Xiaoyu Wang

Controlling the perovskite morphology and defects at the buried perovskite-substrate interface is challenging for inverted perovskite solar cells. In this work, we report an amphiphilic molecular hole transporter, (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanovinyl)phosphonic acid, that features a multifunctional cyanovinyl phosphonic acid group and forms a superwetting underlayer for perovskite deposition, which enables high-quality perovskite films with minimized defects at the buried interface. The resulting perovskite film has a photoluminescence quantum yield of 17% and a Shockley-Read-Hall lifetime of nearly 7 microseconds and achieved a certified power conversion efficiency (PCE) of 25.4% with an open-circuit voltage of 1.21 volts and a fill factor of 84.7%. In addition, 1-square centimeter cells and 10-square centimeter minimodules show PCEs of 23.4 and 22.0%, respectively. Encapsulated modules exhibited high stability under both operational and damp heat test conditions.

In this paper, we propose a Timed Efficient and Secure Vehicular Communication (TSVC) scheme with privacy preservation, which aims at minimizing the packet overhead in terms of signature overhead and signature verification latency without compromising the security and privacy requirements. Compared with currently existing public key based packet authentication schemes for security and privacy, the communication and computation overhead of TSVC can be significantly reduced due to the short message authentication code (MAC) tag attached in each packet for the packet authentication, by which only a fast hash operation is required to verify each packet. Simulation results demonstrate that TSVC maintains acceptable packet latency with much less packet overhead, while significantly reducing the packet loss ratio compared with that of the existing public key infrastructure (PKI) based schemes, especially when the road traffic is heavy.

Monodispersed copolymer latex particles functionalized by surface carboxylate groups are used as effective colloidal templates for the controlled crystallization of calcium carbonate in solution. After template removal, well-defined, calcite single crystals exhibiting a rhombohedral morphology and uniform surface pores are obtained. The surface pore size of the calcite single crystals can be readily adjusted through introduction of latex particles with varied sizes. The effects of the surface functional groups of the latexes, the concentration of the latex dispersion and CaCl2 solution and the temperature during the CaCO3 crystallization have been investigated. A three-step mechanism has been proposed for the formation of the composite particles consisting of calcite single crystals and latex particles, and it has been demonstrated that this synthesis strategy is potentially extendable to the synthesis of regularly shaped composite particles consisting of single crystals of other inorganic materials, such as Cu2O. In addition, surface-patterned calcite crystals with hierarchical architectures are prepared at a relatively high concentration of latex particles, which act as both colloidal templates and crystal growth modifiers.