate for structures with functional thin films, which can be extended to hybrid tandem devices with top-level cells consisting of stacks of layers with similar dimensions.

Surfactant-activated lipase hybrid nanoflowers with enhanced enzymatic performance.

Increasing numbers of materials have been extensively used as platforms for enzyme immobilization to improve catalytic performance. However, activity of the most of the enzymes was declined after immobilization. Here, we develop a surfactant-activated lipase-inorganic flowerlike hybrid nanomaterials with rational design based on interfacial activation and self-assembly. The resulting surfactant-activated lipase-inorganic hybird nanoflower (activated hNF-lipase) exhibited 460% and 200% higher activity than native lipase and conventional lipase-inorganic hybird nanoflower (hNF-lipase). Furthermore, the activated hNF-lipase displayed good reusability due to its monodispersity and mechanical properties, and had excellent long-time stability. The superior catalytic performances were attributed to both the conformational modulation of surfactants and hierarchical structure of nanoflowers, which not only anchored lipases in an active form, but also decreased the enzyme-support negative interaction and mass-transfer limitations. This new biocatalytic system is promising to find widespread use in applications related to biomedicine, biosensor, and biodiesel.