Perovskite solar cells (PSCs) are a promising and fast-growing type of photovoltaic cell due to their low cost and high conversion efficiency. The high efficiency of PSCs is closely related to the quality of the photosensitive layer, and the high-quality light absorbing layer depends on the growth condition of the crystals. In the formation of high-quality crystals, annealing is an indispensable and crucial part, which serves to evaporate the solvent and drive the crystallization of the film. Various annealing methods have different effects on the promotion of the film growth process owing to the way they work. Here, this review will present a discussion of the growth puzzles and quality of perovskite crystals under different driving forces, and then explain the relationship between the annealing driving force and crystal growth. We divided the main current annealing methods into physical and chemical annealing, which has never been summarized before. The main annealing methods currently reported for crystal growth are summarized to visualize the impact of annealing design strategies on photovoltaic performance, while the growth mechanisms of thin films under multiple annealing methods are also discussed. Finally, we suggest future perspectives and trends in the industrial fabrication of PSCs in the future. The review promises industrial manufacturing of annealed PSCs. The review is expected to facilitate the industrial fabrication of PSCs.

We investigated the effects of absorbent and weak turbulent seawater channels on the orbital angular momentum (OAM) mode carried by perfect optical vortex (POV) based on the Rytov approximation. After deriving the received probability of OAM modes, some numerical results are worked out to show that the receiving probability of OAM modes decreases linearly with the increase of virtual refractive index of the water body. An underwater communication link with POV as the signal carrier can obtain high receiving probability by adopting long signal wavelength in intervals of “seawater window wavelength,” low OAM quantum number, a POV with a larger ring radius, and a transmitter as well as receiver with a smaller aperture. The transmission distance of OAM mode carried by POV in four kinds of seawater is better than that of a Bessel–Gaussian beam.

The wander and long-term spread of a beam caused by turbulence are two important factors affecting channel targeting and information receiving in optics communication systems. In this paper, the wander and long-term spread of a perfect Laguerre–Gauss (PLG)/circular perfect Laguerre–Gauss (CPLG) beam in turbulent absorbing seawater are studied. The analytical expression of the wander for a CPLG beam in the weak turbulent fluctuation region and the analytical expression of the long-term spread for a CPLG beam in a weak to strong turbulent fluctuation region are derived by using the Rytov approximation and the generalized Huygens–Fresnel integral, respectively. Through numerical analysis, we find that the optimal beam diameter and self-convergence effect of the PLG beam exist under given communication link conditions, the long-term spread of PLG beam is smaller than that of the LG beam, but the wander evolution trend of the PLG beam with increasing propagation distance is opposite to that of the LG beam. PLG and CPLG beams have stronger resistance disturbance of turbulence than that of Laguerre–Gauss and circular Laguerre–Gauss beams, respectively.

To overcome the atmospheric turbulence aberration, and improve the quality of light beam in visible light communication (VLC), a compact 69-element deformable mirror (DM) using micro voice coil actuators was designed based on systematic theoretical analysis. The structural parameters of the micro voice coil actuator were optimized by electromagnetic theory and the finite element method. The DM was optimized from the aspects of thermal deformation, response time, coupling coefficient, and other parameters. Finally, wavefront fitting and residual calculation were completed according to the influence function. The optimized voice coil deformable mirror (VCDM) has a large phase stroke, good thermal stability, a short response time of less than 0.7 ms, and a large first resonance of 2045 Hz. The fitting residuals of the VCDM for the first 10 Zernike modes with a PV value of 8 μm are all below 10 nm (RMS). Compared with a similar DM, the obtained results from our compact VCDM indicate that it has a higher wavefront fitting precision. VCDM corrected complex random aberrations in the VLC scenario and improved the coupling efficiency of the signal beam, proving that the compact VCDM with high performance and low cost has a good application prospect in VLC systems.

Fano resonance is based on a plasmonic metasurface and has many applications in various fields. In this paper, we propose an independently adjustable graphene-based double-layer grating structure. We control multiple Fano resonances at different wavelengths and bandwidths by regulating the Fermi level thanks to the preeminent characteristic of graphene. Here, the equivalent resonator coupled-mode method is used to better describe the Fano resonance of this designed structure adequately, and the transmission spectra fit well. The functional switch could be achieved at different wavelengths by using Fano resonance. We can obtain excellent group refractive index of this designed structure, which means it has superior applications in slow light. The effect of the refractive index of the dielectric layer on the sensing performance is researched so that the structure has a good application in sensors. Furthermore, we look forward to making potential contributions to fabricate integrated optical sensors and devices based on those elaborately designed structures.